Tips and Tricks for sendmail Hackers

Last Update 2006-03-31


sendmail contains many FFRs (For Future Release). If you're brave enough, you may want to try some of those. But be aware: they are not supported, not documented, and they may go away in the next release. Before you try to use any of these, check the code whether the FFR still exists in your sendmail version. You may also find new FFRs that you might want to try.


Removed, sendmail has its own I/O layer since 8.12.


_FFR_TLS_1 enables some nice additional STARTTLS related features:


Removed, srv_features and try_tls are available.


Enabled in 8.12 and later.


Enabled in 8.12 and later.
[(links)] [Hints] [Avoiding UBE] [cf/README] [New]
Copyright © Claus Aßmann Please send comments to: <ca at>
Disclaimer: the information provided may be inaccurate or outdated or incomplete. Please contact me if you find an error.