[Mailman-Users] Duplicate Subscription Confirmations

Mark Sapiro mark at msapiro.net
Thu Dec 11 21:52:41 CET 2008

Jim wrote:
>I have confirmed that one user who received the duplicate confirmation did, indeed, have a "subscribe" in the subject and the body. 
>Is there a way to protect against that behavior by the -request process? I would expect that process to detect that the requests were within the same email message and send only one response. Is there a reason it doesn't behave in that manner today?

It could be done, but it is tricky.

As it is, CommandRunner just processes the subject and up to
DEFAULT_MAIL_COMMANDS_MAX_LINES (default 25) body lines one at a time
until it gets a non-command or error except non-commands or errors in
the subject are OK. If it gets a subscribe command for a member, it's
an error, but if subscribe requires confirmation or approval, the
subscribed address won't be a member when the second request is

Note that it is perfectly valid to have multiple subscribe commands in
one message as each command can request subscription of a different

So, in order to avoid accepting a second subscribe request for the same
address, we could look at all the pending subscriptions and see if we
have one for this address, but even then we can't just ignore this
request as it might be intentional (say the confirmation email from
the prior request was lost) so we'd have to make a decision based on
how recent the prior request was. It seems like a lot of effort for
something that occurs infrequently and does no real harm.

Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan

More information about the Mailman-Users mailing list