While analysing the pole setters in our internal bouncers-Hitlist i found that some of them run a mail2news-Gateway.

The problem is: our Mailinglists leave Mail-Headers mostly untouched, and so headers like X-Trace or X-Complaints-To are passed through without modifications.

If a mail containing those headers is handed over to inews (as in INN) it rejects it, and the bounce comes back to us:

<XXXXX@XXX.com>: Command died with status 1: "/usr/bin/maildrop". Command
output: inews: cannot send article to server: 441 Can't set system
"X-Complaints-To" header inews: article not posted

so people: fix your systems. if you do more with listmail than dropping it somewhere make sure that the bounces your system produces go to someone who can fix it. We (as in listmasters) normally simply unsubscribe those.

btw: we talk about 18181 bounces since 08.2004 in this case.