BGP set local preference

Unanswered Question
Aug 8th, 2009

I have two routers in the same AS connected to the same upstream ISP. i'm trying to use router A and its link to the internet primarily and router B and its link only for backup.

my outbound plan is to have the BGP session for link A install a route to 0.0.0.0 and if this fails then a static route with a high metric to router B will be able to carry all my traffic.

my inbound plan is to advertise my class C via both BGP links however router B is setting the metric to 200 via a routemap.

On route A The ISP is only sending the origin route (0.0.0.0/0) but they are also withdrawing lots of routes as the topology of the internet changes. I'm not sure if this is interfering with my 0.0.0.0/0 but i just don't see where it is withdraw in the debugs yet sh ip bgp stats say 1 route received and 1 withdrawn.

I have tried a number of configurations but each of them usually end up with either a) the incoming route is blocked by my own route map or b) the route is received then withdrawn.

how do i get their origin route to stick in my route tables?

Thanks in advance,

Leon

I have this problem too.
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u1kumar2002 Sat, 08/08/2009 - 11:45

Plz go thru below config ..............

It will help you to filter the route from ISP ..........Using prefix-list

router bgp XXXX

no synchronization

bgp log-neighbor-changes

network X.X.X.X mask 255.255.252.0 { Local Network }

network X.X.X.X mask 255.255.255.0

network X.X.X.X mask 255.255.255.0

neighbor X.X.X.X remote-as 6666

neighbor X.X.X.X timers 30 90

neighbor X.X.X.X default-originate { 1st ISP }

neighbor X.X.X.X weight 150 { 2 nd Preffered Path }

neighbor X.X.X.X prefix-list AAA in { Incoming Traffic }

neighbor X.X.X.X remote-as 6666

neighbor X.X.X.X timers 30 90

neighbor X.X.X.X default-originate { 2st ISP }

neighbor X.X.X.X weight 200 { 1 st Preffered Path }

neighbor X.X.X.X prefix-list AAA in { Incoming Traffic }

no auto-summary

ip prefix-list AAA seq 10 permit 0.0.0.0/0 { Allow only Default Route From ISP }

u1kumar2002 Sat, 08/08/2009 - 11:48

Plz go thru below config ..............

It will help you to filter the route from ISP ..........Using prefix-list

router bgp XXXX

no synchronization

bgp log-neighbor-changes

network X.X.X.X mask 255.255.252.0 { Local Network }

network X.X.X.X mask 255.255.255.0

network X.X.X.X mask 255.255.255.0

neighbor X.X.X.X remote-as 6666

neighbor X.X.X.X timers 30 90 { 1st ISP }

neighbor X.X.X.X weight 150 { 2 nd Preffered Path }

neighbor X.X.X.X prefix-list AAA in { Incoming Traffic }

neighbor X.X.X.X remote-as 6666

neighbor X.X.X.X timers 30 90 { 2st ISP }

neighbor X.X.X.X weight 200 { 1 st Preffered Path }

neighbor X.X.X.X prefix-list AAA in { Incoming Traffic }

no auto-summary

ip prefix-list AAA seq 10 permit 0.0.0.0/0 { Allow only Default Route From ISP }

ldmccalla Sat, 08/08/2009 - 12:59

thanks a lot. this is really getting close but i have a little problem..

Aug 8 16:45:32.988: BGP(0): x.x.x.25 rcvd 0.0.0.0/0

Aug 8 16:45:32.992: BGP(0): Revise route installing 1 of 1 routes for 0.0.0.0/0 -> x.x.x.26(main) to main IP table

Aug 8 16:45:32.992: BGP(0): route 0.0.0.0/0 down

chinkevi_2 Tue, 08/11/2009 - 17:38

please post your current config.

i gathered that

- you have 2 routers to the same isp running bgp.

- link A is primary for in and out traffic,

- link B is backup

- isp only advertise default route to you.

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