"Errors-To:" is not a standard RFC822 header and not the correct way to tell a mailer where to send delivery errors. Internet mail messages have two headers, a RFC822 header which is preserved as the message is delivered to the user, and a RFC821 header which is discarded upon delivery and used by the mailers to talk to each other. This is how the mailers know to deliver the message to you even though the header says "To: LSTOWN-L". This RFC821 header also says where the delivery errors should be returned (normally owner-listname@listhost). When LISTSERV gets the error, it checks the list header and processes as desired. Many mail systems (and in particular gateways) ignore the RFC821 error address, especially when gating to a system that does not support that concept (ie where errors, replies, and everything else goes to the "From:" address). In that case there is nothing you can do. Eric