Date: Fri, 26 Sep 2008 11:52:17 -0700 From: David Southwell <david@vizion2000.net> To: freebsd-questions@freebsd.org Cc: Chris Pratt <eagletree@hughes.net> Subject: Re: Flooded with emails to root -- URGG Message-ID: <200809261152.17840.david@vizion2000.net> In-Reply-To: <D90738EF-484A-4EEA-BB3F-E8904B9C88BB@hughes.net> References: <200809250934.57150.david@vizion2000.net> <D90738EF-484A-4EEA-BB3F-E8904B9C88BB@hughes.net>
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On Thursday 25 September 2008 09:40:34 Chris Pratt wrote: > On Sep 25, 2008, at 9:34 AM, David Southwell wrote: > > Hi > > > > I am running postfix. > > > > Am receiving a flood of emails that appear to emanate from Servers > > who have > > received spam that has masqueraded root@mydomain as the email source. > > > > Could anyone please suggest the best way of dealing with these. > > Please bear in > > mind I am not all that familiar with postfix so if anyone feels > > treating me > > like an idiot and spoonfeeding the actual command s to use I would > > be most > > appreciative <chuckles> > > I have no idea what a command would be to stop receipt. Cutting off the > original generation of the emails being spoofed is more to the point. > > You may want to look at SPF (openspf.org). If your domain is listed > with an > spf entry in DNS, you become less tempting as a domain to spoof. Over > time, it will all but cease. Once you've created an SPF DNS record, many > servers receiving mail spoofed for your domain will begin to drop it > rather > than backscatter emails back to your server. > > You should study the information on their site but in a nutshell, you > create > a TXT record in DNS that lists your servers IP as the only valid > machine to > send mail for your domain. This tells the others to drop emails from > other > IPs using your domain. It's relatively effective and painless. > Thank you That really did the trick.. Within two hours the flood of backscatter (about 400 an hour) was virtually gone That was great advice David
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