From b5896ba9f6047e7031e2bdee0622d543e11a6734 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 6 May 2024 03:46:30 +0200 Subject: Adding upstream version 3.4.23. Signed-off-by: Daniel Baumann --- html/LOCAL_RECIPIENT_README.html | 180 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 180 insertions(+) create mode 100644 html/LOCAL_RECIPIENT_README.html (limited to 'html/LOCAL_RECIPIENT_README.html') diff --git a/html/LOCAL_RECIPIENT_README.html b/html/LOCAL_RECIPIENT_README.html new file mode 100644 index 0000000..3f2e042 --- /dev/null +++ b/html/LOCAL_RECIPIENT_README.html @@ -0,0 +1,180 @@ + + + + + + +Rejecting Unknown Local Recipients with Postfix + + + + + + + +

Rejecting Unknown Local Recipients with Postfix

+ +

Introduction

+ +

As of Postfix version 2.0, the Postfix SMTP server rejects mail +for unknown recipients in local domains (domains that match +$mydestination or the IP addresses in $inet_interfaces or +$proxy_interfaces) with "User unknown in local recipient table". +This feature was optional with earlier Postfix versions.

+ +

The good news is that this keeps undeliverable mail out of your +queue, so that your mail queue is not clogged up with undeliverable +MAILER-DAEMON messages.

+ +

The bad news is that it may cause mail to be rejected when you +upgrade from a Postfix system that was not configured to reject +mail for unknown local recipients.

+ +

This document describes what steps are needed in order to reject +unknown local recipients correctly.

+ +

Configuring local_recipient_maps +in main.cf + +
When you need to change the local_recipient_maps +setting in main.cf + +
Local recipient table format + +

+ +

Configuring local_recipient_maps +in main.cf

+ +

The local_recipient_maps parameter specifies lookup tables with +all names or addresses of local recipients. A recipient address is +local when its domain matches $mydestination, $inet_interfaces or +$proxy_interfaces. If a local username or address is not listed in +$local_recipient_maps, then the Postfix SMTP server will reject +the address with "User unknown in local recipient table".

+ +

The default setting, shown below, assumes that you use the +default Postfix local(8) delivery agent for local delivery, where +recipients are either UNIX accounts or local aliases:

+ +

+/etc/postfix/main.cf:
+    local_recipient_maps = proxy:unix:passwd.byname $alias_maps
+

+ +

To turn off unknown local recipient rejects by the SMTP server, +specify:

+ +

+/etc/postfix/main.cf:
+    local_recipient_maps =
+

+ +

That is, an empty value. With this setting, the Postfix SMTP +server will not reject mail with "User unknown in local recipient +table". Don't do this on systems that receive mail directly +from the Internet. With today's worms and viruses, Postfix will +become a backscatter source: it accepts mail for non-existent +recipients and then tries to return that mail as "undeliverable" +to the often forged sender address.

+ +

When you need to change the local_recipient_maps +setting in main.cf

+ +

Problem: you don't use the default Postfix local(8) + delivery agent for domains matching $mydestination, $inet_interfaces, + or $proxy_interfaces. For example, you redefined the + "local_transport" setting in main.cf.
+ +
Solution: your local_recipient_maps setting needs to specify + a database that lists all the known user names or addresses + for that delivery agent. For example, if you deliver users in + $mydestination etc. domains via the virtual(8) delivery agent, + specify:
+ +
```
+/etc/postfix/main.cf
+    mydestination = $myhostname localhost.$mydomain localhost ...
+    local_transport = virtual
+    local_recipient_maps = $virtual_mailbox_maps
+
```
+ +
If you use a different delivery agent for $mydestination + etc. domains, see the section "Local recipient + table format" below for a description of how the table + should be populated.
+ +
Problem: you use the mailbox_transport or fallback_transport + feature of the Postfix local(8) delivery agent in order to + deliver mail to non-UNIX accounts.
+ +
Solution: you need to add the database that lists the + non-UNIX users:
+ +
```
+/etc/postfix/main.cf
+    local_recipient_maps = proxy:unix:passwd.byname, $alias_maps,
+        <the database with non-UNIX accounts>
+
```
+ +
See the section "Local recipient table + format" below for a description of how the table should be + populated.
+ +
Problem: you use the luser_relay feature of the Postfix + local delivery agent.
+ +
Solution: you must disable the local_recipient_maps feature + completely, so that Postfix accepts mail for all local addresses: +
+ +
```
+/etc/postfix/main.cf
+    local_recipient_maps =
+
```
+ +

+ +

Local recipient table format

+ +

If you use local files in postmap(1) format, then +local_recipient_maps expects the following table format:

+ +

In the left-hand side, specify a bare username, an +"@domain.tld" wild-card, or specify a complete "user@domain.tld" +address.
+ +
You have to specify something on the right-hand side of +the table, but the value is ignored by local_recipient_maps. + +

+ +

If you use lookup tables based on NIS, LDAP, MYSQL, or PGSQL, +then local_recipient_maps does the same queries as for local files +in postmap(1) format, and expects the same results.

+ +

With regular expression tables, Postfix only queries with the +full recipient address, and not with the bare username or the +"@domain.tld" wild-card.

+ +

NOTE: a lookup table should always return a result when the address +exists, and should always return "not found" when the address does +not exist. In particular, a zero-length result does not count as +a "not found" result.

+ + + + -- cgit v1.2.3