### Postfix "cannot connect to saslauthd server: Permission denied" ###
       
       
       When using SASL authentication, Postfix has to access /var/spool/postfix/var/run/saslauthd. However, in some cases, this specific directory has wrong permissions (in my case, saslauthd was owned by root:root, without any read permission for anyone besides the owner). This leads to such entries in mail logs:
       
         warning: SASL authentication failure: cannot connect to saslauthd server: Permission denied
       
       Of course, setting some less restrictive permissions solves the issue... But the solution is not persistent. After a reboot, the /var/spool/postfix/var/run/saslauthd directory gets its "old" permissions back. Why? I don't care. I just want this dang directory to be readable by Postfix after any reboot. :)
       In fact, the directory seems to be recreated at every reboot, which explains the "lost permissions memory" behavior. The solution I found was using dpkg-statoverride to make the permissions on that directory persistent:
       
         dpkg-statoverride --add postfix root 710 /var/spool/postfix/var/run/saslauthd
       
       Now, my SASL authentication works like a charm (even after a reboot)!