[GH-ISSUE #16] Change message subject #14

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opened 2026-02-27 15:44:57 +03:00 by kerem · 3 comments

kerem commented

2026-02-27 15:44:57 +03:00

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Originally created by @base1983 on GitHub (Jul 11, 2016).
Original GitHub issue: https://github.com/Pro/exchange-catchall/issues/16

Is it possible to change the subject with a prepend? Like subject: [NON EXISTEND USER] SUBJECT.

Originally created by @base1983 on GitHub (Jul 11, 2016). Original GitHub issue: https://github.com/Pro/exchange-catchall/issues/16 Is it possible to change the subject with a prepend? Like subject: [NON EXISTEND USER] SUBJECT.

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2026-02-27 15:44:57 +03:00

kerem commented

2026-02-27 15:44:58 +03:00

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@Pro commented on GitHub (Jul 11, 2016):

It's not yet implemented, but it would be possible.

For that functionality the config needs two additional optional fields. Something like:

<Domain name="^.*@(.*)\.catchall.com$" regex="true" address="$1@example.org">
<Fallback address="fallback@example.org" subjectPrepend="NON EXISTEND USER"/>
</Domain>

and then the signer needs to check if the user from $1 exists, somewhere here:
https://github.com/Pro/exchange-catchall/blob/master/CatchAllAgent/CatchAllAgent.cs#L217

This is the harder part: How can the transport agent check for existing users?

I'm open for suggestions or pull requests.

@Pro commented on GitHub (Jul 11, 2016): It's not yet implemented, but it would be possible. For that functionality the config needs two additional optional fields. Something like: ``` <Domain name="^.*@(.*)\.catchall.com$" regex="true" address="$1@example.org"> <Fallback address="fallback@example.org" subjectPrepend="NON EXISTEND USER"/> </Domain> ``` and then the signer needs to check if the user from `$1` exists, somewhere here: https://github.com/Pro/exchange-catchall/blob/master/CatchAllAgent/CatchAllAgent.cs#L217 This is the harder part: How can the transport agent check for existing users? I'm open for suggestions or pull requests.

kerem commented

2026-02-27 15:44:58 +03:00

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@base1983 commented on GitHub (Jul 11, 2016):

Somehow the transport agent already knows this. You send a email and it goes to the catchall only is the recepient doesn't exist.

@base1983 commented on GitHub (Jul 11, 2016): Somehow the transport agent already knows this. You send a email and it goes to the catchall only is the recepient doesn't exist.

kerem commented

2026-02-27 15:44:58 +03:00

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@Pro commented on GitHub (Jul 11, 2016):

Oh yeah, right, sorry. Forgot about this step.
So what needs to be done is to implement the code lines in here:
https://github.com/Pro/exchange-catchall/blob/master/CatchAllAgent/CatchAllAgent.cs#L190

I.e. set the replaceWith to the fallbackAddress if there is any. And if needed, update the subject.

Open for pull requests.

@Pro commented on GitHub (Jul 11, 2016): Oh yeah, right, sorry. Forgot about this step. So what needs to be done is to implement the code lines in here: https://github.com/Pro/exchange-catchall/blob/master/CatchAllAgent/CatchAllAgent.cs#L190 I.e. set the replaceWith to the fallbackAddress if there is any. And if needed, update the subject. Open for pull requests.