Wietse Venema wrote: > John Peach: >> On Mon, 03 Aug 2009 13:18:52 +0200 >> Robin Smidsr__d <ro...@smidsrod.no> wrote: >> [snip] >>> Willy De la Court wrote: >>> >>> >>> Does this mean that all of the reject rules are in fact not >>> RFC-conformant? >>> >>> The reason I mention reject_invalid_helo_hostname is that I'm unsure >>> if the IPv(4|6) address syntax is part of this rule (postfix version >>> 2.5.5, distributed with ubuntu 9.04). >>> >>> What about the two other reject rules? As far as I can tell, they are >>> both non-conformant. >> Your server, your rules. > > Indeed. RFCs are relevant only when parties want to interoperate. > Generally, there is no such desire on the receiving end of SPAM.
I'm just trying to figure out what to write in a policy document about this behaviour. A behaviour which is backed by a RFC has a lot of more weight (conserning interoperability) than our own policies about what is accepted behaviour or not. When a legitimate server is rejected it is generally easier to say "the admin of that server has not set up his server correctly according to the standard. Make him fix it if you want to receive email from them." than it is to say "our policies does not allow a connection like that because the email is usually spam". The last one is a tempting reason for a customer to leave and find another service provider (because it rejects legitimate email). Whitelisting is (usually) a manual job, and anything that is manual work requires human intervention (i.e. usually not something you want). What does the reject_invalid_helo_hostname rule do with the IPv(4|6) HELO response? I mean, when the "domain" looks like [10.1.2.3] or [::1]? Does it accept or reject it? According to the RFC it should be valid. reject_non_fqdn_helo_hostname means that the "domain" needs to contain at least a dot, and otherwise conform to the DNS naming standards, am I correct? Will this rule short-circuit *accept* a IPv4/6 "domain", as defined above, or will it reject it? If you don't use these reject rules, will warnings (as suggested by the RFCs) be inserted in the Received: line (or somewhere else in the header)? If it is I can use this as input to a mail filter. Regards, Robin, which is trying to build a mail system which puts the choice of rejecting/filtering email in the hands of the end user.
