how to handle this case if fetchmail fetches spam from yahoo, and postfix does not deliver because host does not exist

Question

I have fetchmail collecting from yahoo and passing the mails to the local postfix server. If I have a 4xx Error , because for example the sender domain does not exist, fetchmail will try to pas this email forever to postfix and postfix will reject it forever with

NOQUEUE: reject: RCPT from localhost.localdomain[127.0.0.1]: 450 4.1.8 <[email protected]>: Sender address rejected: Domain not found; from=<[email protected]>

first question:
how do I have to setup fetchmail to fist of all act from a local host I have set-up
fetchmail.localdomain[127.0.0.7]
in order that the logfile looks like this:

NOQUEUE: reject: RCPT from fetchmail.localdomain[127.0.0.7]: 450 4.1.8 <[email protected]>: Sender address rejected: Domain not found; from=<[email protected]>

for this I have setup /etc/hosts

127.0.0.1       localhost.localdomain   localhost
127.0.0.7       fetchmail.localdomain   fetchmail

second question:
how can I setup fetchmail to try a limited nr of times to pass the mail to postfix and after this to skip it?

Answer 1

Personally I avoid the whole local mailserver and have fetchmail running from my crontab and deliver straight to old-school procmail which in turn calls SpamAssassin, anti-virus and before filtering and dropping my mail in the correct Maildir:

poll pop.example.com with proto pop3:
        user "[email protected]" there has password "password"
        is me here and wants ssl nokeep mda "/usr/bin/procmail -t /home/me/.procmailrc"