[Cialug] MTA HELO

[Nicolai]

On Sun, Jan 12, 2014 at 08:47:38AM -0600, Kevin Smith wrote:

> Thoughts? I'm not inclined to change given this is the only false in 15
> years; that I'm aware of. As long as I don't reject based on it not
> resolving, I believe I'm not violating the standard.

Heh, even most spammers know to send a FQDN.

You're not wrong, but if I were in your shoes I'd whitelist them.  This
isn't worth fighting over and I'd bet you your job that the other guy
is a better smooth talker than you are.  How else did he get the
job?

I think the following is relevant.

https://www.ietf.org/rfc/rfc5321.txt

2.3.5.  Domain Names

"A domain name that is not in FQDN form is no more than a
 local alias.  Local aliases MUST NOT appear in any SMTP
 transaction.  Only resolvable, fully-qualified domain names
 (FQDNs) are permitted when domain names are used in SMTP."

It goes on to list some exceptions to the rule that don't apply in your
case.  Just whitelist them and move on.  Keep the general requirement
though because like you say it's a cheap and effective tool for blocking
spam.

Nicolai