Sorry to rehash this old thread, however, this is a concern and while I think I know the answer, that's on an assumption that I don't want to make. So let me phrase a question more specifically that will answer this:

If Gossamer Mail is running on gmaildomain.com and sendmail is piping to incoming.pl, and an e-mail is addressed as follows:

To: someuser@somedomain.com
Bcc: someuser@gmaildomain.com

Will someuser@gmaildomain.com receive the message? Obviously, his address, someuser@gmaildomain.com WILL NOT appear anywhere in the headers of the e-mail. I am not familiar enough with sendmails pipe to external program process to know if it pipes the entire SMTP transaction (which would include the recipients address) or just the message itself (in which case I would expect the the message would not be properly delivered).

Thanks for the response.