cOS Core Getting Started Guide for KVM

This section describes using Virtual Machine Manager to manually create a virtual machine for cOS Core.

The creation of a virtual machine on an x86 platform can be automated using a script.

An example script is called prepare.sh is listed in the Clavister Knowledge Base at the following link:

https://kb.clavister.com/332440471

The prepare.sh script is written in bash and is not supported by Clavister. It is provided only as a reference script for cOS Core setup under KVM and it can be freely used, modified or redistributed under the GPL open source license. As far as Clavister is aware, the script is suitable for KVM running under most Linux distributions.

The process for creating a virtual machine using the example script can be summarized as follows:

Install bridge-utils or Open vSwitch

Either bridge-utils or Open vSwitch must be installed for networking functions. Both cannot be installed at the same time. If the virtual firewall is going to be part of an HA cluster then Open vSwitch must be installed. However, Open vSwitch can also be used for standalone virtual firewalls.

The prepare.sh script will ask which of the two is installed and configure the networking accordingly.

Detailed Steps for Virtual Machine Definition

Once the Linux system has been set up with the required software installed, the series of steps for creating virtual machine for cOS Core are as follows:

Changing the Virtual Machine Configuration

The initial configuration parameters of the virtual machine created will be those specified in the configuration XML file created by the script but these can be changed later as required. For example, the amount of RAM memory allocated may need to be increased. Making these changes on an existing virtual machine is described in Chapter 4, Configuring Virtual Machines.

The KVM Console

When cOS Core starts, KVM will display a console which represents the console that is normally directly connected to the local console port of a physical firewall. This console is accessed by using VNC to connect to the IP address and port previously specified when running the script prepare.sh.

This console displays output from cOS Core exactly as it would be displayed with a non-virtual firewall. It will show the initial startup sequence output and this can be interrupted, if required, by key presses in order to enter the boot menu. After startup, the KVM console can be used to issue CLI commands to configure cOS Core further and this is described in Section 6.4, Manual CLI Setup.

The Default Virtual Ethernet Interfaces

By default, the standard cOS Core installation provides three virtual Ethernet interfaces. To function, these virtual NICs must be mapped to the correct bridge or physical Ethernet interface by changing the Source device property for the interface using Virtual Machine Manager (virt-manager). Doing this is described in Chapter 4, Configuring Virtual Machines. The Device model property will remain as the default value of virtio

cOS Core assigns the following default logical names to the virtual interfaces:

Connecting to the Virtual Firewall

By default, cOS Core enables a DHCP client on all the Ethernet interfaces so they can receive an IP address from a suitably configured external DHCP server. If DHCP is not used, an IP address must be assigned to the management interface manually and doing this is described in Section 6.4, Manual CLI Setup. Once assigned, this IP address can be used for a network connection using the cOS Core CLI over SSH or using the cOS Core WebUI over HTTPS.

The management computer running the web browser or SSH client can be one of the following:

In both the above cases, the real or virtual management computer needs its connecting Ethernet interface configured with an IP address on the same network as the cOS Core interface. Once this is done, the management computer and the firewall can communicate and initial cOS Core setup can then be performed in exactly the same way as a non-virtual firewall. This is described next in Chapter 6, Configuring cOS Core.

Setup with Multiple Virtual Firewalls

When there are multiple virtual machines running cOS Core under one KVM host, the IP address of the management virtual Ethernet interface must be different for the different virtual machines if administration is to be done through the Web Interface or an SSL client.

The recommended way to change the management interface IP address is to enter CLI commands into the cOS Core console which is displayed by KVM after cOS Core starts. The commands to do this for the If1 interface are the following:

The Default Management Interface

After first-time startup, cOS Core scans the available Ethernet interfaces and makes management access available on the first interface which is If1. A DHCP client is automatically enabled on all interfaces by cOS Core so the If1 interface can be automatically assigned a management IPv4 address from a suitably configured external DHCP server.

If an IPv4 address is to be manually assigned to the If1 interface then the interface's DHCP client function must first be disabled and an IP address and network assigned to the interface address objects that are automatically created by cOS Core in the folder InterfaceAddresses. This is done using CLI commands entered via the local console interface after initial startup and is described further at the beginning of Section 6.4, Manual CLI Setup.

cOS Core Setup Methods

Assuming that an IP address has been assigned to the management interface, initial cOS Core software configuration can be done in one of the following ways:

Network Connection Setup

For setup using the Web Interface or using remote CLI, an external management computer must be first physically connected to cOS Core across a network. This connection is described previously in Chapter 3, Creating Virtual Machines.

The default logical cOS Core management interface with KVM is If1 and the corresponding physical Ethernet port associated with this should be connected to the same network as the management computer (or a network accessible from the computer via one or more routers). Typically the connection is made via a switch or hub in the network using a regular straight-through Ethernet cable, as illustrated below.

For connection to the public Internet, one of the other interfaces should be connected to an ISP and this interface is sometimes referred to here and in the setup wizard as the WAN interface.

This section describes the setup when accessing cOS Core for the first time through a web browser. The cOS Core user interface accessed in this way is called the Web Interface. It is assumed that a network connection has been set up from a management computer to the management Ethernet interface, as described in Section 6.1, Management Computer Connection.

Connect By Browsing to the Management Interface Address

Using a standard web browser, enter the IP address of the If1 interface, For example, 192.168.1.1 as shown below.

Troubleshooting

If there is no response from cOS Core and the reason is not clear, refer to the checklist in Section 6.6, Setup Troubleshooting .

The cOS Core Self-signed Certificate

When responding to the first https:// request in a browser session, cOS Core will send a self-signed certificate to the browser. All browsers will automatically flag this self-signed certificate as posing a potential security risk. In the latest Microsoft browser, the following error message will be displayed in the browser window.

The browser should now be told to accept the Clavister certificate by choosing the option to continue.

The Login Dialog

cOS Core will next respond like a web server with the initial login dialog page, as shown below.

The available Web Interface language options are selectable at the bottom of this dialog. This defaults to the language set for the browser if cOS Core supports that language.

Enter the administrator username as admin and use the default password admin.

