Forum Discussion
nitass
Apr 17, 2015Employee
I suspect due to backend server respond with http 400 bad request(for example ,F5 send ssl client hello to backend server which only accept plain http),then lb failed,then fallback host in http profile trigged
does server send reset or close a connection (fin)?
When a Fallback Host is defined, and the connection attempt to the selected load balancing target has failed by the time the BIG-IP LTM system is ready to send the request, the BIG-IP LTM system sends the specified HTTP redirect in the following situations:
A pool member has not been chosen (the system failed to select a pool or a pool member, or no pool members were available)
A pool member is unreachable (when no route to the target exists)
A pool member is unresponsive (resets a connection request)
A pool member closes an established connection before the request is sent
sol6510: BIG-IP system fallback host behavior when a host is down
https://support.f5.com/kb/en-us/solutions/public/6000/500/sol6510.html- Robert_47833Apr 17, 2015Altostratushi ,Nitass what I found is : if F5 send ssl client hello to backend server which only accept plain http, then backend server responds with http 400 bad request , then F5 said handshake failure, then fallback host defined in http profile is sent back to client within http response header :302 location http://fallback-host.xx.com