by 
mailq Watch the mail queue
postfix -f Flush the mail queue
postsuper -d ALL To remove all mails from the queue
postsuper -d deferred deferred To remove all mails in the deferred queue
find /var/spool/postfix/deferred -type f | wc -l To know the number of messages sitting in the deferred queue
postcat -vq ID To view message content in queue with ID
qshape active Display number of emails being sent to each domain and how long they have been in the active queue
qshape deferred Display differed queue
tail -f /var/log/mail.log View the log in realtime
To check mail log for sent messages
cat /var/log/mail.log |grep -v "relay=local" |grep "relay=" |grep "status=sent"
To get statistics, install a script:
wget http://jimsun.linxnet.com/downloads/pflogsumm-1.1.1.tar.gz
tar -zxf pflogsumm-1.1.1.tar.gz
chown root:root pflogsumm-1.1.1
cd pflogsumm-1.1.1
cat /var/log/mail.log | ./pflogsumm.pl
You can move pflogsumm.pl to /usr/local/bin
To send a weekly report
Create /etc/cron.weekly/mailreport
#!/bin/sh
#
# mailreport cron weekly
MailSubject="Email report $(date +%d-%m-%Y)"
cat /var/log/mail.log | /usr/local/bin/pflogsumm.pl | /usr/bin/mailx -s "$MailSubject" your.mail@domain.com
exit 0
Change file permissions to read, execute
chown root:root /etc/cron.weekly/mailreport
chmod 755 /etc/cron.weekly/mailreport
Report today problems
pflogsumm -d today /var/log/mail.log --problems_first
Get permanent errors hard bounces
grep " dsn=5." /var/log/mail.log | grep -o -P " to=<(.+?)>" | sort | uniq -c
Get soft bounces
They start with 4…
grep " dsn=4." /var/log/mail.log | grep -o -P " to=<(.+?)>" | sort | uniq -c
To check user logins
grep "sasl_method=LOGIN" /var/log/mail.log
