Re: Question: should submit.mc include nocanonify by default?

Marco Moock <mm@dorfdsl.de> wrote:

On 12.05.2025 18:10 Uhr Stacey Marshall wrote:
>

Question, should submit.mc include nocanonify by default?
 
I was a little surprised to see SMTP client queue (sendmail -Ac)
trying to look up DNS names as I thought it only collected mail for
local accounts.  In the configuration in question the Mail Transfer
Agent (sendmail -bl) is configured to forward all mail to a gateway
machine for actual delivery, and only that gateway machine has access
to DNS.

>
Most machines that handle mail have access to DNS nowadays. If your's
doesn't, disable such lookups.
>

Thus I was wondering if submit.mc should include the nocanonify
feature by default?

>
I do not see a reason for that as most machines have access to DNS. A
default setting is something that fits general situations and not
corner cases.
>
Most servers also check the recipient domains and reject stuff that
isn't an FQDN or unresolvable, so the default checks are sane.

As I understand submit.mc is supposed to be "one size fits *ALL* ".
IMHO Your argument makes very good sense only if submit.mc is supposed
to be modified not only in super rare cases.

--
[Andrew] Andrzej A. Filip