Use two TCP/IP addresses

Note that this documentation is current for Sendmail versions up to 8.12.9. For further inquiries about Sendmail beyond the scope of this documentation, please see http://www.sendmail.org/.

In this scenario, your machine uses two TCP/IP addresses, and has two machine names. Sendmail will run on one TCP/IP address, and receive mail there. ListManager will run on the other TCP/IP address and receive mail there. Each TCP/IP address should resolve to a different DNS host name, so that people can send email to either address by using the appropriate host name.

The advantage of this approach is that it is very straightforward to set up and does not cause any dependency between Sendmail and ListManager. Thus, it is also very reliable.

For example, if your machine is named "apollo.mycorp.com" and has the TCP/IP address "207.105.6.10", you might also assign your machine the TCP/IP address "207.105.6.11" which resolves to "juno.mycorp.com". Sendmail would be told to use the "apollo" address, and ListManager could use the "juno" address. To the outside world, it will appear that your network has two machines, "apollo" and "juno", when actually they are one machine, with two TCP/IP addresses.

The first step in implementing this method is to obtain, from your network administrator, a second TCP/IP address, and to make sure that a separate host name is assigned in the DNS for it.

After you have added a TCP/IP address

The next step is to configure Sendmail to use only one TCP/IP address. If you do not do this, Sendmail will automatically use all the TCP/IP addresses on your machine and none will be available for ListManager.

To restrict Sendmail to one TCP/IP address, add the following line to your /etc/mail/sendmail.cf file where the rest of the "O" options are specified:

O DaemonPortOptions=Port=26,Addr=207.105.6.11, Name=MTA
 

Older versions of Sendmail use this line:
 

OOAddr=207.105.6.11

Substitute your 1st TCP/IP address for 207.105.6.11. This Sendmail option is explained in the "Options" chapter of the O'Reilly Sendmail book. Note that there cannot be other lines with DaemonPortOptions.

You will now need to restart Sendmail. Be sure to telnet to port 25 on each TCP/IP address to ensure that Sendmail is using the correct TCP/IP address.

apollo# telnet 207.105.6.10 25
Trying 207.105.6.10...
Connected to 207.105.6.10.
Escape character is '^]'.
220 apollo.mycorp.com ESMTP Sendmail 8.8.5/8.8.5; Mon, 16 Jun 1997

apollo# telnet 207.105.6.11 25
Trying 207.105.6.11...
telnet: Unable to connect to remote host: Connection refused

You should now go ahead and install ListManager. Once ListManager is installed, you will need to tell ListManager to use the 2nd TCP/IP address in Utilities: Administration: Sites: Edit Site: SMTP.

The "127.0.0.1" is added so that you can connect to ListManager from your own machine. By default, the web interface uses 127.0.0.1 to connect to the ListManager.

You are now ready to use ListManager! You can start ListManager in the foreground with the command "lm start". The first time, we recommend that you run ListManager in the foreground, so that any error messages are immediately displayed. If you would like complete debugging information, add the "debug" parameter when you run ListManager, as in: "lm start debug"