Starting the Setup Wizard

After logging in for the first time, the Web Interface will appear and the cOS Core setup wizard should begin automatically as a popup window. If the wizard is blocked by the browser, it can be started manually by pressing the Setup Wizard button in the Web Interface toolbar (shown below).

Once the wizard is started, the first dialog displayed is the wizard welcome screen which is shown below.

Canceling the Wizard

The setup wizard can be canceled at any point before the final Activate screen and run again by choosing the Setup Wizard option from the Web Interface toolbar. Once any configuration changes have been made and activated, either through the wizard, Web Interface or CLI, then the wizard cannot be run since the wizard requires that cOS Core has the factory defaults.

The Wizard Assumes Internet Access will be Configured

The wizard assumes that Internet access will be configured. If this is not the case, for example if the firewall is being used in Transparent Mode between two internal networks, then the configuration setup is best done with individual Web Interface steps or through the CLI instead of through the wizard, and this is described in subsequent sections.

Advantages of the Wizard

The wizard makes setup easier because it automates what would otherwise be a more complex set of individual setup steps. It also reminds the administrator to perform important tasks such as setting the date and time and configuring a log server.

The steps that the wizard goes through after the initial welcome screen are listed next.

Wizard step 1: Enter a new admin password and optionally change the username

The first step in setup with the wizard is to enter a new password for the admin user. The admin username can also be changed if required, as shown in the screenshot below.

The Enforce Strong Passwords option is present in cOS Core versions from 11.05 onwards. This is a global setting that will enforce the listed strong passwords rules for all users in any local user database in the configuration. If required, this option can be disabled later. However, it is recommended to leave this option enabled, which means that the default admin password must be changed to a conforming strong password before the wizard can move on to the next step.

Note that restoring cOS Core to factory defaults will restore the original admin/admin credential combination for management access.

Wizard step 2: Set the date and time

Many cOS Core functions rely on an accurate date and time, so it is important that this is set correctly in the fields shown below. The default time zone location is ClavisterHQ which means the default location and time zone will be Stockholm. If this is not correct it should be changed to another location and timezone using the drop-down list.

Wizard step 3: Select transparent mode interfaces

This step allows any transparent mode interfaces to be set up. If no transparent mode interfaces are required, leave this dialog in the default Normal Mode and go to the next step. Transparent mode interfaces can be configured at any time later, outside of the wizard.

Wizard step 4: Select the WAN interface

Next, you will be asked for the WAN interface that will be used to connect to your ISP for Internet access.

Wizard step 5: Select the WAN interface settings

This step selects how the WAN connection to the Internet will function. It can be one of Manual configuration, DHCP, PPPoE or PPTP as shown below.

These four different connection options are discussed next in the following subsections 5A to 5D.

Wizard step 6: DHCP server settings

If the firewall is to function as a DHCP server, it can be enabled here in the wizard on a particular interface or configured later.

For example, the private IPv4 address range might be specified as 192.168.1.50 - 192.168.1.150 with a netmask of 255.255.255.0.

For the default gateway, it is recommended to specify the IPv4 address assigned to the internal network interface. The DNS server specified should be the DNS supplied by an ISP.

Wizard step 7: Helper server settings

Optional NTP and Syslog servers can be enabled here in the wizard or configured later. Network Time Protocol servers keep the system date and time accurate. Syslog servers can be used to receive and store log messages sent by cOS Core.

When specifying a hostname as a server instead of an IP address, the hostname should be prefixed with the string dns:. For example, the hostname host1.company.com should be entered as dns:host1.company.com.

Wizard step 8: Activate setup

The final step is to activate the setup by pressing the Activate button. After this step the Web Interface returns to its normal appearance and the administrator can continue to configure the system.

Running the Wizard Again

Once the wizard has been successfully finished and activated, it cannot be run again. The exception to this is if the firewall has its factory defaults restored in which case it will behave as though it were being started for the first time.

A Valid License Should Be Installed

Lastly, a valid license should be installed to remove the cOS Core 2 hour demo mode limitation. Without a license installed, cOS Core will have full functionality during the 2 hour period following startup (except for subscription based features), but after that only management access will be possible. Installing a license is described in Section 6.5, Installing a License.

This section describes initial cOS Core configuration performed directly through the Web Interface, without using the setup wizard. Configuration is done as a series of individual steps, giving the administrator more direct control over the process. Even if the wizard is used, this section can also be read as a good introduction to using the Web Interface for configuring key aspects of cOS Core.

Ethernet Interfaces

The physical connection of external networks to the firewall is through the various Ethernet interfaces which are provided by the hardware platform. In a virtual environment, these are the virtual interfaces provided by the hypervisor. On first-time startup, cOS Core scans for these interfaces and determines which are available and allocates their names. The first interface detected in the scan always becomes the initial default management interface and this cannot be changed beforehand.

All cOS Core interfaces are logically equal for cOS Core and although their physical capabilities may be different, any interface can perform any logical function. With cOS Core under KVM, the virtual If1 interface is always the default management interface. Assuming the normal KVM total of 3 virtual interfaces, the other two virtual interfaces will automatically be given the names If2 and If3 by cOS Core. For this section, we will assume that the If2 interface will be used for connection to the public Internet and the If1 interface will also be used for connection to a protected, local network.

Changing the admin Password

It is strongly recommended to change the password of the admin user as the first task in manual cOS Core setup. This is done by first selecting the System option from the Web Interface toolbar and then Local User Databases from the navigation pane to display the local user database list, as shown below.

Next, select AdminUsers to display the contents of this predefined database.

Select the Users option for the database to display a list of users and then select the default user Admin to open a dialog to change its password.

By default, using a strong admin password will be enforced meaning that the new password must comply with a set of strong password conventions. Activating configuration changes will not be possible while the password does not comply. The only way around this is to first turn off the strong password policy in the configuration but this is not recommended.

Setting the Date and Time

Many cOS Core functions rely on an accurate date and time, so it is important that this is set correctly. To do this, select System > Device > Date and Time. The current system time is displayed and this can be changed by selecting the date and time fields then manually entering the desired figures. Pressing the Set button will then set the time to the entered values.

Also choose the correct time zone from the Location drop-down list. The default location is ClavisterHQ which is Stockholm time.

