About Multi-Wan And Dns; Configure A Second External Interface For A Broadband Connection - Watchguard Firebox X15 User Manual

Network Settings

About multi-WAN and DNS

When you configure more than one external interface on your Edge, it is a good idea to enter two DNS server
addresses when you configure DHCP settings for the trusted and optional networks. Some ISPs allow queries
to their DNS servers only if the query comes from that ISP network. If you leave the DNS server information
blank in the trusted network DHCP settings, the Edge continues to use the WAN1 DNS server after it fails over
to WAN2. If the WAN2 IPS does not allow that DNS server, WAN failover does not work. To correct this, enter
the DNS server address for the WAN1 ISP as the primary address. Enter the DNS server address for the WAN2
ISP as the secondary address. When the Edge fails over from WAN1 to WAN2, the Edge queries the DNS server
used by the ISP on WAN1. If it is refused,the Edge uses the secondary DNS server.

Configure a second external interface for a broadband connection

1. If you use a static connection to the Internet, select Manual Configuration from the Configuration
Mode drop-down list.
If you use DHCP to connect to the external network, select DHCP Client from the Configuration Mode
drop-down list.
If you use PPPoE to connect to the Internet, select PPPoE Client from the Configuration Mode drop-
down list.
2. Add the information required for the type of connection you use. For more information, see
ISP uses DHCP,
3. Click Submit.
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If your ISP uses static IP addresses, or If your ISP uses PPPoE.
Firebox X Edge e-Series
If your