[Lilux-help] customizing "unknown user" bounce mail from sendmail

[Eric Dondelinger]

Hi,

I'd like to customize the error message sent back to the sender
when a "unknown user" is encountered.

By default sendmail generates something like this:

>From: Mail Delivery Subsystem
><MAILER-DAEMON at some.domain.lu>
>To: <sender at some.other.domain>
>Subject: Returned mail: see transcript for details
>Date: whatever
>
>The original message was received at <date>
>from [a.b.c.d]
>
>    ----- The following addresses had permanent fatal errors -----
><recipient at domain.lu>
>     (reason: 550 recipient at domain.lu... No such user)
>
>    ----- Transcript of session follows -----
>... while talking to [b.c.d.e]:
> >>> DATA
><<< 550 recipient at domain.lu... No such user
>550 5.1.1 <recipient at domain.lu>... User unknown
><<< 503 Issue RCPT TO: command before DATA command

Final-Recipient: RFC822; recipient at domain.lu
Action: failed
Status: 5.1.1
Remote-MTA: DNS; [a.b.c.d]
Diagnostic-Code: SMTP; 550 recipient at domain.lu ... No such user
Last-Attempt-Date: sometime


So I'd like to customize the message (especially get rid of IP
addresses so as not to reveal topology information of the
internal network).
Does anyone have an idea on how to go about this? Is there some
config file to edit (vi /etc/mail/sendmail.cf anyone? :-)) or
something?

My googling hasn't been very successful so far...

TIA, Eric