Thursday, February 11, 2010

Sending mail issues because of spam blacklists

Problem
You may observe that your email is frequently marked as spam or even refused by mail servers. The first thing to do is to examine the log file of your mail host. You may see some errors by your smart host like:
Feb 11 2:10 PM mail mail.info postfix/smtp[48923]: 4A87C900BA: to <...>,
relay=smtp.smarthost.fld[123.132.122.133]:25, delay=802, delays=802/0/0.17/0.12,
dns=4.0.0, status=deferred (host smtp.smarthost.fld[123.132.122.133] said: 451 http://www.barracudanetworks.com/

What does this mean?
Well the recipient or your smarthost server refused the email because you are black listed at barracudanetworks.com (actually http://www.barracudacentral.org/reputation).

What to do?
Fist check where your public IP address or domain is black listed. Visit http://www.blacklistalert.com/ and provide your public IP address or domain and click check.
If you are black listed you may have several options:
  • Go to each black list organization and see if there is an option to remove your IP address or domain from the black list. Some black lists, like http://www.uceprotect.net/en don't allow removal at all.
  • Check the reason why you are black listed. It may be that not your IP address is black listed but the whole sub net of your provider. In this case you may consider contacting your ISP for resolving this.
  • You may try to send your email using your internet providers SMTP smarthost.
  • If it is your IP address, that is black listed examine how this could happen. Maybe someone made abuse of your Internet connection for sending spam. This may be done by some virus infected computer. Take measures to resolve this.
  • If you are using a dynamic IP address someone who used this address before may have sent spam or may have an infected computer used to sent spam. Ask your ISP for a fixed static IP address.
Further reading

No comments:

Post a Comment