Am 30. April 2019 09:08:34 MESZ schrieb Thomas Walter via mailop <mailop@mailop.org>:
>We have a lot of students forwarding their emails to external mailboxes >(usually freemailers even though they have more options here). > >I can show you all kinds of examples where the forwarding is rejected >in >those cases because the new "sending IPs" are from our machines, not >the >ones listed in the From's SPF record. > Same envelope forwarding is broken and has been broken for a long time, not at all related to SPF. 1. The majority of mail senders can hardly decipher a NDN, let alone a NDN for an address they didn't send to. They ignore it, reply to the Mailer-Daemon, or seek for help. 2. The original sender can never fix the problem. 3. Many misguided mail servers refuse all messages with an empty envelope sender, ignoring the RFC and the fact that there are a few other reasons than late bounces. The same mail servers tend to send many mails that ask for reading notifications. Forwarding usually produces late bounces. 4. There are obvious privacy problems with bounces after forwarding. 5. On the other hand, the forwarder usually can fix the problem, but doesn't get informed of it with same address forwarding. My recommendation is to forward with a variant of the forwarders address that doesn't get forwarded (to prohibit loops). SRS has all the same problems, btw. Jost _______________________________________________ mailop mailing list mailop@mailop.org https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop
