BGP query

[yashdedhiya]

Hello,

I hv two ISP connection. ISP1 peering has done on one router for 3 of my networks(x.x.x.x). ISP2 peering has done for one network (y.y.y.y) on another router.HSRP is running between these two routers. I am advertising all my 4 networks via both router (ISP 1 and ISP2)But the problem i'm facing is that i'm receiving advertisement via my 2nd ISP and not via ISP1.

I want to rx x.x.x.x n/w via ISP 1 and y.y.y.y via ISP2. But both n/w (i.e x.x.x.x and y.y.y.y) is rxed by ISP 2.

I hv done the prepending of ISP2 network block in ISP1 router and ISP1 network block in ISP2 router.

Please find the attached ISP 1 and ISP 2 router configuration.

[mohammedmahmoud]

Hi there,

Lets agree on a couple of facts, using perpending has nothing to do with receiving advertisements from you ISPs, its all about filtering (using destribute-list, prefix-list or route-map), accordingly i can't understand the use of "neighbor x.x.x.x distribute-list 40 in" ?

regards,

Mohammed Mahmoud.

[yashdedhiya]

Hi!!!,

Ya i know that.I want x.x.x.x n/w to be available via ISP 1 and same x.x.x.x n/w to rx via ISP 2 but as a backup path and y.y.y.y n/w to be be rx from ISP 2 as primary and y.y.y.y n/w to be rx from ISP 1 as backup.With Distribute list we can either filter the ip network block.

In my case i want to rxe all ip blocks and not to block and ip blocks.i.e i want x.x.x.x/24 to rx via ISP 1 as primary and x.x.x.x/24 to rx via ISP 2 as backup when primary fails.same way for y.y.y.y/24 ip network block.

Please do let me know ur reply.

Waiting for ur reply.

Regards,

Yash

[yashdedhiya]

Hi!!!,

Ya i know that.I want x.x.x.x n/w to be available via ISP 1 and same x.x.x.x n/w to rx via ISP 2 but as a backup path and y.y.y.y n/w to be be rx from ISP 2 as primary and y.y.y.y n/w to be rx from ISP 1 as backup.With Distribute list we can either filter the ip network block.

In my case i want to rxe all ip blocks and not to block and ip blocks.i.e i want x.x.x.x/24 to rx via ISP 1 as primary and x.x.x.x/24 to rx via ISP 2 as backup when primary fails.same way for y.y.y.y/24 ip network block.

Please do let me know ur reply.

Waiting for ur reply.

Regards,

Yash

[yashdedhiya]

Hi!!!,

Ya i know that.I want x.x.x.x n/w to be available via ISP 1 and same x.x.x.x n/w to rx via ISP 2 but as a backup path and y.y.y.y n/w to be be rx from ISP 2 as primary and y.y.y.y n/w to be rx from ISP 1 as backup.With Distribute list we can either filter the ip network block.

In my case i want to rxe all ip blocks and not to block and ip blocks.i.e i want x.x.x.x/24 to rx via ISP 1 as primary and x.x.x.x/24 to rx via ISP 2 as backup when primary fails.same way for y.y.y.y/24 ip network block.

Please do let me know ur reply.

Waiting for ur reply.

Regards,

Yash

[mohammedmahmoud]

Hi there,

Ok i got you now, your prepending configuration seems ok, look what you're gonna do now is contact your 2 providers to make sure that they receive your routes with the correct prepending as this can't be checked from your local routers.

regards,

Mohammed Mahmoud.

[yashdedhiya]

Ok fine thanks for ur suggestion

[ashishpanda]

Hi Yash,

Check with ISP1 whether they are doing route Aggregation/summarization and if the AS path information are being advertised intact by them to their upstream.

thanks and regards

Ashish