When adding to the list, Server Admin accepts a variety of notations. You can:
ÂÂ Enter a single IP address or the network/netmask pattern, such as 192.168.40.0/21.
ÂÂ Enter a host name, such as mail.example.com.
ÂÂ Enter an Internet domain name, such as example.com.
Rejecting Mail from Blacklisted Senders
Mail service can reject mail from SMTP servers that are blacklisted as open relays by a
Blocking unsolicited mail from blacklisted senders might not be completely accurate. Sometimes it prevents valid mail from being received.
To reject mail from blacklisted senders:
1In Server Admin, select Mail in the Computers & Services pane.
2Click Settings.
3Select the Relay tab.
4Click the “Use these junk mail rejection servers” checkbox.
5Edit the list of servers by adding the DNS name of an RBL server:
ÂÂ Click the Add (+) button to add a server to the list, then enter the domain name of a
RBL server, such as rbl.example.com.
ÂÂ Click the Remove
Filtering SMTP Connections
You can use Mac OS X Server Firewall service to allow or deny access to your SMTP Mail service from specific IP addresses. Filtering disallows communication between an originating host and your mail server. Mail service doesn’t receive the incoming connection and no SMTP error is generated or sent back to the client.
To filter SMTP connections:
1In Server Admin, select Firewall in the Computers & Services pane.
2Create a firewall IP filter using the instructions in Network Services Administration, using the following settings:
ÂÂ Access: denied
ÂÂ Port number: 25 (or your incoming SMTP port, if you use a nonstandard port)
ÂÂ Protocol: TCP
ÂÂ Source: the IP address or address range you want to block
ÂÂ Destination: your mail server’s IP address
Chapter 2 Mail Service Setup
33
