> > > I also tried port 25 and 587 from a separate machine that has an IP > > address > > in mynetworks. In that case, EHLO is not even recognized: > > > > telnet <ipaddress> 587 > > 220 <myhostname> ESMTP Postfix (Ubuntu) > > EHLO client.example.com > > 502 5.5.2 Error: command not recognized > > HELO client.example.com > > 250 <myhostname> > > QUIT > > FWIW: that's sometimes a symptom of a broken firewall that thinks it > knows SMTP but does not, with the canonical example being a Cisco PIX in > its default configuration. > > That particular form doesn't look exactly like PIX-mangling, and I don't > think PIX (or its ASA spawn) interfere with port 587 by default, so it's > probably something else, but that something else may be something > claiming to be providing you network security while in the process > directly breaking the spec for port 587 mail submission. A port 587 > service that doesn't support EHLO is just antique SMTP on a weird port.
Thanks Bill, I discovered it was actually due to a setting in PuTTY . Under the Telnet settings, the default for "Telnet negotiation mode" is "Active". Setting it to "Passive" cleared the problem. Also, issuing a second EHLO also worked (which led me to check the telnet settings). Michael
