Date: Thursday, January 05, 2023 14:50:58 -0700
From: Sbob <sbob(a)quadratum-braccas.com>
Update:
If I run the test command as root, the command completes but the
mail has not arrived in my inbox, it has been 10min
# echo "test" | sendmail -s "test subject" my_user(a)my_domain.com
#
Look in the sending machine's logs. The name you appear to have
defined isn't a FQDN so it may be that the target machine is
rejecting it. There may be other issues, but first you have to see
that it's off your sending server.
You have to start sendmail as root (it drops privileges as necessary)
because of the permissions on various directories that it uses and it
wants to open the privileged port (25) to listen for incoming
connections.
Is there some reason you're trying to use sendmail? Postfix has been
the supported MTA for at least a few years.