[SOLVED] Configure Postfix SMTP Relay with sender_canonical_maps

synner · 05-05-2018, 04:23 AM

Hello, fellas

I have a couple of servers in a private LAN 10.0.0.0/24.
I've set up one of the servers with Postfix in a effort to relay internal mails to an external SMTP server (of my ISP).

Every server in my LAN runs a variety of test apps (in a lab-like environment) and they send out various mail notifications and reports. Every app's settings for mail sender are (usually) in the form of <app>@lab.local but it can be anything, really.

My question boils down to how to configure Postfix to perform the following rewrite in the SMTP envelope and not header.

<myapp>@<randomlocal.domain> ----> <myapp>.<randomlocal.domain>@mylegitinternetdomain.com
And then relay it to the external ISP SMTP.

Recipients' SMTP envelope and header should not get modified.

I got so far:
/etc/postfix/main.cf

Code:

smtpd_banner = $myhostname ESMTP $mail_name ($mail_version)
smtpd_helo_required = yes

inet_interfaces = 127.0.0.1, 10.0.0.1
inet_protocols = ipv4

relayhost = [smtp.myisp.com]

myhostname = mail.lab.local
mydomain = lab.local

myorigin = $mydomain
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain

mynetworks_style = subnet
mynetworks = 127.0.0.0/8, 10.0.0.0/24

append_at_myorigin = no
append_dot_mydomain = no

local_header_rewrite_clients = permit_inet_interfaces, permit_mynetworks, reject
remote_header_rewrite_domain = domain.invalid

masquerade_domains = $mydomain

sender_canonical_classes = envelope_sender
sender_canonical_maps = regexp:/etc/postfix/canonical_maps_sender

/etc/postfix/canonical_maps_sender

Code:

if !/@mylegitinternetdomain\.com/i
/^.*?([^\s<]+?)@([^\s>]+?)>?\s*$/i      ${1}.${2}@mylegitinternetdomain.com
endif

My regex seems to be wrong as in my Inbox from the ISP SMTP I get mails from "lab.local"@mylegitinternetdomain.com

Help!!!

What am I missing?

Thank you in advance!

synner · 05-28-2018, 03:36 AM

Postfix's Regex engine seems rather pretentious. Seems it does not fancy complex regex.
After numerous tests, went back to basics, gradually introduces complications, finally managed achieve my goal with:

Code:

root@mailsrv:/etc/postfix # cat canonical_maps_sender
if !/.+?@myinetdomain\.com/i
/(.+?)@(.+)/i           ${1}\.${2}@myinetdomain\.com
endif

Problem solved, I guess...