Making reverse lookups work

[michaellunsford]

well, this might not be plesk related -- but I don't know where else to post it.

I used to get the "possible break-in attempt" error when logging into SSH. Apparently the ISP has fixed this (for the moment) -- but it'll probably be back tomorrow.

One thing that's still "broke" is email. Any external email addresses receiving mail from my server will show my IP address "may be forged" in their headers.

Received: from server.example.com
(ds209-253.ipowerweb.com [xxx.xxx.xxx.xxx] (may be forged))
by ...com (Xserve/smtpin20/MantshX 4.0) with ESMTP id ...

how do I make the "may be forged" go away?

Are there any other areas I should be looking to fix regarding this reverse lookup thing?