Re: recipient rewrite when sender !=
Wietse Venema wietse at porcupine.org writes: First of all, thanks for the answer. The Postfix instance before the content filter uses sender_dependent_default_transport_maps to send mail with a null sender to the first smtp transport, and everything else to the second smtp transport. One question: since sender_dependent_default_transport_maps overrides default_transport, how can I have this within a relay domain configuration? The transport in use would be relay_transport, IIRC. Besides, I don't see any difficulties in doing this with one single postfix instance, i.e. without an after-queue filter. Is this correct? If the above seems reasonable, then I or someone else can draft an example configuration. That would be great, I think we could discuss better with real confs at hand. Thanks, Fabio
Re: recipient rewrite when sender !=
Fabio Sangiovanni: Wietse Venema wietse at porcupine.org writes: First of all, thanks for the answer. The Postfix instance before the content filter uses sender_dependent_default_transport_maps to send mail with a null sender to the first smtp transport, and everything else to the second smtp transport. Both first and second smtp transport sending mail to the content filter. One question: since sender_dependent_default_transport_maps overrides default_transport, how can I have this within a relay domain configuration? The Postfix instance before the content filter sends *all mail* to the content filter. This simplifies routing considerably. Besides, I don't see any difficulties in doing this with one single postfix instance, i.e. without an after-queue filter. Is this correct? Perhaps, if you know how to deliver mail from to external recipients, to internal recipients, and to local recipients. If the above seems reasonable, then I or someone else can draft an example configuration. That would be great, I think we could discuss better with real confs at hand. OK, I'll look into that. Wietse
Re: recipient rewrite when sender !=
Wietse Venema wietse at porcupine.org writes: One question: since sender_dependent_default_transport_maps overrides default_transport, how can I have this within a relay domain configuration? The Postfix instance before the content filter sends *all mail* to the content filter. This simplifies routing considerably. Ok, I get it now. OK, I'll look into that. I really appreciate this, thanks. Fabio
Re: recipient rewrite when sender !=
Would it be possible to describe the problem that you are trying to solve, instead of your solution (routing senders differently). It is an uncommon requirement. Arbitrary routing requires a procedural language, which is currently not included with Postfix. Wietse
Re: recipient rewrite when sender !=
Wietse Venema wietse at porcupine.org writes: Would it be possible to describe the problem that you are trying to solve, instead of your solution (routing senders differently). It is an uncommon requirement. Arbitrary routing requires a procedural language, which is currently not included with Postfix. Wietse Yes, the problem is the following: the machine postfix is running on will act as a smtp relay for some domains. Its public ip address is listed as MX record for these domains, but inboxes are on another (internal) server. The requirements I'm trying to satisfy are: - incoming messages for some of the local addresses need to be redirected to other addresses, whose final destination is remote (so they don't need to hit the inbox) - incoming messages for these same addresses that have null sender need not to be redirected, but must be stored in the inbox (this is an exception to the previous requirement, based on the sender) Thanks a lot for your help :) Fabio
Re: recipient rewrite when sender !=
Wietse Venema: Would it be possible to describe the problem that you are trying to solve, instead of your solution (routing senders differently). It is an uncommon requirement. Arbitrary routing requires a procedural language, which is currently not included with Postfix. Your original solution was about rewriting instead of routing, but apart from that, same limitation applies. Wietse
Re: recipient rewrite when sender !=
