Is anyone here a qmail pro?

I set up qmail on my box using the Mail Admin HOWTO which gave me the
quick and cheesy way to set up qmail.  It worked great, except it wouldn't
route mail from the TLD.

hostname.domain.com

I could send mail between users at host.domain.com, but users at domain.com
wouldn't route.  This machine wasn't on a network so I couldn't test
outside mail routing.

Then I did something really stupid.  I went into /etc/sysconfig/network
and changed my hostname.domain.com.  After reconfiguring qmail, nothing
works.  

I did the ./config-fast host.domain.com so it updated all the
/var/qmail/control/ files and a cat /var/qmail/control/* all looks good.
Any idea why it wouldn't route to the TLD and now it won't send at all?

-Brian