[Mailman-Developers] Potential risk of VERP?

Peter Watkins peterw@usa.net
Tue, 12 Feb 2002 13:54:22 -0500

On Tue, Feb 12, 2002 at 01:24:08PM -0500, Barry A. Warsaw wrote:

> Let's say I run a mailing list foo@python.org and someone like (oh, I
> dunno) yahoogroups subscribes to the list and provides subscription
> services of its own.

> Now, suppose someone on foo@yahoogroups.com starts bouncing, and we're
> VERPing.  Won't our Mailman think that foo@yahoogroups.com is the
> bouncing member?

> Or will/should yahoogroups rewrite the envelope sender for /its/
> downstream members?

They should do that, and also do things like discard all the Received 
headers so that yahoo subscribers don't bouce the mail due to "too many 
hops" restrictions on downstream MTAs. In a sense, whether a mailing list 
package uses VERP or provides individualized X-List headers (which should 
also be manipulated), or visible URLs in the message body, the reality is 
that many mailing list packages send out messages whose contents are 
intended for a specific indivdual. Anyone who wants to "reflect" a list
will need to deal with any such customized headers or content if they want 
to keep their subscribers happy. This problem affects more than simply 
VERPed messages, and it's not the primary/top/initial mailing list's 
responsibility to "fix" the problem, IMO.


We must all learn to live together as brothers,
or we will all perish as fools. - Dr Martin Luther King, Jr