How to prevent the server getting blacklisted and to get removed from a blacklist database.
Spam is a huge problem on the Internet and as a mail server operator it is important to take reasonable steps to ensure that the server is secured from being hijacked by those wishing to distribute bulk unsolicited e-mail.
If the server is not configured correctly, spammers can use the mail
server to dispatch messages through the server uninhibited. Mail servers
accept messages for recipients that have their mailboxes hosted on the mail
server itself, but it is critical to regulate who can send messages to others
(non-local recipients). Secure the server by configuring strict rules as to
who can use the server to send messages (relay messages) to non-local
The article What are the best relay settings to use? describes which relay settings are most appropriate.
Review any domain redirections mail users may have set up on the server. If mail users have been permitted to redirect their mail to other mail systems then they will also be redirecting any spam to those mail systems. These mail systems will detect the server as spamming and this may cause the server to be blacklisted as a result. As such, in a hosted environment, either moderate the use of redirections, or prevent users from redirecting their mailboxes by disabling the feature in web mail.
It is possible to get blacklisted or have your server IP(s) blacklisted via notifications being incorrectly sent to a forged senders address. Here are the common ways that notifications or bounced messages where replies to a forged address from a message envelope can have you added to a blacklist;
Another way that your server could be blacklisted is through blacklisting of a range by a DNSBL. Here is a returned warning from the web site of a DNSBL after a server range has been blacklisted;
WARNING!!!! This entire Class C, /24 network is listed!!!
2 or more /32 server entries in any /24 network will get the entire /24 network listed on ricn.dnsbl.net.au and rmst.dnsbl.net.au
If the server is not secured from unauthorized relay, it will end up on an Open Relay Blacklist. Once the server is on a black list, the removal process is very time consuming. The removal process is as follows:
1. First ensure that your server is not configured as open relay. Make sure
that the server is configured as suggested in the article What are the best relay settings to use?
2. Make sure your server is not being abused by reviewing http://www.mailenable.com/kb/content/article.asp?ID=ME020339
3. Next, determine which open relay black lists the server is listed on using the tools at www.mxtoolbox.com.
4. Finally, go to the web sites of each Blacklist provider and use their web site to submit your site for removal, if possible.
5. Blacklist providers may take time to process your removal.
How to configure DNS blacklisting: http://www.mailenable.com/kb/content/article.asp?ID=ME020162Blacklisting mechanisms:: http://www.mailenable.com/kb/content/article.asp?ID=ME020084
|Product:||MailEnable (All Versions)|
|Class:||HOWTO: Product Instructions|
|Created:||1/07/2003 6:04:00 PM|
|Revised:||Friday, April 28, 2017|