Technical Tip: Configuring DNS servers per SSL VPN Portal

Description
This article describes how to configure DNS servers differently for different user groups (or tunnels), configure it uniquely for each SSL VPN portal and then assign user groups a unique portal.


Solution
Configuring the DNS servers for individual VPN portal can be done only via the CLI

Firmware version from V5.2 onwards.

# config vpn ssl web portal
    edit <portal>
        set dns-server1 <ip4_addr>
        set dns-server2 <ip4_addr>
    end

If IPv6 is used  with the SSL VPN connection, set the IPv6 DNS address as well on the firewall web portal.

# config vpn ssl web portal
    edit <portal>
        set dns-server1 <ip6_addr>
        set dns-server2 <ip6_addr>
    end

Specifying the DNS server settings at the portal level is overriding those at the global level.

If all SSL VPN portals have DNS settings configured, remove the DNS settings at the system level.

# config vpn ssl settings
    unset dns-server1
    unset dns-server2
end

Do it for the IPv6 as well,

# config vpn ssl settings
    unset ipv6-dns-server1
    unset ipv6-dns-server2
end