DNS resolution failure after BGP failover to the backup link.

[wingsonhorizon]

Hi there,

I split my internal networks into two and balance them out to two WAN providers using EBGP and run IBGP on top of Metro connection between two 2821 routers at two different sites(15 miles apart).

I was able to failover with no problem, no ping drop at all. traceroute is fine too. however, when I tried to access to internet or my internal website, it can't resolve and goes no where.

Is there something that I missed like firewall blocking my traffic or DNS somewhere preventing this?

Thank you so much for your help in advance!!!

Ben

[johnd2310]

Hi,

Where is the DNS server sitting?

Thanks

John

[wingsonhorizon]

hi John,

I'm so sorry for reply so late. I tried to simulate the network in my lab to get rid of RIP failure problem.

and I was able to do that. However, this morning, I implemented the change, the user at the remote site still can't browse internal website or internet after the failover even though there isn't anymore RIB failure as of right now. I was able to ping and traceroute internal back to data center and 8.8.8.8

the same DNS server, no ACL blocking http or https traffic along the path.

thank you,

ben

[burtmianus]

Hiya,

Did you ever get this resolved? I'm experiencing basically the same issue - we have BGP failover for our ISP between two physical sites using a L2 link in between when failover occurs. Pings etc. are all fine but when it fails over DNS resolution doesn't work.

Would appreciate any help you can offer if you got it resolved.

Thanks

Chris