Hitchhiker's Guide to Openbsd

remotely sending mail through my OpenBSD system?
Try this: 
# grep relay-domains /etc/mail/sendmail.cf
The output may look something like this: 
FR-o /etc/mail/relay-domains
If this file doesn't exist, create it. You will need to enter the hosts who are sending mail remotely with the 
following syntax: 
.domain.com #Allow relaying for/to any host in domain.com
sub.domain.com #Allow relaying for/to sub.domain.com and any 
host in that domain
10.2 #Allow relaying from all hosts in the IP net 
10.2.*.*
Don't forget send a 'HangUP' signal to sendmail (a signal which causes most daemons to re-read their 
configuration file): 
# kill -HUP `head -1 /var/run/sendmail.pid`
Further Reading
●
http://www.sendmail.org/~ca/email/relayingdenied.html
●
http://www.sendmail.org/tips/relaying.php
●
http://www.sendmail.org/antispam/
10.5 - I've set up POP, but users have trouble accessing mail 
through POP. What can I do?
http://www.openbsd.org/faq/faq10.html (5 of 32)9/4/2011 10:02:15 AM

---

10 - System Management
Most issues dealing with POP are problems with temporary files and lock files. If your pop server sends an 
error message such as: 
-ERR Couldn't open temporary file, do you own it?
Try setting up your permissions as such: 
permission in /var
drwxrwxr-x 2 bin mail 512 May 26 20:08 mail
permissions in /var/mail
-rw------- 1 username username 0 May 26 20:08 
username
Another thing to check is that the user actually owns their own /var/mail file. Of course this should be the 
case (as in, /var/mail/joe should be owned by joe) but if it isn't set correctly it could be the problem! 
Of course, making /var/mail writable by group mail opens up some vague and obscure security problems. 
It is likely that you will never have problems with it. But it could (especially if you are a high profile site, 
ISP, ...)! There are several POP servers you can install right away from the ports collection. If possible, 
use 
popa3d
which is available in the OpenBSD base install. Or, you could just have the wrong options 
selected for your pop daemon (like dot locking). Or, you may just need to change the directory that it locks 
in (although then the locking would only be valuable for the POP daemon.) 
Note: OpenBSD does not have a group name of "mail". You need to create this in your /etc/group file if 
you need it. An entry like: 
mail:*:6:
would be sufficient.