postfix logs questions
 

ok, so I have setup a postfix mailserver and it seems to be working ok, we are only using this to relay mail to our forum users. Its not being used to recieve any email only send them out to the internet.

What is the difference between the mail.log and mail.info files? Can I turn one or both off? I see alot of messages like...

Jul 27 15:52:20 mail3 postfix/smtpd[12288]: CD8A84009FC: clientForumMailer.mydomain.com[192.168.5.51]
Jul 27 15:52:20 mail3 postfix/cleanup[12289]: CD8A84009FC: message-id=<>
Jul 27 15:52:20 mail3 postfix/smtp[12294]: connect to mx0.externaldomain.net[XXX.XXX.XXX.XXX]:25: Connection refused
Jul 27 15:52:20 mail3 postfix/smtp[12294]: connect to mx1.externaldomain.net[XXX.XXX.XXX.XXX]:25: Connection refused
Jul 27 15:52:20 mail3 postfix/qmgr[12168]: CD8A84009FC: from=<noreply@maillist.mydomain.com>, size=4481, nrcpt=1 (queue active)

Just wondering what this string of log entries means? Also I am getting duplicates in the syslog file as well.

grep mail /etc/syslog.conf

will tell you the difference between what is logged to those files

man syslog.conf

for more information

The postfix logs can be a little cryptic until you get used to them, but they supply a lot of information. Postfix runs as a set of different processes (daemons). In the log entries the smtpd, cleanup, and qmgr are some of them. What you are seeing is the flow of a message through the pipes and process of postfix. The numbers like "CD8A84009FC" are the IDs assigned to the message and you can trace a message through the queue looking at its id.

In the example you provide, message with id CD8A84009FC was received from you clientForumMailer at IP 192.168.5.51. It went to the cleanup process and then an attempt was made to forward this message to the next hop in the system: mx0.externaldomain.net, but the connection was refused (nothing listening at that address or it was fire walled). The message was placed back in the queue where is was likely deferred for a later attempt.