Date: Sun, 20 Oct 1996 17:33:29 +0200 (IST) From: Nadav Eiron <nadav@barcode.co.il> To: "Timothy P. Layton, Sr." <tlayton@global-sol.com> Cc: questions@FreeBSD.ORG Subject: Re: HELP !!! I have a mail hacker. Message-ID: <Pine.BSF.3.91.961020172724.12781A-100000@gatekeeper.barcode.co.il> In-Reply-To: <199610190913.JAA07351@global-sol.com>
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On Sat, 19 Oct 1996, Timothy P. Layton, Sr. wrote: > Help !!! > > my mail host is receiving a couple thousand messages per night > from a ficticous user at a fake domain. > > I looked in the maillog and found what domain the messages where > coming from. > > Can I reject all mail from a single domain, and can I take it even > further by refusing any type of connection from a domain ?? I think you've just discovered you need a firewall... As an immediate action, look into ipwf (if you're running 2.1.5 or up - it's much improved since 2.1.0). Use it to block out things you don't need. Then, especially if you have a network of machines to protect, build a firewall. It is pretty easy to do. I recommend reading: Firewalls and Internet Security by Cheswick and Bellovin (ISBN: 0-201-63357-4), published by Addison-Wesley. It is a bit old, but *very* well written, built upon real world experience, and has pointers to free firewall resources on the 'net. One of the great motos of this book (and many others on security) is: Don't let anyone from the outside even get at your sendmail. Sendmail is far too complex to be bug-free, and the Bad Guys will use those bugs. The TIS firewall toolikit (it's in the ports collection) has a wrapper for sendmail (made of two programs: smap and smapd). > > Please Help ! > > Thanks > Tim- > -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > Timothy P. Layton, Sr. > http://www.global-sol.com > mailto:tlayton@global-sol.com > voice:314.298.0873 Fax:314.298.8482 > -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > Nadav
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