Alternatively, the Synchronize button can be pressed to get the current date and time from the configured Network Time Protocol (NTP) server. In the default configuration, Clavister's own NTP server is automatically configured. However, accessing this server requires Internet access.

Configuring a custom NTP server configuration is shown below.

Once the values are set correctly, we can press the OK button to save the values while we move on to more steps in cOS Core configuration. Although changed values like this are saved by cOS Core, they do not become active until the entire saved configuration becomes the current and active configuration. We will look at how to do this next.

Activating Configuration Changes

To activate any cOS Core configuration changes made so far, select the Save and Activate option from the Configuration menu (this procedure is also referred to as deploying a configuration).

A dialog is then presented to confirm that the new configuration is to become the running configuration.

After clicking OK, cOS Core reconfiguration will take place and, after a short delay, the Web Interface will try and connect again to the firewall.

If no reconnection is detected by cOS Core within 30 seconds (this length of time is a setting that can be changed) then cOS Core will revert back to the original configuration. This is to ensure that the new configuration does not accidentally lock out the administrator. After reconfiguration and successful reconnection, a success message is displayed indicating successful reconfiguration.

Reconfiguration is a process that the cOS Core administrator may initiate often. Normally, reconfiguration takes a brief amount of time and causes only a slight delay in traffic throughput. Active user connections through the firewall should rarely be lost.

Automatic Logout

If there is no activity through the Web Interface for a period of time (the default is 15 minutes), cOS Core will automatically log the user out. If they log back in through the same web browser session then they will return to the point they were at before the logout occurred and no saved (but not yet activated) changes are lost.

Setting Up Internet Access

Next, we shall look at how to set up public Internet access with the CLI. There are four options for setting up access which are listed below and then described in detail.

A. Static - manual configuration.

B. DHCP - automatic configuration.

C. PPPoE setup

D. PPTP setup

The individual manual steps to configure these connection alternatives with the Web Interface are discussed next.

A. Static - manual configuration

Manual configuration means that there will be a direct connection to the ISP and all the relevant IP addresses for the connecting interface are fixed values provided by the ISP which are entered into cOS Core manually.

The initial step is to set up a number of IPv4 address objects in the cOS Core Address Book. Let us assume that the interface used for Internet connection is to be If2 and that the static IPv4 address for this interface is to be 203.0.113.35, the ISP's gateway IPv4 address is 203.0.113.1, and the network to which they both belong is 203.0.113.0/24.

Now, add the gateway IP4 Address object using the address book name wan_gw and assign it the IPv4 address 203.0.113.1. The ISP's gateway is the first router hop towards the public Internet from the firewall. Go to Objects > Address Book in the Web Interface.

The current contents of the address book will be listed and will contain a number of predefined objects automatically created by cOS Core after it scans the interfaces for the first time. The screenshot below shows the initial address book for the firewall.

All the Ethernet interface related address objects are gathered together in an Address Book Folder called InterfaceAddresses. By clicking on this folder, it will be opened and the individual address objects it contains can be viewed. Predefined addresses in the folder are shown below.

On initial startup, two IPv4 address objects are created automatically for each interface detected by cOS Core. One IPv4 address object is named by combining the physical interface name with the suffix "_ip" and this is used for the IPv4 address assigned to that interface. The other address object is named by combining the interface name with the suffix "_net" and this is the network to which the interface belongs.

Now click the Add button at the top left of the list and choose the IP4 Address option to add a new address to the folder.

Enter the details of the object into the properties fields for the IP4 Address object. Below, the IPv4 address 203.0.113.1 has been entered for the address object called wan_gw. This is the IP of the ISP's router which acts as the gateway to the public Internet.

Click the OK button to save the values entered.

Then set up If2_ip to be 203.0.113.35. This is the IPv4 address of the If2 interface which will connect to the ISP's gateway.

Lastly, set the IP4 Address object If2_net to be 203.0.113.0/24. Both the address objects If2_ip and wan_gw must belong to the same network in order for the interface to communicate with the ISP.

Together, these three IPv4 address objects will be used to configure the interface connected to the Internet which, in this example, is If2. Select Network > Interfaces and VPN > Ethernet to display a list of the physical interfaces and address book objects assigned to them. The first lines of the default interface list are shown below.

Click on the interface in the list which is to be connected to the Internet. The properties for this interface will now appear and the settings can be changed including the default gateway.

Press OK to save the changes. Although changes are remembered by cOS Core, the changed configuration is not yet activated and won't be activated until cOS Core is told explicitly to use the changed configuration.

Remember that DHCP should not be enabled when using static IP addresses and also that the IP address of the Default Gateway (which is the ISP's router) must be specified. As explained in more detail later, specifying the Default Gateway also has the additional effect of automatically adding a route for the gateway in the cOS Core routing table.

At this point, the connection to the Internet is configured but no traffic can flow to or from the Internet since all traffic needs a minimum of the following two cOS Core configuration objects to exist before it can flow through the firewall :

An IP policy therefore needs to be defined that will allow traffic from clients to the Internet. In this case, that web browsing is to be allowed from the protected private network If1_net connected to the interface If1.

To do this, first go to Policies > Firewalling > Main IP Rules. The main IP rule set will now be displayed.

To add a new IP policy, press the Add button and select IP Policy from the menu.

The properties for the new object will appear. In this example, the policy will be called lan_to_wan. The Service is set to http-all which is suitable for most web browsing (it allows both HTTP and HTTPS connections).

The destination network is specified as the predefined IP4 Address object all-nets. This is used since it cannot be known in advance to which IP address web browsing will be directed and all-nets allows browsing to any IP address. IP rule sets are processed in a top down fashion, with the search ending at the first matching entry. An all-nets entry like this should be placed towards the end of the rule set since other rules with narrower destination addresses should trigger first.

In addition to entering the above for the policy, the Source Translation should be set to NAT and the Address Action left as Outgoing Interface IP. Note that the default source translation value for an IP policy is Auto and this would also provide NAT translation between a private and public IP address but NAT is specified explicitly in this section for clarity.

