Bernd Wurst wrote: > If one of my customers > forwards mail to his other account at some other company, the destination > server rejects my message because the sender's address is still set to the > original sender (that sent the message to me) and I am not listed as a valid > sender for the sender's domain.
Another reason why it can reject the message is because your customer's other account at that company has been canceled. What do you do then? > That's a really common scenario and requires that the forwarding mail server > rewrites the envelope sender to end up in his own domain that allows him to > send mail (SPF-wise). > > But simply rewriting the sender breaks automatic bounce processing. Assume, for example, that your customer above subscribed to a mailing list. After the other company cancels his mailbox there, messages from the mailing list will generate bounces after you forward them. If you forward the bounces to the mailing list's bounce address, your customer subscription will be canceled (automatic processing of bounces.) Thus, the mailing list would operate a cancellation of [EMAIL PROTECTED] as a consequence of canceling [EMAIL PROTECTED] company*. Is that behavior always correct? > For sure, I could use some per-user-script outside the mail server that does > SRS (or any similar way) but that's not really easy to maintain. Forwarding rules have never been easy to maintain. >>> SPF standalone doesn't really help anything. >> It helps the owner of a domain to avoid that others abuse of it. > > And causes that his mail not to be forwarded if the destination is just a > forward to another host and the forwarder does no sender rewriting. > > I meant "SPF without widespread SRS" when I wrote "SPF standalone". I still hold that full blown SRS is only required in case fully automated bounce processing is needed. In the example above, SRS would result in a backscatter machine, much like other customer-written rules that reject messages during the delivery stage. As an alternative to forwarding, your server may reply at the SMTP stage 551 User not local; please try <[EMAIL PROTECTED] company> Or, if the other company supports whitelisting, your customer should whitelist your machine before writing his forwarding rule on it. ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ courier-users mailing list [email protected] Unsubscribe: https://lists.sourceforge.net/lists/listinfo/courier-users
