In a nutshell, we have a webserver behind a BigIP and the user gets connected to real server by connecting to VIP. I can telnet to Vserve on port 80, However wget says "Read error (Connection reset by peer) in headers." I've checked the NAT config on Vserver, it's set to automap & a similar setup in parallel DC works completely fine.
This was working fine over a year, though have issues now for over a week !
Any help will be appreciated !
My advise would be to do some packet captures. Set up a tcpdump on the external interface of the BIG-IP, filtering on the VIP address, and another tcpdump on the internal interface of the BIG-IP, filtering on the web server's address. You want to see good traffic entering the VIP, going to the web server, and returning from the web server back through the VIP. If any one of those things isn't happening then you have a routing problem. If you do see return traffic from the web server, not just a reset, then I'd probably do a cURL directly form the BIG-IP and see how the web server responds.