Did anyone encounter such issue using https health monitor where suddenly it communicates with real server using TLSv1 instead of TLSv2?
I have a pair of F5 active-standby. All the while I was using https health monitor and F5 sent query using TLSv1.2. In fact the standby unit is still communicating using TLSv1.2. However the active unit suddenly use TLSv1 which causes the pool member to become inactive.
HTTPS monitors mark a TLS v1.2-configured pool member down and never mark it back up again, even if the pool member is up. The monitor works normally until the SSL handshake fails for any reason. After the handshake fails, the monitor falls back to TLS v1.1, which the pool members reject, and the node remains marked down.
Impact
Once the handshake fails, the monitor remains in fallback mode and sends TLS v1.0 or TLS v1.1 requests to the pool member. The pool member remains marked down.
Conditions
This might occur when the following conditions are met:
-- Using HTTPS monitors.
-- Pool members are configured to use TLS v1.2 only.
Workaround
To restore the state of the member, remove it and add it back to the pool.
the health monitor was working fine for the last several months. It communicate to server via tls1.2 and something happen we dont know what causes the sslhandshake to break and then F5 fallback to tlsv1...and since server dont support it becomes inactive on F5 end. F5 got stuck on tls1v.
