We have a BGP multihoming setup with same upstream provider and we are using 2 * routers for this setup at our end. We are recieving default routes from provider and advertising our prefixes to provider from both edge routers. Both edge routers are connected with firewalls and these firewalls are connected with 2* core switches. We had a problem yesterday after upgradation of OS of both firewalls that traffic from internet was reaching to servers from 1 internet link but on the other link it was dropping on router. This problem was nothing to do with firewall upgradation bcz traffic was reaching from other link. So I shuted down the bgp neighbor relationship with provider and then resume after a while. After this step traffic started coming from this router towards firewall as well. Kindly shed some light on this issue , what could be the possible issue ? it seems strange.