Greylisting. Was it ever a good idea?
Well, some say so. Greylisting (detailed at Greylisting.org) is a spam prevention technique for mail servers. The concept is simple:
– When your mail server receives a message from a new sender, the server temporarily rejects the message with a “try again later” or “delay” message.
– Most outgoing mail servers (senders) will indeed try again. Sometimes this doesn’t occur for a while, though. 15 minutes, 30 minutes, a hour….longer.
– When the message is sent again, it’s cleared and delivered to the user.
Most spammers don’t get this option. Spammers are smart, though! They know this trick. So, was this ever a good idea? Maybe. Is it useful now? I say no.
Disable Greylisting on Mac OS X Mountain Lion Server
Open Terminal on your server and execute the following command:
sudo serveradmin settings mail:postfix:greylist_disable = yes
You can restart the Mail server, as needed.
You’re done. Comment here if you have any challenges using this command.
Is Mac OS X Server 10.6 (Snow Leopard) rejecting your e-mail messages which lack a subject line? Mine was, and so does the default setting on Snow Leopard Server.
Here’s a quick fix:
1) First, stop the mail service.
2 Now, you’ll want to edit the header_checks file that’s utilized by postfix.
sudo nano /etc/postfix/custom_header_checks
3) Next, you’ll see a line which says:
/^subject: *$/ REJECT empty subject header
Comment out this line by adding a pound sign (#) at the beginning of the line.
4) Once you comment out this line, it should appear as:
#/^subject: *$/ REJECT empty subject header
5) If you’re using nano or pico to edit the file, click Control+O to write the file. (Save and Exit).
6) Now, restart the Mail service and the server will no longer reject email with no subject line.
Let me know if this solution works for you! Enjoy!