Wietse: Would it be possible to describe the problem that you are trying to solve, instead of your solution (routing senders differently). It is an uncommon requirement. Arbitrary routing requires a procedural language, which is currently not included with Postfix. Fabio Sangiovanni: Yes, the problem is the following: [the same solution] This requires a different routing model than what Postfix currently implements. Postfix's trivial-rewrite program basically runs one address (sender or recipient) through a sequence of table lookups, without much regard to other message properties. The trivial-rewrite program is designed to be replaced by a less trivial program, but sofar that replacement has not materialized. That means your solution can currently be implemented only with less than elegant solutions. To make the point clear, below is a single Postfix configuration that rewrites selected addresses when the sender is not . It uses a sender-dependent FILTER action to enable/disable address rewriting with smtp_generic_maps, and loops mail back into Postfix via a mechanism that was designed for external content filters. /etc/postfix/main.cf: smtpd_sender_restrictions = pcre:/etc/postfix/sender_access # Default: enable smtp_generic_maps address rewriting. content_filter = smtp-with-generic:127.0.0.1:10025 /etc/postfix/sender_access: # Override: disable smtp_generic_maps address rewriting. //FILTER smtp-no-generic:127.0.0.1:10025 /etc/postfix/master.cf: # smtp-no-generic is included for clarity. You could use smtp instead. smtp-no-generic unix - - n - - smtp -o smtp_generic_maps= smtp-with-generic unix - - n - - smtp -o smtp_generic_maps=hash:/etc/postfix/generic 127.0.0.1:10025inet n - n - - smtpd -o receive_override_options=no_address_mappings /etc/postfix/generic: us...@example.com anoth...@example.org Now, this looks like a pretty compact configuration. The problem is that a) it is unlikely that real people would come up with stuff like this and b) solutions that rely on multiple parts (here, FILTER and smtp_generic_maps) tend to fall apart when requirements change. In the end, it appears that the more verbose configuration language wins. Wietse
Re: recipient rewrite when sender !=
Wietse Venema wietse at porcupine.org writes: Wietse Venema: Would it be possible to describe the problem that you are trying to solve, instead of your solution (routing senders differently). It is an uncommon requirement. Arbitrary routing requires a procedural language, which is currently not included with Postfix. Your original solution was about rewriting instead of routing, but apart from that, same limitation applies. Wietse With my original solution, do you mean the access table with REDIRECT directive? It's the first thing I came up with, but I changed my mind quite rapidly because of its poorness in dealing with multiple recipients.
Re: recipient rewrite when sender !=
Wietse Venema wietse at porcupine.org writes: In the end, it appears that the more verbose configuration language wins. Thanks, this should also get rid of the double instance + content filter. It should work properly, and let's hope requirements don't change :) Fabio
Re: recipient rewrite when sender !=
Fabio Sangiovanni: Hi list, I'm setting up postfix as mx for some domains. According to the docs, my setup should fall in the 'relay_domain' class, since I need to relay messages for those domains to an internal host (is this correct?). That is correct. When your server is not the final destination for domain X, then X is a relay domain. I need to implement a policy, that is an exception to the standard flow postfix - internal host: I need to rewrite the address of some particular recipients, but just for messages with envelope sender different from the null sender. In other terms, I need to redirect messages for some recipients in a list (towards other, remote, addresses), but only if the envelope sender is not . If the envelope sender is , I need messages to follow the standard route towards the internal host, even for the recipients on the list. I am suspicious about mail configurations that special-case bounce messages. That said, this is doable with Postfix built-in mechanisms if your setup looks like Postfix-after-queue content filter-Postfix-internal, with separate Postfix instances before and after the filter. In this case, the Postfix instance before the content filter uses two smtp transports (with different names) that both deliver all mail to the content filter. The Postfix instance before the content filter uses sender_dependent_default_transport_maps to send mail with a null sender to the first smtp transport, and everything else to the second smtp transport. The second smtp transport uses smtp_generic_maps to rewrite addresses. Note that smtp_generic_maps rewrites all addresses (both envelope and message header). Postfix after the content filter simply delivers mail to its destination, whether internal or external. If the above seems reasonable, then I or someone else can draft an example configuration. If you must implement sender-dependent recipient rewriting within one Postfix configuration, this requires a plugin. You'd need a Milter plugin (for example in Python or Perl) that deletes an old recipient and that adds a new recipient as its replacement. This Milter would not need to inspect the message body, so the overhead would be small. If you use a before-queue content filter, this Milter plugin would have to be hooked into the SMTP daemon after the filter. Wietse