By using NAT, cOS Core will use the destination interface's IP address as the source IP. This means that external hosts will send their responses back to the interface IP and cOS Core will automatically forward the traffic back to the originating local host. Only the outgoing interface therefore needs to have a public IPv4 address and the internal network topology is hidden.

For web browsing, public DNS lookup also needs to be allowed in order to resolve URLs into IP addresses. The service http-all does not include the DNS protocol so a similar IP rule set entry that allows this is needed. This could be done with a single IP policy that uses a custom service which combines the HTTP and DNS protocols but the recommended method is to create an entirely new IP set entry that specifies the service as dns-all. This method provides the most clarity when the configuration is examined for any problems. The screenshot below shows a new IP policy called lan_to_wan_dns being created to allow DNS.

As was done for HTTP, NAT should also be enabled with this IP policy so all DNS queries are sent out by cOS Core with the outgoing interface's IP address as the source IP.

For the Internet connection to work, a route also needs to be defined so that cOS Core knows on which interface the web browsing traffic should leave the firewall. This route will define the interface where the network all-nets (in other words, any network) will be found. If the default main routing table is opened by going to Network > Routing > Routing Tables > main, the route needed should appear as shown below.

This required all-nets route is, in fact, added automatically after specifying the Default Gateway for a particular Ethernet interface and this was done earlier when setting up the required IP4 Address objects.

As part of the setup, it is also recommended that at least one DNS server is also defined in cOS Core. This DNS server or servers (a maximum of three can be configured) will be used when cOS Core itself needs to resolve URLs which is the case when a URL is specified in a configuration object instead of an IP address. It is also important for certificate handling

Assume an IPv4 address object called wan_dns1 has already been defined in the address book and this is the address for the first DNS server. By choosing System > Device > DNS, the DNS server dialog will open and this object from the address book can be assigned as the first server.

B. DHCP - automatic configuration

All the required IP addresses for Internet connection can, alternatively, be automatically retrieved from an ISP's DHCP server by enabling the DHCP Client option for the interface connected to the ISP. This option is enabled by first selecting Network > Interfaces and VPN > Ethernet to display a list of all the interfaces.

Click the If2 interface in the list to display its properties and select the option to enable the interface as a DHCP client.

Usually, a DHCP Host Name does not need to be specified but can sometimes be used by an ISP to uniquely identify this firewall as a particular DHCP client to the ISP's DHCP server.

On connection to the ISP, all required IP addresses are retrieved automatically from the ISP via DHCP and cOS Core automatically sets the relevant address objects in the address book with this information.

For cOS Core to know on which interface to find the public Internet, a route has to be added to the main cOS Core routing table which specifies that the network all-nets can be found on the interface connected to the ISP and this route must also have the correct Default Gateway IP address specified. This all-nets route is added automatically by cOS Core during the DHCP address retrieval process.

After all IP addresses are set via DHCP and an all-nets route is added, the connection to the Internet is configured but no traffic can flow to or from the Internet since there is no IP rule set entry defined that allows it. As was done in the previous option (A) above, we must therefore define an IP policy that will allow traffic from the source network If1_net and source interface If1 to flow to the destination network all-nets and the destination interface If2.

C. PPPoE setup

For PPPoE connection, we must create a PPPoE tunnel interface associated with the physical Ethernet interface. Assume that the physical interface is If2 and the PPPoE tunnel object created is called wan_pppoe. Go to Network > Interfaces and VPN > PPPoE and select Add > PPPoE Tunnel. These values can now be entered into the PPPoE Tunnel properties dialog.

An ISP will supply the correct values for pppoe_username and pppoe_password in the dialog above.

The PPPoE tunnel interface can now be treated exactly like a physical interface by the policies defined in cOS Core rule sets.

There also has to be a route associated with the PPPoE tunnel to allow traffic to flow through it, and this is automatically created in the main routing table when the tunnel is defined. If we go to Network > Routing > Routing Tables > main we can see this route.

If the PPPoE tunnel object is deleted, this route is also automatically deleted.

At this point, no traffic can flow through the tunnel since there is no IP rule set entry defined that allows it. As was done in option A above, we must define an IP policy that will allow traffic from the source network If1_net and source interface If1 to flow to the destination network all-nets and the destination interface. Here, the destination interface is the PPPoE tunnel that has been defined.

D. PPTP setup

For PPTP connections, a PPTP client tunnel interface object needs to be created. Let us assume that the PPTP tunnel will be called wan_pptp with a remote endpoint 203.0.113.1 which has been defined as the IP4 Address object pptp_endpoint. Go to Network > Interfaces and VPN > PPTP/L2TP Clients and select Add > PPTP/L2TP Client. The values can now be entered into the properties dialog and the PPTP option should be selected.

An ISP will supply the correct values for pptp_username, pptp_password and the remote endpoint. An interface is not specified when defining the tunnel because this is determined by cOS Core looking up the Remote Endpoint IP address in its routing tables.

The PPTP client tunnel interface can now be treated exactly like a physical interface by the policies defined in cOS Core rule sets.

There also has to be an associated route with the PPTP tunnel to allow traffic to flow through it, and this is automatically created in the main routing table when the tunnel is defined. The destination network for this route is the Remote Network specified for the tunnel and for the public Internet this should be all-nets.

If we go to Network > Routing > Routing Tables > main we can see this route.

If the PPTP tunnel object is deleted, this route is also automatically deleted.

At this point, no traffic can flow through the tunnel since there is no IP rule entry defined that allows it. As was done in option A above, we must define an IP policy that will allow traffic from a designated source network and source interface (in this example, the network If1_net and interface If1) to flow to the destination network all-nets and the destination interface which is the PPTP tunnel that has been defined.

DHCP Server Setup

If the firewall is to act as a DHCP server then this can be set up in the following way:

First, create an IP4 Address object which defines the address range to be handed out. Here, it is assumed that this has the name dhcp_range. It is also assumed that another IP4 Address object dhcp_netmask has been created which specifies the netmask.

We now create a DHCP server object called my_dhcp_server which will only be available on the If1 interface. To do this, go to Network > Network Services > DHCP Servers and select Add > DHCP Server. The server properties can now be specified.

An example IP pool range might be 196.168.1.10 - 192.168.1.20 with a netmask of 255.255.0.0.

