Manager Guide: "Content not explicitly allowed" / Garbled Messages

Our mailing lists are set by default to disallow attachments of any kind, as well as formatted text (or HTML). See "Don't Use Styles in Your Messages!" for more information about why we have this policy, and how subscribers can avoid sending messages that will be discarded or garbled, or result in error messages.

Although it's best for your list members to understand this policy so they can format their messages appropriately and avoid having their messages arrive to the list looking very different from what they've sent, there are a couple of list settings that will help avoid messages being completely discarded or unintelligible.

On http://lists.uua.org/mailman/admin/listname/contentfilter ("Content filtering"), be sure your settings match the following:

Description Value

Should Mailman filter the content of list traffic according to the settings below?

No Yes

Admin note regarding the above: it's very important to filter the content of your list traffic; this can be crucial in preventing viruses from being spread to your list members.

Remove message attachments that have a matching content type.

Remove message attachments that don't have a matching content type. Leave this field blank to skip this filter test.

multipart/mixed multipart/alternative text/plain text/html

Admin note regarding the above: most likely, the only change required here is to add the line of text that says, "text/html".

Remove message attachments that have a matching filename extension.

exe bat cmd com pif scr vbs cpl

Remove message attachments that don't have a matching filename extension. Leave this field blank to skip this filter test.

Should Mailman collapse multipart/alternative to its first part content?

No Yes

Should Mailman convert text/html parts to plain text? This conversion happens after MIME attachments have been stripped.

No Yes

Admin note regarding the above: it is the UUA's long-standing policy to disallow HTML messages to lists hosted on UUA.org.

Action to take when a message matches the content filtering rules.

Discard Reject Forward to List Owner Preserve

Admin note regarding the above: choosing "Reject" here will send an error message to the subscriber if they send an email that breaks the rules set on this page. This is important since it will tell them what to change in order to successfully re-send their message, or, if they need additional help, the error message will help the list manager and/or the OEC diagnose the problem.