Relaying to SPF protected server
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From: ram on 2 Apr 2010 04:54 On Thu, 2010-04-01 at 12:14 +0000, Simon Waters wrote: > On Thursday 01 April 2010 12:38:29 J.R.Ewing wrote: > > > > Is there any solution? > > I have idea to move senders address to "reply to" field and write new > > sender. Is it possible with postfix? > > As Ralph says SRS will do this. > > However I looked at this recently for a project, where I thought I'd need SRS, > and after reviewing the various issues and SPF adoption figures, concluded > I'd ignore SPF. > > In particular very few people reject outright on SPF failure (not least this > isn't a good strategy compared to other filtering methods if all you want to > do is reduce spam). Various systems handle SPF failed email in a more > suspicious manner, but that isn't a practical problem in my experience. > > SRS might work better for your purpose, but SPF is broken by design and you > should flag that to the people using it. > > We forward a lot of email, we don't do envelope rewriting, and have had a > handful of complaints over the years, most from the same person who didn't > seem to understand "we have no plans to change at this time". SPF if not the only reason why you would need SRS. We provide SMTP relay for various mail servers. I want to make sure that every customer uses only his domain(s) and sends the mail. Important to implement proper usage reporting as well as stop abuse of network Thanks Ram PS: SPF is used by gmail,hotmail, aol and 40% of the fortune 500 companies in the world among a huge lot of others. I dont think it makes any sense to flag anything like "SPF is broken" to so many people. Anyway discussing rising SPF adoption and the unreasonable arguments against SPF is OT on the postfix mailing list.
From: Wietse Venema on 2 Apr 2010 08:12 ram: > > On Thu, 2010-04-01 at 12:14 +0000, Simon Waters wrote: > > On Thursday 01 April 2010 12:38:29 J.R.Ewing wrote: > > > > > > Is there any solution? > > > I have idea to move senders address to "reply to" field and write new > > > sender. Is it possible with postfix? Postfix supports DKIM, DomainKeys, SPF, SRS, SenderID, etc., etc., via Milter plugins or SMTP-based content filters. Wietse
From: Jose Ildefonso Camargo Tolosa on 3 Apr 2010 11:09 Hi! This is getting interesting..... How, exactly, does mailman (or other mailing list manager) handles this? I mean, I have seen several SPF-enabled domains, and these domains have subscriptions to one or more lists... now, reading the headers for one of the messages of this lists, I got this: Sender: owner-postfix-users(a)postfix.org So... my guess is that the SPF check will go against this mail address, not the one on the From field..... am I right? What do you think? lldefonso Camargo
From: Sahil Tandon on 3 Apr 2010 12:38 On Sat, 03 Apr 2010, Jose Ildefonso Camargo Tolosa wrote: > So... my guess is that the SPF check will go against this mail > address, not the one on the From field..... am I right? SPF is against the ENVELOPE, not the HEADER. -- Sahil Tandon <sahil(a)tandon.net>
From: Wietse Venema on 3 Apr 2010 15:21
Jose Ildefonso Camargo Tolosa: > Hi! > > This is getting interesting..... How, exactly, does mailman (or other > mailing list manager) handles this? I mean, I have seen several > SPF-enabled domains, and these domains have subscriptions to one or > more lists... now, reading the headers for one of the messages of this > lists, I got this: > > Sender: owner-postfix-users(a)postfix.org > > So... my guess is that the SPF check will go against this mail > address, not the one on the From field..... am I right? > > What do you think? SPF uses the address in MAIL FROM command. This is sent before the RCPT TO command and before the message header/body. Wietse |