Jayson Smith writes: > Recently I've been getting lots of very similar spam.
Dunno about such spam. A lot of the spam I get has similar attributes, but I've never investigated. Maybe somebody else has. > My question is, are there any negative consequences I might face > for disabling delivery to these addresses by returning 5xx delivery > failure messages during the SMTP stage? I know there are a few > RFC's which specify that postmaster@ must be a valid address at all > domains. "Being a valid address" isn't well-defined, but RFCs tell you how to communicate data. They never tell you what to do with received data. Whether to do "something appropriate" with mail received by postmaster is a business decision, the RFCs don't care. I don't see how returning an appropriate 5xx (typically 550 Administratively Denied, with enhanced code 5.7.1) as soon as you know the sender and recipient is any less conformant than discarding the full message after sending 250 OK. The postmaster mailbox is valid and it's being processed appropriately for your policy. Senders who haven't abused your system will get through. Seems cromulent to me. > Are there any Email or other systems that actually care about > this, and will declare me to be an evil, non-compliant server > administrator if such addresses do not accept mail? Probably ;-), but nobody sane would. There are researchers who check for RFC conformance, prevalence of various protocol features, and the like, but they're highly unlikely to send you specifically formatted spam to get on your deny list in advance. In any case, if they come from consistent IPs and you firewall those IPs away from port 25 (or all ports, for that matter), the requirement that postmaster be a valid mailbox is moot. :-) Specifically, there is no requirement that any Internet address be able to receive mail. -- GNU Mailman consultant (installation, migration, customization) Sirius Open Source https://www.siriusopensource.com/ Software systems consulting in Europe, North America, and Japan ------------------------------------------------------ Mailman-Users mailing list -- mailman-users@python.org To unsubscribe send an email to mailman-users-le...@python.org https://mail.python.org/mailman3/lists/mailman-users.python.org/ Mailman FAQ: http://wiki.list.org/x/AgA3 Security Policy: http://wiki.list.org/x/QIA9 Searchable Archives: https://www.mail-archive.com/mailman-users@python.org/ https://mail.python.org/archives/list/mailman-users@python.org/ Member address: arch...@jab.org
