F5 LTM VE 10.2.3: ip forward virtualserver

Just run a tcpdump on the F5 to see which side is initiating the RST packet, though it is almost certainly going to be your DB server:

tcpdump -nni 0.0 host 172.16.176.33

Connection refused likely means either the DB server isn't listening on 1521, or isn't allowing connections from your F5. This behavior would be indicated by the F5 sending a SYN packet, and the DB server responding with an immediate RST. You can post the output of the tcpdump here if you want the community to take a look.

Thanks a lot for your quick answer, and sorry for my delay. Tomorrow, a network guy will have a look at the tcpdump. Anyway, is there an irule to assign to an ip forward virtualserver, so that I could see the client IP of each request that receives this ip forward virtualserver. Thx a lot.

Yes, this is a simple one:

rule TCP_logging {
 when CLIENT_ACCEPTED {
  set remote [IP::remote_addr]:[TCP::remote_port]
  set vip [IP::local_addr]:[TCP::local_port]
  log "Rule TCP_logging fired, from $remote to vip $vip"
 }
}

Thank you again

Hi again, I am going to accept your offer, and I would like to send you the tcpdump files, but I do not know how. Can you help me, please? Thanks, Almu