Please consider this issue with what appears to be DNS issues. We have HQ, that had a single connection to site A, via a carrier's MPLS network. A contractor was previously hired to install a second router at site A, connected via ADSL to the public internet. An IPSec tunnel was set up between the ADSL router and the Cisco PIX at HQ. The plan was to use route-maps at each end, redirecting key traffic for the Exchange server and MS ISA server (both at HQ) to pass through the IPsec tunnel. However, due to a fault with original router at Site A, the route-map never redirected traffic. Instead, at Site A, DHCP was changed to make the ADSL router the default gateway for clients. At HQ, a route-map was applied at the core L3 switch to redirect the server traffic to the PIX.
All seemed to be working well, and a tracert confirmed that traffic is going over the correct routes. However, some clients also use wireless at Site A, and get an additional address when using it. I suspect that this is causing problems with the email client and IE (IE connecting to an ISA Server at HQ). Sometimes Outlook and IE both fail to connect to the servers at HQ, although ping tests and the Citrix client are not affected. DNS at HQ now shows 2 addresses for one of the clients.
It looks like a DNS issue with the replication of the zone back to HQ, but I am not sure why this would not also be an issue previous to the ADSL router install. Not all subnets from HQ are route-mapped down the IPSec tunnel, but the server subnet is.
What would you advise for the next step?
Thank you in advance!