Email - Postfix transport, relay servers
Email Solution · Config document · referenced from Relay servers
The transport table of a relay server. It has one entry: mail for the site's own domain does not go to the internet but back inside, to the mailbox server.
| Item | Value |
|---|---|
| Path on the server | /etc/postfix/transport |
| Shown here | DC2-A-VCMSR001 |
| Also on | DC2-B-VCMSR001, identical (diff shows no difference) |
| Referenced by | transport_maps = hash:/etc/postfix/transport |
| Software | Postfix 2.10.1 from RHEL 7 |
| Activated with | a hash: table has to be compiled with postmap /etc/postfix/transport; the install notes do not record that command |
The file
################################################################################################### # Domain/mail_address Transport ################################################################################################### # Delivery transport to Internal Email Server 3 (DC2-A-VCMSX002) for email messages for domain @ad-dc2.example.net # Mainly non-delivery email notification ad-dc2.example.net smtp:[10.12.19.43]
The square brackets switch off the MX lookup for the next hop: the message goes to 10.12.19.43, the internal address of DC2-A-VCMSX002, and nowhere else.
Checked against Postfix 3.11.7
| As built | Today |
|---|---|
transport_maps = hash:/etc/postfix/transport | RHEL 10 no longer provides the Berkeley DB libraries, so hash: is gone there; the table becomes lmdb:/etc/postfix/transport and is built with postmap as before |
| Package | postfix-lmdb is part of RHEL 9 since 9.3 and of RHEL 10 |
Postfix 3.11 documents the migration in its NON_BERKELEYDB_README.