In addition, it is important to specify the Default gateway for the server. This will be handed out to DHCP clients on the internal networks so that they know where to find the public Internet. The default gateway is always the IPv4 address of the interface on which the DHCP server is configured, in this case, If1_ip. To set the default gateway, select the Options tab.

Also in the Options tab, we should specify the DNS address which is handed out with DHCP leases. This could be set, for example, to be the IPv4 address object dns1_address.

Syslog Server Setup

Although logging may be enabled, no log messages are captured unless at least one log server is set up to receive them and this is configured in cOS Core. Syslog is one of the most common server types.

First we create an IP4 Address object called, for example, syslog_ip which is set to the IPv4 address of the server. We then configure the sending of log messages to a Syslog server from cOS Core by selecting System > Device > Log and Event Receivers and then choosing Add > Syslog Receiver.

The Syslog server properties dialog will now appear. We give the server a name, for example my_syslog, and specify its IPv4 address as the syslog_ip object.

Allowing ICMP Ping Requests

As a further example of setting up IP rule set entries, it can be very useful to allow ICMP Ping requests to flow through the firewall. As discussed earlier, the cOS Core will drop any traffic unless a rule set entry explicitly allows it. Let us suppose that we wish to allow the pinging of external hosts with the ICMP protocol by computers on the internal network G1_net.

There can be several IP rule sets defined in cOS Core but there is only one rule set defined by default and this is called main. To add an entry to it, first select Policies > Firewalling > Main IP Rules.

The main rule set list contents are now displayed. Press the Add button and select IP Policy.

The properties for a new IP policy will appear and we can add the entry, in this case called allow_ping_outbound.

As with previous policy definitions, NAT should also be enabled if the protected local hosts have private IPv4 addresses. The ICMP requests will then be sent out from the firewall with the IP address of the interface connected to the ISP as the source interface. Responding hosts will send back ICMP responses to this single IP and cOS Core will then forward the response to the correct private IPv4 address.

Adding a Drop All Policy

The top-down nature of the IP rule set scanning has already been discussed earlier. If no matching entry is found for a new connection then the default rule is triggered. This entry is hidden and cannot be changed. Its action is to drop all such traffic as well as generate a log message for the drop.

In order to gain control over the logging of dropped traffic, it is recommended to create a drop all policy as the last entry in the main IP rule set. This policy will have the source and destination network set to all-nets and the source and destination interface set to any. The service should be set to all_services in order to capture all types of traffic.

Logging is enabled by default for an IP rule set entry which means that a log message will be sent to all configured log servers whenever the entry triggers. Only log events that have a specified severity or above will be sent. The administrator can choose the minimum severity for log messages in each IP rule set entry, as shown below.

If this IP policy were the only one defined, the main IP rule set listing would be as shown below.

A Valid License Must Be Installed

If not done already, a valid license should be installed to remove the cOS Core two hour demo mode limitation. Without a license installed, cOS Core will have full functionality during the two hour period following startup, but after that, only management access will be possible. Installing a license is described in Section 6.5, Installing a License.

This chapter describes the setup steps using CLI commands instead of the setup wizard.

The CLI is accessible using either one of two methods:

Confirming the Connection

Once connection is made to the CLI, pressing the Enter key will cause cOS Core to respond. The response will be a normal CLI prompt if connecting directly through the local console and a username/password combination will not be required (a password for this console can be set later).

Device:/> 

If connecting remotely through an SSH (Secure Shell) client, an administration username/password must first be entered and the initial default values for these are username admin and password admin. When these are accepted by cOS Core, a normal CLI prompt will appear and CLI commands can be entered.

Manually Assigning a Management Interface IP Address

By default, cOS Core will enable a DHCP client on all Ethernet interfaces, including the default management interface If1. If an external DHCP server is not used to assign an IP address to the management interface, it must be manually assigned using CLI commands entered via the local cOS Core console. First, the DHCP client must be disabled:

Device:/> set Interface Ethernet If1 DHCPEnabled=No

This same command form can be used to disable DHCP on another interface, if required. For example:

Device:/> set Interface Ethernet If2 DHCPEnabled=No

Next, assign an IP address to the management interface. For example:

Device:/> set Address IP4Address InterfaceAddresses/If1_ip
			Address=192.168.1.1

This is followed by setting a network for the management interface. For example:

Device:/> set Address IP4Address InterfaceAddresses/If1_net
			Address=192.168.1.0/24

This is the IP address and network that can be now be used for both CLI and WebUI management access over a network to the If1 interface. This section will continue with manual CLI configuration.

Changing the admin Account Password

It is strongly recommended to change the password of the admin user as the first task in manual cOS Core setup. To do this, use the set command to change the current CLI object category (also referred to as the context) to be the LocalUserDatabase called AdminUsers.

Device:/> cc LocalUserDatabase AdminUsers
Device:/AdminUsers> 

Now set a new password for the administrator which is difficult to guess. For example:

Device:/AdminUsers> set User admin Password=Mynew*pass99

The next step is to return the CLI to the default CLI context:

Device:/AdminUsers> cc
Device:/> 

By default, using a strong admin password will be enforced meaning that the new password must comply with a set of strong password conventions. Activating configuration changes will not be possible while the password does not comply. The only way around this is to first turn off the strong password policy in the configuration but this is not recommended.

Setting the Date and Time

Many cOS Core functions, such as event logging and certificate handling, rely on an accurate date and time. It is therefore important that this is set correctly using the time command. A typical usage of this command might be:

Device:/> time -set 2017-06-24 14:43:00

Notice that the date is entered in yyyy-mm-dd format and the time is stated in 24 hour hh:mm:ss format.

Ethernet Interfaces

The connection of external networks to the firewall is via the various Ethernet interfaces which are provided by the hardware platform. On first-time startup, cOS Core determines which interfaces are available and allocates their logical names. One interface is chosen as the initial default management interface and this can only be changed after initial startup.

All cOS Core interfaces are logically equal for cOS Core and although their physical capabilities may be different, any interface can perform any logical function. However, the If1 interface is the default management interface. The other interfaces can be used as required. For this section, it is assumed that the If2 interface will be used for connection to the public Internet and the If1 interface will also be used for connection to a protected, local client network.

