postmap
Create and query Postfix lookup tables
TLDR
SYNOPSIS
postmap [options] [filetype:]name_
DESCRIPTION
postmap creates and queries Postfix lookup tables. It converts plain text files containing key-value pairs into indexed database formats (hash, btree, dbm) for efficient lookups by the Postfix mail system. Common uses include virtual alias maps, transport maps, and access control tables.After editing a text lookup file, postmap must be run to rebuild the corresponding .db file that Postfix actually reads. The query mode (-q) allows testing individual lookups, and the show mode (-s) displays all entries, both useful for verifying that mappings work as expected before applying them to live mail delivery.
PARAMETERS
-q key
Query for key.-s
Show all entries.-d key
Delete key.-i
Incremental mode.-N
Include the table name as part of a lookup key or value.-w
Wait for locked files.
EXAMPLES
postmap /etc/postfix/virtual
# Create transport map
postmap hash:/etc/postfix/transport
# Query specific entry
postmap -q "user@example.com" /etc/postfix/virtual
# Show all mappings
postmap -s /etc/postfix/virtual
# Delete entry
postmap -d "olduser@example.com" /etc/postfix/virtual
FILE FORMAT
user@example.com localuser
@example.com catchall@other.com
INSTALL
CAVEATS
Run postmap after editing text files. Postfix reads .db file, not text. Use postmap -q to verify.
HISTORY
postmap is part of Postfix, the mail transfer agent created by Wietse Venema as a secure alternative to Sendmail.
SEE ALSO
postconf(1), postfix(1), postqueue(1), newaliases(1)
