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Community Member

Default Route through EIGRP at branch office

Trying to figure out how to handle routing internet traffic through branch office that has their own ISP however corporate office has default route set.

Current Setup

==================

ISP <--- SITE A (Corporate Office) ---[MLPPP Link]--- SITE B (Branch Office) ---> ISP

A has a default route 0.0.0.0/0

B has A's default route through EIGRP

==================

How can I have B route internet bound traffic through B's ISP and not through A's ISP?

Looking for any options. I would however like to have a failover back to A if B's ISP is down, or vise-versa.

A and B both have Cisco 3825's.

2 ACCEPTED SOLUTIONS

Accepted Solutions
Cisco Employee

Re: Default Route through EIGRP at branch office

At site B add a static route with ISP (B)

ip route 0.0.0.0 0.0.0.0

If the ISP access link is down, it will use the EIGRP route through site A.

Hall of Fame Super Blue

Re: Default Route through EIGRP at branch office

You can use distribute-lists within EIGRP to filter which routes, either outgoing or incoming on an interface, are allowed -

https://www.cisco.com/en/US/docs/ios/12_1/iproute/command/reference/1rdeigrp.html#wp1024147

Jon

8 REPLIES
Cisco Employee

Re: Default Route through EIGRP at branch office

At site B add a static route with ISP (B)

ip route 0.0.0.0 0.0.0.0

If the ISP access link is down, it will use the EIGRP route through site A.

Community Member

Re: Default Route through EIGRP at branch office

Thanks, I just found this out through here -> http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094195.shtml

I can manipulate through distance values.

Hall of Fame Super Blue

Re: Default Route through EIGRP at branch office

Ryan

Simplest solution would be to have a default route in site B also pointing to the ISP in site B.

Use an offset list and increase the metric of the default route from site A so that the default route in site B is preferred. If the default-route from Site B is lost then the one pointing to site A will be used. So you would apply the offset-list to the LAN facing interface on Site B WAN router that connects Site B to Site A -

http://www.cisco.com/en/US/docs/ios/iproute/configuration/guide/irp_cfg_eigrp_ps6350_TSD_Products_Configuration_Guide_Chapter.html#wp1054179

Jon

Hall of Fame Super Gold

Re: Default Route through EIGRP at branch office

Ryan

Some things about how to implement this would depend on details of your environment which we do do know. But in general you should be able to have siteB send its traffic to the Internet through its own Internet provider by configuring a local static default route. The local static default route would be preferred to the learned EIGRP default route. And if the local route is withdrawn from the routing table because the siteB provider is down, then the learned EIGRP default route would be used, which provides the fail over that you want.

HTH

Rick

Hall of Fame Super Blue

Re: Default Route through EIGRP at branch office

Rick

Agreed but that is assuming that Site B only has one router. Appreciate as you say we don't know the full topology but if Site B has more than one router and runs EIGRP internally then a local static default route would not work by itself.

Hence the reason i suggested an offset list. However if there is only one router in Site B then a local static route is the way to go.

Jon

Community Member

Re: Default Route through EIGRP at branch office

There is only one router there.

My next question would be what if there was a second branch office with and ISP. These static routes would be getting distributed via EIGRP so is there a way to not distribute a static route through EIGRP, as an exclusion perhaps?

With the specification of 'no redistribute static' in EIGRP this should work at the branch office router without distributing that route.

Hall of Fame Super Blue

Re: Default Route through EIGRP at branch office

You can use distribute-lists within EIGRP to filter which routes, either outgoing or incoming on an interface, are allowed -

https://www.cisco.com/en/US/docs/ios/12_1/iproute/command/reference/1rdeigrp.html#wp1024147

Jon

Community Member

Re: Default Route through EIGRP at branch office

You are exactly right and I had networks with this very situation and used this solution just fine. Typical of us network folk many others are over complicating the problem and over thinking the solution. Why oh why?

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