TZ170: telnet closes fast from the outside

[petenutz]

Apologies if this has been covered. The search functions seem to be broken right now. I can send mail with telnet internally, but from the outside I get "connection closed by foreign host". I see my traffic with the 'packet trace' diagnostic utility. But i don't see any errors or security logs pertaining to it. Can someone point me in the right direction to troubleshoot?

Thanks,
Peter