Setting Up Internet Access

Next, we shall look at how to set up public Internet access with the CLI. There are four options for setting up access which are listed below and then described in detail.

A. Static - manual configuration.

B. DHCP - automatic configuration.

C. PPPoE setup.

D. PPTP setup.

The individual manual steps to configure these connection alternatives with the CLI are discussed next.

A. Static - manual configuration

We first must set or create a number of IPv4 address objects. It is assumed here that the interface used for Internet connection is If2, the ISP gateway IPv4 address is 203.0.113.1, the IPv4 address for the connecting interface will be 203.0.113.35 and the network to which they both belong is 203.0.113.0/24.

First, add the gateway IPv4 address object if it does not already exist:

Device:/> add Address IP4Address wan_gw Address=203.0.113.1

This is the address of the ISP's gateway which is the first router hop towards the public Internet. If this IP object already exists, it can be given the IP address with the command:

Device:/> set Address IP4Address wan_gw Address=203.0.113.1

Now, set the gateway on the If2. interface which is connected to the ISP:

Device:/> set Interface Ethernet If2 DefaultGateway=wan_gw

Next, set the IP address of the If2_ip address object which is the IP assigned to the interface:

Device:/> set Address IP4Address InterfaceAddresses/If2_ip
			Address=203.0.113.35

Now, set the IP object If2_net. which will be the IP network of the connecting interface:

Device:/> set Address IP4Address InterfaceAddresses/If2_net
			Address=203.0.113.0/24

It is recommended to verify the properties of the If2. interface using the following command:

Device:/> show Interface Ethernet If2

The typical output from this will be similar to the following:

                   Property  Value
 --------------------------  --------------------------
                      Name:  If2
                        IP:  InterfaceAddresses/If2_ip
                   Network:  InterfaceAddresses/If2_net
            DefaultGateway:  wan_gw
                 Broadcast:  203.0.113.255                  
                 PrivateIP:  <empty>
                     NOCHB:  <empty>
                       MTU:  1500
                    Metric:  100
               DHCPEnabled:  No
            EthernetDevice:  0:If2  1:<empty>
           AutoSwitchRoute:  No
 AutoInterfaceNetworkRoute:  Yes
   AutoDefaultGatewayRoute:  Yes
   ReceiveMulticastTraffic:  Auto
      MemberOfRoutingTable:  All
                  Comments:  <empty>

Setting the default gateway on the interface has the additional effect that cOS Core automatically creates a route in the default main routing table that has the network all-nets routed on the interface. This means that we do not need to explicitly create this route.

Even though an all-nets route is automatically added, no traffic can flow without the addition of an IP rule set entry which explicitly allows traffic to flow. Let us assume we want to allow web browsing from the protected network If1_net which is connected to the interface If1.

The following command will add an IP policy called lan_to_wan to allow traffic from If1_net through to the public Internet:

Device:/> add IPPolicy Name=lan_to_wan
			SourceInterface=If1
			SourceNetwork=InterfaceAddresses/If1_net
			DestinationInterface=If2
			DestinationNetwork=all-nets
			Service=http-all
			Action=Allow

IP policies have a default value of Auto for the type of source translation. This means that if the source is a private IPv4 address and the destination is a public address, NAT will be performed automatically using the IP address of the outgoing interface as the new source address. Therefore the above IP policy will work both for connection to another private IP address or to public addresses on the Internet.

Instead of relying on the Auto option, this section will specify NAT translation explicitly for clarity. The above IP policy with explicit NAT translation becomes the following:

Device:/main> add IPPolicy Name=lan_to_wan
			SourceInterface=If1
			SourceNetwork=InterfaceAddresses/If1_net
			DestinationInterface=If2
			DestinationNetwork=all-nets
			Service=http-all
			Action=Allow
			SourceAddressTranslation=NAT
			NATSourceAddressAction=OutgoingInterfaceIP

Specifying NATSourceAddressAction=OutgoingInterfaceIP is not necessary as this is the default value but it is included here for clarity.

The service used is http-all which will allow web browsing but does not include the DNS protocol to resolve URLs into IP addresses. To solve this problem, a custom service could be used in the above which combines http-all with the dns-all service. However, the recommended method, which provides the most clarity to a configuration, is to create a separate IP policy for DNS:

Device:/main> add IPPolicy Name=lan_to_wan_dns
			SourceInterface=If1
			SourceNetwork=InterfaceAddresses/If1_net
			DestinationInterface=If2
			DestinationNetwork=all-nets
			Service=dns-all
			Action=Allow
			SourceAddressTranslation=NAT
			NATSourceAddressAction=OutgoingInterfaceIP

It is recommended that at least one DNS server is also defined in cOS Core. This DNS server or servers (a maximum of three can be configured) will be used when cOS Core itself needs to resolve URLs which will be the case when a URL is specified in a configuration instead of an IP address. If we assume an IP address object called dns1_address has already been defined for the first DNS server, the command to specify the first DNS server is:

Device:/> set DNS DNSServer1=dns1_address

Assuming a second IP object called dns2_address has been defined, the second DNS server is specified with:

Device:/> set DNS DNSServer2=dns2_address

B. DHCP - automatic configuration

Alternatively, all required IP addresses can be automatically retrieved from the ISP's DHCP server by enabling DHCP on the interface connected to the ISP.

If the interface on which DHCP is to be enabled is If2, then the command is:

Device:/> set Interface Ethernet If2 DHCPEnabled=Yes

Once the required IP addresses are retrieved with DHCP, cOS Core automatically sets the relevant address objects in the address book with this information.

For cOS Core to know on which interface to find the public Internet, a route has to be added to the main cOS Core routing table which specifies that the network all-nets can be found on the interface connected to the ISP and this route must also have the correct Default Gateway IP address specified. This all-nets route is added automatically by cOS Core during the DHCP address retrieval process. Automatic route generation is a setting for each interface that can be manually enabled and disabled.

After all IP addresses are set via DHCP and an all-nets route is added, the connection to the Internet is configured but no traffic can flow to or from the Internet since there is no IP rule set entry defined that allows it. As was done in the previous option (A) above, we must therefore manually define an IP policy that will allow traffic from a designated source network and source interface (in this example, the network If1_net and interface If1) to flow to the destination network all-nets and the destination interface If2.

