Comcast and mail header errors?

[Paul Lussier]

Hi all,

Anyone seen the following type of header coming though Comcast's servers?
 
  Received: from some.host.com \
  (someother.host.com[192.168.10.100](misconfigured sender))

The hostname and ip's have been changed.  I'm fairly certain that this
is NOT a misconfigured sender, as I receive e-mail with this header
from a huge number of places to multiple addresses.  The only one
which have this "misconfigured sender" tag are those coming in through
comcast.  My gmail account doesn't have them, nor do the messages I
see in gmane.

I'd love an explanation as to why Comcast thinks the senders are
misconfigured... (above and beyond "Comacast sucks" and the other
various, unhelpful epithets likely to be uttered :)

-- 

Seeya,
Paul