jtwcc
@buckeyecom.net
| [Config] Default route & routing loop
How do I stop a routing loop between my border router and my ISP, when I use a default route pointing to my ISP, I run RIP on my internal routers, and one of my networks goes down? When the network goes down, it is eventually removed from the routing tables of all routers, but if someone tries to send packets to the missing network, it gets routed via the redistributed default route to the ISP. It then gets routed back to my border router via the ISP summary route pointing to my internal networks. |
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deepblackmag
join:2004-12-27
00000
2 edits | You should probablly have a static route pointing toward null0 for your summary on your border router.
When it loses the prefix for a specific network, it will drop the traffic rather than creating a routing loop.
Example:
i own 1.2.0.0/16 and have specific /24 networks behind it.
1.2.3.0/24, 1.2.4.0/24, 1.2.5.0/24.
On my border router, i would advertise 1.2.0.0/16 to my service provider via BGP. I would add a static route:
ip route 1.2.0.0 255.255.0.0 null0
Also to prepare for the future, i would implement BGP at the edge and move to a faster converging IGP (such as OSPF) for the interior of your network. |
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