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postsrsd - Man Page

Postfix Sender Rewriting Scheme daemon


postsrsd -s<file> -d<domain> [other options]


Sender Rewriting Scheme implementation for Postfix.

Implements two TCP lookup tables to rewrite mail addresses as needed. The forward SRS is for sender envelope addresses to prevent SPF-related bounces. The reverse SRS is for recipient envelope addresses so that bounced mails can be routed back to their original sender.



read secrets from file (required)


set domain name for rewrite (required)


set first separator character which can be one of: -=+ (default: =)


length of hash to be used in rewritten addresses (default: 4)


minimum length of hash to accept for validation (default: 4)


set socket listen address (default:


set port for the forward SRS lookup (default: 10001)


set port for the reverse SRS lookup (default: 10002)


write process ID to pidfile (default: none)


chroot to <dir> (default: none)


switch user id after port bind (default: none)


timeout for idle client connections (default: 1800)


exclude additional domain from address rewriting


always rewrite addresses


attempt to read above parameters from environment


fork into background


force IPv4 socket (default: any)


force IPv6 socket (default: any)


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November 2022 postsrsd 1.12 System Administration Utilities