Wednesday, June 10, 2009
Backup MX records
I learned something today. Backup MX records can be a bad idea from a spam standpoint. Apparently, spammers have figured out that servers higher up on the MX priority chain do not have as much spam protection, but rather just generally collect everything and dump it to the primary server. So by sending spam directly to the backup servers, spammers can bypass blocklists and some other methods of filtering.