C. PPPoE setup

For PPPoE connection, create the PPPoE tunnel interface on the interface connected to the ISP. The interface If2. is assumed to be connected to the ISP in the command shown below which creates a PPPoE tunnel object called wan_ppoe:

Device:/> add Interface PPPoETunnel wan_ppoe
			EthernetInterface=If2
			username=pppoe_username
			Password=pppoe_password
			Network=all-nets

The ISP will supply the correct values for pppoe_username and pppoe_password in the dialog above.

The PPPoE tunnel interface can now be treated exactly like a physical interface by the policies defined in cOS Core rule sets.

There also has to be a route associated with the PPPoE tunnel to allow traffic to flow through it and this is automatically created in the main routing table when the tunnel is defined. If the PPPoE tunnel object is deleted, this route is also automatically deleted.

At this point, no traffic can flow through the tunnel since there is no IP rule set entry defined that allows it. As was done in option A above, we must define an IP policy that will allow traffic from a designated source network and source interface (in this example, the network If1_net and interface If1) to flow to the destination network all-nets and the destination interface which is the PPPoE tunnel that has been defined.

D. PPTP setup

For PPTP connection, first create the PPTP tunnel interface. It is assumed below that we will create a PPTP tunnel object called wan_pptp with the remote endpoint 203.0.113.1:

Device:/> add Interface L2TPClient wan_pptp
			Network=all-nets
			Username=pptp_username
			Password=pptp_password
			RemoteEndpoint=203.0.113.1
			TunnelProtocol=PPTP

Your ISP will supply the correct values for pptp_username, pptp_password and the remote endpoint.

Your ISP will supply the correct values for pptp_username, pptp_password and the remote endpoint. An interface is not specified when defining the tunnel because this is determined by cOS Core looking up the Remote Endpoint IP address in its routing tables.

The PPTP client tunnel interface can now be treated exactly like a physical interface by the policies defined in cOS Core rule sets.

There also has to be an associated route with the PPTP tunnel to allow traffic to flow through it, and this is automatically created in the main routing table when the tunnel is defined. The destination network for this route is the Remote Network specified for the tunnel and for the public Internet this should be all-nets.

As with all automatically added routes, if the PPTP tunnel object is deleted then this route is also automatically deleted.

At this point, no traffic can flow through the tunnel since there is no IP rule set entry defined that allows it. As was done in option A above, we must define an IP policy that will allow traffic from a designated source network and source interface (in this example, the network If1_net and interface If1) to flow to the destination network all-nets and the destination interface which is the PPTP tunnel that has been defined.

Activating and Committing Changes

After any changes are made to a cOS Core configuration, they will be saved as a new configuration but will not yet be activated. To activate all the configuration changes made since the last activation of a new configuration, the following command must be issued:

Device:/> activate

Although the new configuration is now activated, it does not become permanently activated until the following command is issued within 30 seconds following the activate:

Device:/> commit

The reason for two commands is to prevent a configuration accidentally locking out the administrator. If a lock-out occurs then the second command will not be received and cOS Core will revert back to the original configuration after the 30 second time period (this time period is a setting that can be changed).

If the admin account password has not been changed earlier to a strong password and strong passwords are enabled (by default, they are) then activating configuration changes will not be allowed by cOS Core. The solution to this is, before activation, either to change the admin account password to a strong one or turn off strong passwords with the following command:

Device:/> set Settings MiscSettings EnforceStrongPasswords=No

If activation fails because of a weak password, the old admin password must be reset anyway, even if the new value is the same as the old.

DHCP Server Setup

If the firewall is to act as a DHCP server then this can be set up in the following way:

First define an IPv4 address object which has the address range that can be handed out. Here, we will use the IPv4 range 192.168.1.10 - 192.168.1.20 as an example and this will be made available on the If1 interface which is connected to the protected internal network If1_net.

Device:/> add Address IP4Address dhcp_range
			Address=192.168.1.10-192.168.1.20

The DHCP server is then configured with this IP address object on the appropriate interface. In this case, we will call the created DHCP server object my_dhcp_server.

Device:/> add DHCPServer my_dhcp_server
			IPAddressPool=dhcp_range
			Interface=If1
			Netmask=255.255.255.0
			DefaultGateway=InterfaceAddresses/If1_ip
			DNS1=dns1_address

It is important to specify the default gateway for the DHCP server since this will be handed out to DHCP clients on the internal network so that they know where to find the public Internet. The default gateway is always the IP address of the interface on which the DHCP server is configured. In this case, If1_ip.

NTP Server Setup

Network Time Protocol (NTP) servers can optionally be configured to maintain the accuracy of the system date and time. Suppose that synchronization is to be setup with the two NTP servers at hostname pool.ntp.org and IPv4 address 203.0.113.5.

First, an FQDNAddress object needs to set up for the hostname:

Device:/> add Address FQDNAddress ts1_fqdn Address=pool.ntp.org

Next, set the servers to use for date and time synchronization:

Device:/> set DateTime TimeSyncEnable=Yes
		TimeSyncServer1=ts1_fqdn
		TimeSyncServer2=203.0.113.5

Syslog Server Setup

Although logging may be enabled, no log messages are captured unless a server is set up to receive them and Syslog is the most common server type. If the Syslog server's address is 192.0.2.10 then the command to create a log receiver object called my_syslog which enables logging is:

Device:/> add LogReceiverSyslog my_syslog IPAddress=192.0.2.10

Allowing ICMP Ping Requests

As a further example of setting up IP rule set entries, it can be useful to allow ICMP Ping requests to flow through the firewall. As discussed earlier, cOS Core will drop any traffic unless a rule set entry explicitly allows it. Let us suppose that we wish to allow the pinging of external hosts with the ICMP protocol by computers on the internal If1_net network. The commands to allow this are as follows.

