reject_unknown_helo_hostname and an address literal
If I use the 'smtpd_helo_restrictions' option parameter
'reject_unknown_helo_hostname', will a hostname that is an address
literal be rejected?
- On Mon, May 13, 2013 at 04:30:51PM +1000, Nikolas Kallis wrote:
> If I use the 'smtpd_helo_restrictions' option parameterFWIW, you don't have to use it in smtpd_helo_restrictions; other
restriction stages can have HELO-based restrictions also. See
SMTPD_ACCESS_README.html for the overview.
> will a hostname that is an address literal be rejected?No. (I think per RFC 5321, an address literal is not the same as a
hostname, by way of explanation. *_hostname restrictions are only
applied to hostnames.)
But I willfully reject address literal HELOs on port 25. A mail-
exchanging host should have a real hostname. By local policy
decision, I only consider an address literal HELO as valid if given
by a user's MUA on submission. I've never known of a loss of real
mail as a result of this policy.
Perhaps what you really need is to separate your submission stream
from your MX inbound stream. If you can't/won't force users off of
port 25, you could use a different IP.add.re.ss:25 as your MX, and
leave the old one to your users.
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