posts:postfix: use smtp_generic_maps instead of sender_canonical_maps.

Thanks to David Craig (0x94081B81) for suggesting the shift from
canonical to generic.

I also:

* Switched from hash- to regexp- tables, because I'm mapping all
  outgoing mail to the same From address.
* Added links for the various configuration parameters.
* Wrapped the first "Incoming mail" paragraph.

diff --git a/posts/Postfix.mdwn b/posts/Postfix.mdwn
index e1fafaf0abfefb0c7c7132c56554bb6417ef0f31..5c28a0990a1f82255dfdad907e437edd3e5583b8 100644 (file)
--- a/posts/Postfix.mdwn
+++ b/posts/Postfix.mdwn
@@ -18,19 +18,16 @@ free local port.
     # cat /etc/postfix/main.cf
     myhostname = mail.example.com
     relayhost = [127.0.0.1]:12345
+    smtp_generic_maps = regexp:/etc/postfix/generic
     smtp_sasl_auth_enable = yes
     smtp_sasl_password_maps = hash:/etc/postfix/saslpass
-    sender_canonical_maps = hash:/etc/postfix/sender_canonical
+    …
+    # cat /etc/postfix/generic
+    /^(.*)@(.*)$/ jdoe@example.com
+    # postmap /etc/postfix/generic
     # cat /etc/postfix/saslpass
     [127.0.0.1]:12345 jdoe@verizon.net:YOURPASS
     # postmap /etc/postfix/saslpass
-    # cat /etc/postfix/sender_canonical
-    root@mail.example.com jdoe@example.com
-    root@example.com jdoe@example.com
-    root@localhost jdoe@example.com
-    jdoe@mail.example.com jdoe@example.com
-    jdoe@localhost jdoe@example.com
-    # postmap /etc/postfix/sender_canonical
     # cat /etc/stunnel/stunnel.conf
     [smtp-tls-wrapper]
     accept = 12345
@@ -50,15 +47,23 @@ Here's what's going on:
 * Stunnel picks up the connection from Postfix, encrypts everything,
   and forwards the connection to port 465 on `outgoing.verizon.net`
   (`stunnel.conf`).
-* Postfix identifies itself as `mail.example.com` (`myhostname`), and
+* Postfix identifies itself as `mail.example.com` ([myhostname][]), and
   authenticates using your Verizon credentials (`smtp_sasl_…`).
 * Because Verizon is picky about the `From` addresses it will accept,
-  we use `sender_canonical` to map addresses to something simple that
-  we've tested.
+  we use [smtp_generic_maps][] to map addresses to something simple
+  that we've tested.
 
 And that's it :p.  If you're curious, there's more detail about all
-the Postfix config options in the [postconf][] man page, and there's
-good SASL information in the [SASL_README][].
+the Postfix config options in the [postconf][] man page.  You might
+also want to look over the [SASL_README][] and
+[ADDRESS_REWRITING_README][].
+
+For the [generic][] mapping, I've used a [regexp table][regexp], that
+way I don't have to map a bunch of possible original addresses by
+hand.  By using [smtp_generic_maps][] instead of [canonical_maps][],
+we only remap addresses before they head off into the wider world.  If
+we used [canonical_maps][], we would remap all incoming mail, even
+mail destined for local delivery.
 
 There's also a [blog post by Tim White][TW] which I found useful.
 Because Verizon lacks [STARTTLS][] support, his approach didn't work
@@ -67,7 +72,9 @@ for me out of the box.
 Incoming mail
 =============
 
-In case you have trouble with someone blocking your incoming mail, things are a bit trickier.  You can always accept mail on different ports (e.g. the submission port 587), with an entry like
+In case you have trouble with someone blocking your incoming mail,
+things are a bit trickier.  You can always accept mail on different
+ports (e.g. the submission port 587), with an entry like
 
     submission inet n - n - - smtpd
 
@@ -95,8 +102,14 @@ see the [Postfix suggestions for being an MX host for a remote
 site][host].
 
 [Postfix]: http://www.postfix.org/
+[myhostname]: http://www.postfix.org/postconf.5.html#myhostname
+[smtp_generic_maps]: http://www.postfix.org/postconf.5.html#smtp_generic_maps
 [postconf]: http://www.postfix.org/postconf.5.html
 [SASL_README]: http://www.postfix.org/SASL_README.html
+[ADDRESS_REWRITING_README]: http://www.postfix.org/ADDRESS_REWRITING_README.html
+[generic]: http://www.postfix.org/generic.5.html
+[regexp]: http://www.postfix.org/regexp_table.5.html
+[canonical_maps]: http://www.postfix.org/postconf.5.html#canonical_maps
 [TW]: http://www.zulius.com/how-to/set-up-postfix-with-a-remote-smtp-relay-host/
 [STARTTLS]: http://en.wikipedia.org/wiki/STARTTLS
 [MX]: http://en.wikipedia.org/wiki/MX_record