When we route http or Https traffic over our backup T1 our squid proxy server stops being able to reach anything. This has worked in the past, however we recently replaced the T1.(mere hours ago)
Computers have firefox configured to use the proxy, it is not a transparent proxy. If we remove the proxy they can connect over the T1.
Network setup: Single Linksys Rv082 router with a primary WAN link to a cable line and a secondary link to a T1 connection. We also have a freebsd server (Server A) running DNS and a PC-BSD server (Server B) as our squid proxy server. Server A has the name servers from both WAN1 and WAN2 in it's resolve.conf file. Server B is now running bind only as a local name server for cacheing, it contacts Server A for name resolution.
We at first suspected DNS issues, however if computers do not use the proxy they can connect.