Curtis, As I stated in my previous e-mail, we could do this by adding this to our release notes in our product, describing the problem and advising against not taking measures. However, this would only apply to our customers, which I would venture to say that most already do understand the problem :). However, if there is anything that I can do to help, please let me know since I take the threat of the "imminent death of the internet" very seriously. Pat R. Calhoun e-mail: pcalhoun@usr.com Project Engineer - Lan Access R&D phone: (847) 933-5181 US Robotics Access Corp. ______________________________ Reply Separator _________________________________ Subject: Re: Re[2]: SYN floods (was: does history repeat itself?) Author: Curtis Villamizar <curtis@ans.net> at Internet Date: 9/12/96 1:44 PM In message <233128C0.3000@usr.com>, Pat Calhoun writes:

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Perry,

This is actually quite simple to implement on Dial Access Routers, and obviously this is the best place to add the filtering.

Pat R. Calhoun e-mail: pcalhoun@usr.com Project Engineer - Lan Access R&D phone: (847) 933-5181 US Robotics Access Corp.

I agree with you completely -- sort of. Only problem is there are thought to be some 3,000 dial access providers. Many of them barely know what a TCP SYN is, let alone why they need to block ones with random source addresses and how. Unless of course you are volunteering to explain it and help them. Thanks in advance. :-) Curtis

______________________________ Reply Separator ______________________________ ___ Subject: Re: SYN floods (was: does history repeat itself?) Author: "Perry E. Metzger" <perry@piermont.com> at Internet Date: 9/9/96 1:19 PM

Re: SYN floods

PANIX, a large public access provider in New York, was badly hit with SYN flood attacks from random source addresses over the last few days. It nearly wrecked them.

I think its time for the larger providers to start filtering packets coming from customers so that they only accept packets with the customer's network number on it.

Yes, its a load on routers. Yes, its nasty for the mobile IP weenies. Unfortunately, the only known way to stop this. Many TCPs go belly up as soon as they get SYN flooded -- its a defect in the protocol design, and other than Karn style anti-clogging tokens ("cookies") being put into a TCP++ and mass implemented worldwide soon, the only reasonable way to stop this sort of terrorism is provider filtering.

Perry --IMA.Boundary.388702248 Content-Type: text/plain; charset=US-ASCII; name="RFC822 message headers" Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part Content-Disposition: attachment; filename="RFC822 message headers"

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