I would like to give a few clues for this frequently asked question in the forums section of ÇözümPark.com.

If you have set up a mail server, but the mails you send are sent to the other party as spam or do not reach at all, and again this topic is for you. If you’re getting 550.5.7.1 errors in NDR messages about , you are probably on the RBL lists. Well, how do we verify this.

First of all, check if you have MX record for the mail domain. For this, by typing your domain name at the address below, there must be a minimum of 1 mx record in return.

http://mxtoolbox.com/

There will be a possible record and check the RBL for the corresponding ip address

http://www.anti-abuse. org/multi-rbl-check/

If you are listed in one or more RBLs, read the article below to delete

http://www.cozumpark.com/blogs/exchangeserver/archive /2008/03/28/spam-mail-ve-rbl-realtime-blackhole-list-aras-nda-li-ki.aspx

Well, there is no problem with RBL, in this case SPF for this domain check the record

http://wiht.link/sender-id

If you do not have an SPF record, then open an SPF record on your DNS server

http: //www.cozumpark.com/blogs/windows_server/archive/2008/05/12/dns-doma_3101_n-name-system.aspx

So there is SPF, not RBL It is necessary to check the vendor-based systems that detect high mail sending for your ip address

http://www.senderbase.org/index
http://www.mcafee.com/us /mcafee-labs/threat-intelligence.aspx