Apple Mac OS X Server (version 10.2.3 or later) - Manual (Page 423)

Mail Service 423
Rejecting SMTP Connections From Specific Servers
Your mail service can reject non-authenticated SMTP connections from servers on a
disapproved-servers list that you create. Only someone who has an account with a CRAM-
MD5 or Kerberos password on your server can send your users mail or relay mail through
your server from a disapproved server.
To reject non-authenticated SMTP connections from specific servers:
1 In Server Settings, click the Internet tab.
2 Click Mail Service and choose Configure Mail Service.
3 Click the Filter tab.
4 Select “Reject messages from SMTP servers in list” and then edit the list of servers.
Click Add to add a server to the list.
Click Remove to delete the currently selected server from the list.
When adding to the list, you can use a variety of notations.
Enter a single IP address, such as 192.168.123.55.
Enter an IP address range, such as 192.168.40-43.*.
Enter an IP address/netmask, such as 192.168.40.0/255.255.248.0.
Enter a host name, such as mail.example.com
Enter an Internet domain name, such as example.com
5 Click Save.
Checking for Mismatched SMTP Server Name and IP Address
Your mail service can log and optionally reject connections from a server whose DNS name
doesn’t match the name that your DNS service gets when it looks up the server’s IP address.
This method intercepts junk mail from senders who pretend to be someone else, but may
also block mail sent from a misconfigured SMTP server.
Note: Reverse-lookups of IP addresses may slow the performance of your mail service
because lookups involve more contact with DNS service.
To check SMTP server names and IP addresses:
1 In Server Settings, click the Internet tab.
2 Click Mail Service and choose Configure Mail Service.
3 Click the Filter tab.
4 Select “Log connection if SMTP name does not match IP address” and then optionally select
“Reject if name does not match address.”
LL0395.Book Page 423 Wednesday, November 20, 2002 11:44 AM