Forum Discussion
Steve_Carroll_1
Nimbostratus
NimbostratusWhy is my F5 dropping telnet on port 25 for one network?
I have configured SMTP on my LTM (11.4.1) and have configured a SNAT of 10.229.104.37 so all connections from the LTM are sent with this address and I have no iRule configured.
If telnet 10.229....
Steve_Carroll_1Nimbostratus
NimbostratusI have resolved the issue and it seems that the previous F5 engineer put a packet filter on the LTM for port 25 and some networks.
However, the network in question was not in the allowed list. There was also a deny list for port 25. Also logging was disabled on both filters.
I've added the network to the allow packet filter and it now connect.
PT2012_73791Nimbostratus
NimbostratusHmmm. Glad you posted the answer. Same problem on a new SMTP VIP. Funnily I imagine it was on the same chassis. I can't see why logging on a filter would ever want to be disabled. It makes trouble shooting very hard.
