Here are some great tools :

http://multirbl.valli.org/

http://mxtoolbox.com/blacklists.aspx

troubleshooting commands :

How to troubleshoot spamming activities on postfix mail server.

1. To see the mail queue:

# mailq

2. To flush the mail queue:

# postfix flush OR

# postfix -f

3. To remove all mails from the queue:

# postsuper -d ALL

4. To remove all mails in the deferred queue:

# postsuper -d ALL deferred

5. To delete all queued messages from or to the domain called spamdomain.com:

# ./postfix-delete.pl spamdomain.com

6. To delete all queued messages that contain the word “abc” in the e-mail address:

# ./postfix-delete.pl abc

7. To know the number of messages sitting in the deferred queue:

# find /var/spool/postfix/deferred -type f | wc -l

8. To get a sorted list of the accounts that have the most mail in the queue. This usually means a maximum of 2 or 3 spammers at the end of the list:

# mailq|grep ^[A-F0-9]|cut -c 42-80|sort |uniq -c|sort -n|tailHere are some great tools :

http://multirbl.valli.org/

http://mxtoolbox.com/blacklists.aspx

and useful tutorials :

http://www.1a-centosserver.com/centos-linux-anti-spam-email-filtering/centos-postfix-spam-tips-and-quick-solution.php

troubleshooting commands :

How to troubleshoot spamming activities on postfix mail server.

1. To see the mail queue:

# mailq

2. To flush the mail queue:

# postfix flush OR

# postfix -f

3. To remove all mails from the queue:

# postsuper -d ALL

4. To remove all mails in the deferred queue:

# postsuper -d ALL deferred

5. To delete all queued messages from or to the domain called spamdomain.com:

# ./postfix-delete.pl spamdomain.com

6. To delete all queued messages that contain the word “abc” in the e-mail address:

# ./postfix-delete.pl abc

7. To know the number of messages sitting in the deferred queue:

# find /var/spool/postfix/deferred -type f | wc -l

8. To get a sorted list of the accounts that have the most mail in the queue. This usually means a maximum of 2 or 3 spammers at the end of the list:

# mailq|grep ^[A-F0-9]|cut -c 42-80|sort |uniq -c|sort -n|tail