The Sender Rewriting Scheme preserves .forward functionality in an SPF-compliant world. SPF requires the SMTP client IP to match the envelope sender (return-path). When a message is forwarded through an intermediate server, that intermediate server may need to rewrite the return-path to remain SPF compliant. If the message bounces, that intermediate server needs to validate the bounce and forward the bounce to the original sender. SRS provides a convention for return-path rewriting which allows multiple forwarding servers to compact the return-path. SRS also provides an authentication mechanism to ensure that purported bounces are not arbitrarily forwarded.
Binary packages can be installed with the high-level tool pkgin (which can be installed with pkg_add) or pkg_add(1) (installed by default). The NetBSD packages collection is also designed to permit easy installation from source.
The pkg_admin audit command locates any installed package which has been mentioned in security advisories as having vulnerabilities.
Please note the vulnerabilities database might not be fully accurate, and not every bug is exploitable with every configuration.
Problem reports, updates or suggestions for this package should be reported with send-pr.