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Dual Internet on 1841 and static routing

I've got an 1841 with two separate Internet connections via separate ISP's, one using fe0/1 and the other using ser0/0/0. fe0/1 currently provides all Internet including two L2L VPN's and all general Internet via NAT overload using fe0/1 IP. With second Internet T1 on ser0/0/0 I want to accomplish two things - dedicate all traffic from all inside hosts destined to a specific public IP out this line, and provide failover for this traffic back to the Internet on fe0/1 if this line drops. I'm not looking to provide two way failover from either line back to the other, only one way from ser0/0/0 back to fe0/1. Right now I've got separate public IP's on each interface with NAT overload ACL's on each. I've got fe0/1 set as the gateway of last resort, and static routes built to route traffic destined for the two specific public hosts over to ser0/0/0. Based on my limited testing so far, it looks like I also have to mirror permit/deny on the two NAT oveload ACL's for each interface:

ip nat inside source list 105 interface FastEthernet0/1 overload

ip nat inside source list 106 interface Serial0/0/0 overload

access-list 105 deny ip host <static host public IP>

access-list 105 permit ip any

access-list 106 permit ip host <static host public IP>

access-list 106 deny ip any

If that's the case then the failover won't work. What am I missing?

Thanks, Matt


Re: Dual Internet on 1841 and static routing

It will most likely be easier to use route-maps on your nat overload statements to do the selection. You can match the interface rather than IP's This allows you to control the nat selection via routing rather than ip addresses.

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