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New Member

Redundant Internet Access


We have the following configuration

Site A (subnet 2)

Cisco 4006 switch configured with default static route and connected to the firewall and then the Internet. It also has the ospf and rip routing enabled.

Site B (subnet 1)

Cisco 6509 switch configured with ospf and rip and getting the default route from O*E2 entry.

Site A and B are connected through wireless bridge.

We would like to have another internet connection at Site B, however we would like to have the internet connection through site A be a failover or redundant connection so that if anything is wrong with the connection at the Site B, Internet Traffic should be routed to Site A. What do I need to change on my switches to make this possible.

Also how to go about out Webserver and Exchange server, they will be NATed to a public IP address at Site B, how do make sure that they can be accesses also through Site A where it has a different firewall and different public IP address.

Any feed back will be appreciated.


Re: Redundant Internet Access

For network reliability and load balancing, this network includes two routers and two Catalyst 3550 multilayer switches, all with HSRP enabled. This ensures connectivity to the Internet, WAN, and mission-critical network resources if one of the routers fails.

New Member

Re: Redundant Internet Access

you have numerous issues, i can address some, first of all pick a routing protocol, rip or ospf. Also if site a and site b are connectected via a wireless "bridge" how are they on different subnets. Next is site b internet going to be used for site b and site a for site a, then they can fail over either direction? Are they the same isp's? Do your fw's also communicate via ospf (some can, not most) if not, how will your routers know if there is an isp issue. i.e. isp a goes down, it is connected to fw a, 4006 still has default route pointing at fw and will continue to forward traffic unless firewall can give some sort of notification that interface is down. The last issue with the public ip's for exchange server can be handled via dns, but you would need to get advice from someone other than me. But basically different public ip's would be put in dns and if one wasnt reachable the next would be given out.

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