Email list administration

Notes on email lists

Email lists are created and administered through web site’s “control panel” at /cp. You will be prompted for the account’s userid and password. After that, click on “mailing lists” icon.

Our web site uses an email list server called ezmlm which stands for, I’m guessing, “Easy Mailing List Manager.” The user manual is at, and a faq is at Some definitions are helpful when reading this documentation:

  • The phrase “remote administration” refers to the ability to send commands to the server via email messages, without having to log into the control panel.
  • The words “administrator” and “moderator” are used interchangeably on our server, which is confusing, since the documentation makes a distinction between these roles.
  • The phrase “command line” in the documentation means the control panel web page with our server. You will see that there are many commands in the documentation that can be issued at the command line. We don’t have a real command line, so many of these commands are not available to us, and we have to do the best we can via either the control panel (web page) or remote administration (email).
  • The documentation talks about administrators sending commands to the server, and the server checking that the address in the From line is in the list of remote administrators (aka the list of moderators) before acting on the command. Our server, however, uses the email address in the Return-Path line since most email programs make it possible for anyone to put any email address in the From line, which enables abuse. Gmail is a good example of this. If you have an account, you can configure Gmail to put in the From line of your email. If you do this, the From line will contain and the Return-Path line will contain In this case, our server is going to check that is listed as a moderator, and not This is something to be aware of, but it isn’t a big problem, since you can list both and as moderators and never worry about this again.

When you create a new email list, don’t forget to configure it. This means clicking on the “config” link, defining the list owner address (probably your address), and checking a few configuration settings. I recommend the following settings:

  • Prefix subject with list name: This is optional. It causes the subject line of messages to look like “[name] subject” where “name” is the name of the list and “subject” is the author’s original subject line.
  • Remote administrators can list subscribers: This allows moderators to request a list of the addresses on the email list. Send an empty email message to the address “” where “name” is the name of the email list.
  • Remote adminstrators can edit texts: This allows moderators to edit the “Welcome” and “Goodbye” messages sent to people when the join and leave the list. Send an empty email message to “” for instructions and a list of the files that can be edited. There are about two dozen of them.
  • List is public: This means anyone can join the list (see below about confirmation), and must be set for remote administration to work on our server.
  • Remote administration: This enables remote administration of the email list using commands sent to the server via email.

There are two other settings that are important to know about:

  • Subscription without confirmation
  • Unsubscription without confirmation

If you always use the control panel to add and remove addresses, then just leave these two settings unchecked. If you use remote administration, however, and these settings are unchecked, then each time you add or remove an address from the list, a confirmation will be sent to that address via email, and the user will have to respond to that email to be added or removed. If you check these settings, then the address is added or removed immediately without confirmation. This is a slight security hole. Checking these settings has the effect of allowing anyone to add or remove any address to the list. So it is probably best to leave these settings unchecked, but if you are initializing a list, it might be convenient to check these settings temporarily until the list is initialized, and the uncheck them.

When you add or remove an address, a “Welcome” or “Goodbye” message will be sent to that address. Do not confuse these messages with the confirmation messages we just finished discussing. You can turn off the confirmation messages if you want to, but the “Welcome” and “Goodbye” messages will always be sent.

There is one more setting to discuss:

  • Only subscribers can post to list

This probably makes sense for any church-wide list, to cut down on the chance of spam, but don’t set it for any of the committee lists since we want everyone in the church to be able to send messages to the committees. If you do check this setting, the distinction between the From line and Return-Path line discussed above comes into play again, and the server is going to want to see the address in the Return-Path line listed on the “Subscribers” list or on the “Allowed” list. If someone complains that their address is subscribed a list but they can’t post to the list, look for the Return-Path line in the message they sent to you, and add this to the “Allowed” list.

Implementation notes

What follows are some obscure notes on implementing the web-based interaction with the server. The issue is whether the mail command should try to set the Return-Path line in the message to the server via the -r flag to sendmail. The answer is it depends.

It seems to be necessary in order for the -list command to work. As discussed above, the server checks that the address listed in Return-Path is in the list of moderators.

It seems to be unnessary for the -subscribe and -unsubscribe commands. But wait, it gets even stranger. If you configure “subscription without confirmation” and omit the -r flag to sendmail, the address is added immediately and a “Welcome” message is sent to the address. If you configure “subscription without confirmation” and use the -r flag, for some reason a confirmation message is sent to the address given by the -r flag before the address is added. On the other hand, if you configure “subscription with confirmation,” then a confirmation message is sent to the address regardless of whether you used the -r flag.

So I’ve chosen to use -r for -list, and omit -r for -subscribe and -unsubscribe.