Difficulty creating a "nobody@" address

[Tim Smith]

Hi,

I’m trying to create a “nobody@“ email address for outbound-only
transaction confirmations that will /dev/null any attempts to email
it.

In my main.cf on the inbound mail gateway I have:
relay_recipient_maps = ${indexed}XYZ_relay_recipients

And in the map file I have :
nob...@example.com DISCARD

Make tables, reload etc.  but then it doesn’t seem to work ?

   <nob...@example.com>: Recipient address rejected: User unknown in
   virtual mailbox table (in reply to RCPT TO command)


Perhaps I’m mis-interpreting the purpose of relay_recipient_maps ? If
so, what should I be using instead ?  Bear in mind that as mentioned
above, this is a mail gateway, mails are not stored locally on these
machines but forwarded on to internal ones.

Thanks


Tim