Add an IP policy called allow_ping_outbound to allow ICMP pings to pass:

Device:/> add IPPolicy Name=allow_ping_outbound
			SourceInterface=If1
			SourceNetwork=InterfaceAddresses/If1_net
			DestinationInterface=If2
			DestinationNetwork=all-nets
			Service=ping-outbound
			Action=Allow
			SourceAddressTranslation=NAT
			NATSourceAddressAction=OutgoingInterfaceIP

This IP policy uses NAT and this is necessary if the protected local hosts have private IPv4 addresses. The ICMP requests will be sent out from the firewall with the IP address of the interface connected to the ISP as the source interface. Responding hosts will send back ICMP responses to this single IP and cOS Core will then forward the response to the correct private IP address.

Adding a Drop All Policy

Scanning of IP rule sets is done in a top-down fashion. If no matching rule set entry is found for a new connection then the default rule is triggered. This rule is hidden and cannot be changed and its action is to drop all such traffic as well as generate a log message for the drop.

In order to gain control over the logging of dropped traffic, it is recommended to create a drop all policy as the last entry in the main IP rule set. This policy will have the source and destination network set to all-nets and the source and destination interface set to any. The service should be set to all_services in order to capture all types of traffic.

The following IP policy will drop all remaining traffic as well as turning off logging for that traffic:

Device:/main> add IPPolicy Name=drop_all
			SourceInterface=any
			SourceNetwork=any
			DestinationInterface=any
			DestinationNetwork=all-nets
			Service=all_services
			Action=Deny
			LogEnabled=No

A Valid License Should Be Installed

Lastly, a valid license should be installed to remove the cOS Core 2 hour demo mode limitation. Without a license installed, cOS Core will have full functionality during the 2 hour period following startup (except for subscription based features), but after that only management access will be possible. Installing a license is described in Section 6.5, Installing a License.

Each virtual copy of cOS Core running under KVM requires a unique license file to be installed. Without a license, cOS Core will function for only 2 hours from startup in demo mode (demonstration mode). To end demo mode, a valid license file must be installed.

The following should be noted for license installation with cOS Core running in a virtual environment:

Registering a SECaaS License on MyClavister

Before a SECaaS license becomes active, it must first be registered in the relevant MyClavister account. This requires the following steps:

An Older Non-SECaaS License Must First Be Deleted

If an older, non-SECaaS license is already installed, it must be deleted using the command:

Device:/> license -remove

This should be followed by a reconfiguration command:

Device:/> reconf

Installing a SECaaS License

Following registration and the deletion of any non-SECaaS license, a SECaaS license can be installed by automatically downloading it from the license server to cOS Core. To initiate this, enter the following CLI console command either remotely with SSH or using the local console:

Device:/> license -secaas_add <secaas-system-id> <secaas-reg-key>

From cOS Core version 14.00.04 onwards, the above procedure is also possible using the WebUI by going to Status > Maintenance > License and filling in the SECaaS codes then pressing Register.

Note that installation of a SECaaS license along with example CLI console output is also covered by an article in the Clavister Knowledge Base at the following link:

https://kb.clavister.com/336145229

Deleting a SECaaS License

If a SECaaS license is to be deleted, the steps are the following:

License Verification and Updating

Once a SECaaS license is installed, cOS Core will check every 4 hours that the license is valid and also check for any license updates. It does this by contacting the Clavister Service Provider Network (SPN) across the Internet.

If a newer license is found, cOS Core will download it and install it immediately. If verification fails the firewall will enter lockdown mode and only management access will be possible. A verification failure might be caused by license expiry, a faulty license file or a blacklisted license.

Reduced Functionality Mode

If cOS Core with a SECaaS license cannot contact the Clavister SPN for a period of 6 hours, it will enter reduced functionality mode. This mode means that cOS Core operates as before but with the following restrictions:

More information about cOS Core licenses can be found in the cOS Core Administration Guide.

This appendix deals with connection problems that might occur when connecting a management computer to a Clavister NetWall Firewall.

If the management interface does not respond after the firewall has powered up and cOS Core has started, there are a number of simple steps to troubleshoot basic connection problems:

1. Check that the correct interface is being used.

The most obvious problem is that the wrong interface has been used for the initial connection to the management computer. Only the first interface found by cOS Core is activated for the initial connection from a browser after cOS Core starts for the first time.

2. Check that the computer IP is configured correctly.

The second most obvious problem is if the IP address of the management computer running the web browser is not configured correctly.

3. Using the ifstat CLI command.

To investigate a connection problem further, use the KVM console after cOS Core starts. When you press the enter key with the console, cOS Core should respond with the a standard CLI prompt. Now enter the following command once for each interface:

Device:/> ifstat <if-name>

Where <if-name> is the name of the cOS Core management interface. By default this is the KVM If1 interface. This command will display a number of counters for that interface. The ifstat command on its own can list the names of all the KVM interfaces.

If the Input counters in the hardware section of the output are not increasing then the error is likely to be in the cabling. However, it may simply be that the packets are not getting to the firewall in the first place. This can be confirmed with a packet sniffer if it is available.

If the Input counters are increasing, the management interface may not be attached to the correct physical network. There may also be a problem with the routing information in any connected hosts or routers.

4. Using the arpsnoop CLI command.

A final diagnostic test is to try using the console command:

Device:/> arpsnoop -all

This will show the ARP packets being received on the different interfaces and confirm that the correct connections have been made to the correct interfaces.

Upgrades Under KVM

When running under KVM, upgrades of cOS Core are done just as they are on a non-virtualized cOS Core installation, by installing upgrade packages through the normal cOS Core user interfaces. It is not necessary to create a new virtual machine for a new version.

Increasing IPsec Performance with AES-NI

If the underlying hardware platform supports AES-NI acceleration, this can be made use of by cOS Core to significantly accelerate IPsec throughput when AES encryption is used. This acceleration is enabled by default.

If disabled, this feature can be enabled in the Web Interface by going to Network > Interfaces and VPN > Advanced Settings and clicking the checkbox Enable AES-NI acceleration. In the CLI, use the command:

Device:/> set Settings IPsecTunnelSettings AESNIEnable=Yes

After enabling, cOS Core must be rebooted for this option to take effect.

To check if the underlying platform supports AES-NI, use the CLI command:

Device:/> cpuid

If AES-NI is supported, aes will appear in the Feature flags list in the output from the command.