Port Blocking - Proxy Mailers - GoFuckYourself.com

proximate · 01-22-2005, 07:47 AM

Those of you that have been reading our regular updates on "blocked/filtered" proxies, will recall we have thought for a long time the problem was an upstream software change.

The evidence is partly anecdotal, partly factual.

a) Linuxes & Winboxes are both being blocked, so it is not limited to O/S.

b) It affects Linux custom mailers, DM Win Mailers & some internal mailers.

c) Changing IP's WILL work on some networks, but NOT on others, so it is not limited to sub nets on IDC's.

The first reports of fully tested P's not working occured around 15th Dec, speading to most popular IDCs in late Dec thru' early Jan, and by around 10th Jan it had become endemic.

The pattern of gradual change first led us to believe it was a software update.

A close relationship with several IDC's who swore they were not filtering, but whose servers were being blocked, led us to conclude it was at router level.

We cannot say "WOW we have definitely solved it" but we think the answer lies with changes IBM & CISCO forecast would occur in late 2004 / early 2005.

IBM's alphaWorks have been working with CISCO on a new FairUCE spam filter for mail servers:

FairUCE (which stands for "Fair use of Unsolicited Commercial Email") is a spam filter that prevents spam from reaching the recipient's inbox by verifying the identity of the sender, in the case of proxies ... the IP.

It appears to work very similar to SPF, but much faster, as it does not check so many parameters.

There were several news items over the past 6 months that contain pieces of this jig-saw puzzle, but it looks increasingly likely CISCO may have made the backbone providers an offer they can hardly afford to refuse.

"If you buy our new updated FairUCE routers you will save thousands of $$$$ in wasted resouces."

The theory fits the facts, but I guess we won't know for sure until either IBM or Cisco "spill the beans".

For more information on the IBM / Cisco tie up read :

http://www.techworld.com/security/ne...fm?NewsID=2848

http://www.techworld.com/security/ne...fm?NewsID=1766

http://www.nwfusion.com/compendium/2004/006932.html

http://news.com.com/Stopping+spam+at...3-5316964.html

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01-22-2005, 07:47 AM	#1
proximate Registered User Join Date: Nov 2004 Posts: 60	Port Blocking - Proxy Mailers Those of you that have been reading our regular updates on "blocked/filtered" proxies, will recall we have thought for a long time the problem was an upstream software change. The evidence is partly anecdotal, partly factual. a) Linuxes & Winboxes are both being blocked, so it is not limited to O/S. b) It affects Linux custom mailers, DM Win Mailers & some internal mailers. c) Changing IP's WILL work on some networks, but NOT on others, so it is not limited to sub nets on IDC's. The first reports of fully tested P's not working occured around 15th Dec, speading to most popular IDCs in late Dec thru' early Jan, and by around 10th Jan it had become endemic. The pattern of gradual change first led us to believe it was a software update. A close relationship with several IDC's who swore they were not filtering, but whose servers were being blocked, led us to conclude it was at router level. We cannot say "WOW we have definitely solved it" but we think the answer lies with changes IBM & CISCO forecast would occur in late 2004 / early 2005. IBM's alphaWorks have been working with CISCO on a new FairUCE spam filter for mail servers: FairUCE (which stands for "Fair use of Unsolicited Commercial Email") is a spam filter that prevents spam from reaching the recipient's inbox by verifying the identity of the sender, in the case of proxies ... the IP. It appears to work very similar to SPF, but much faster, as it does not check so many parameters. There were several news items over the past 6 months that contain pieces of this jig-saw puzzle, but it looks increasingly likely CISCO may have made the backbone providers an offer they can hardly afford to refuse. "If you buy our new updated FairUCE routers you will save thousands of $$$$ in wasted resouces." The theory fits the facts, but I guess we won't know for sure until either IBM or Cisco "spill the beans". For more information on the IBM / Cisco tie up read : http://www.techworld.com/security/ne...fm?NewsID=2848 http://www.techworld.com/security/ne...fm?NewsID=1766 http://www.nwfusion.com/compendium/2004/006932.html http://news.com.com/Stopping+spam+at...3-5316964.html Bought to you by : "The professional service" "Money Back Guarantee" 2 Linux Botnets 8 Linux Scanners. 2 Linux Testers Free 2 hr trial ICQ : 267-157-438