Dual ADSL

Jembeck22 · ‎12-23-2008

One of my clients is running a 1800 router with ios 12.2. The client had dual adsl and wished to use one as the primary and the other as a fallback/reduntant line. is this possible and how would i go about this.

Giuseppe Larosa · ‎12-23-2008

Hello Jeremy,

the routing part is simple

ip route 0.0.0.0 0.0.0.0 link1

ip route 0.0.0.0 0.0.0.0 link2 200

this makes link2 a backup in the real command link2 can be or a L3 interface name or the ip address of the next hop.

The NAT part can be more complex if the two links are with different providers but it can be managed using route-maps with NAT

if with a single provider the NAT part is simpler.

if you like you can provide more details to get better help

Hope to help

Giuseppe

Jembeck22 · ‎12-23-2008

Hi Giuseppe

My IS is with two different providers. so am i correct at say I will configure two static routes the first pointing to the ip address of the router of the primary ISP eg 192.168.2.45 255.255.255.0 link1 and the second pointing to the router of secondary ISP eg 192.168.2.68 255.255.255.0 link2 200

or would it point to the public ip address of the ISP's

Giuseppe Larosa · ‎12-24-2008

Hello Jeremy,

you can use the ip next-hop= ip address of ISP.

if you have two ISPs you get two public ip addresses blocks.

the following example looks like your scenario

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_configuration_example09186a0080950834.shtml

Hope to help

Giuseppe