====== Debugging e-mail problems ======


===== Check if the server hostname is resolvable forward and reverse: =====

<code>
Prompt$> host your-servername.example.com
your-servername.example.com has address 192.0.2.100

Prompt$> host 192.0.2.100
100.2.0.192.in-addr.arpa. domain name pointer your-servername.example.com.
</code>

===== Check if mailserver is accepting connections and answers with correct HELO/EHLO =====
<code>
Prompt$> telnet your-servername.example.com 25
Trying 192.0.2.100...
Connected to your-servername.example.com.
Escape character is '^]'.
220 your-servername.example.com ESMTP MAIL Server
</code>\\
If the servername is not correct you can adjust it in /etc/postfix/main.cf altering the smtpd_banner parameter

===== Check that you have not configured a virtualdomain as mydestination in main.cf =====
<code>
Prompt$> postconf | grep "^my"
mydestination = $myhostname, $mydomain
mydomain = $myhostname
myhostname = your-servername.example.com
mynetworks = 127.0.0.0/8
mynetworks_style = subnet
myorigin = $myhostname
</code>\\
When you have configured mydestination containing example.com and have mail-accounts setup in ispcp for example.com this wont work.\\
 Postfix tells that in the logs by saying: "do not list domain in BOTH mydestination and virtual_alias_domains"

===== Check policy daemons =====
When you don't receive an e-mail and the logs show "451 Server configuration error" this is possibly because of an problem with connecting a policy daemon.\\
In this case a deeper look in the logs will point out:\\
"warning: connect to 127.0.0.1:12525: Connection refused" or "warning: connect to 127.0.0.1:60000: Connection refused"\\
This means postfix cannot connect to policyd-weight and/or postgrey.\\
Check if you have this services installed using your distros package managing solution (apt-get or yum or whatever)\\
Check if the services are listening on the correct port. This can be done by typing "netstat -an | grep 12525" into the command line.\\
\\
If you have no intention to use the policy daemons configured in the default ispcp environment, remove them from the config:\\
You find them in the "/etc/postfix/main.cf" in the directive "smtpd_recipient_restrictions".\\
Policy-weight is the option check_policy_service inet:127.0.0.1:12525.\\
Postgrey is the option check_policy_service inet:127.0.0.1:60000.\\

===== Check if dns is working =====
<code>
Prompt$> host www.google.com
</code>
should give you some ip addresses.\\ 
If postfix run in chrooted environment ensure that the resolv.conf in the chroot is identical to /etc/resolv.conf\\
You can check if postfix runs chrooted with the following command:\\
<code>
Prompt$> grep -v "^#" /etc/postfix/master.cf | grep "smtpd$" 
smtp      inet  n       -       y       -       -       smtpd
</code>
According to "man 5 master" the fifth column defines if service is chrooted or not. On most distros a "y" or a "-" in the fifth column means the service is chrooted. Centos, debian and maybe others chroot to "/var/spool/postfix", so the resolv.conf used by postfix would be stored as "/var/spool/postfix/etc/resolv.conf"

===== Further assistance =====
If the above checklist and your inquiry in the forums does not lead to the resolution of your problem, you can ask for help in the forum:\\
Such a request has to include at minimum the following informations:\\
  * IspCP Release (if trunk, svn co date or revision number)
  * Realserver / Vserver
  * Behind natted firewall / direct routed
  * Distribution / OS used
  * Output of postconf -n
  * Output of grep -v "^#" /etc/postfix/master.cf 
  * Complete log of an smtp session that leads to the problem (not the whole maillog / mail.info)
  * Mailclient / Webmailproduct you use\\

Detailed description of the problem!!!\\
We won't answer threads which say "I can't send mails, please help, its urgent"