Perhaps I should s/zombie/reflector in my orginal post. Jm

-----Original Message----- From: Ian Cooper [mailto:ian@the-coopers.org] Sent: Thursday, May 02, 2002 11:04 AM To: nanog@merit.edu Cc: Mansey, Jon Subject: RE: DDOS attacks and Large ISPs doing NAT?

--On Thursday, May 2, 2002 10:30 -0700 "Mansey, Jon" <Jon_Mansey@verestar.com> wrote:

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To merge these 2 great threads, it is the case is it not

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great way to avoid DDOS problems. I don't even want to imagine what the billing/credit issues would be like if your always-on

that NAT is a phone with a

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real IP is used as a zombie in a DDOS. "Hey I didn't use all that traffic last month....etc etc"

And NAT helps you stop zombie software being installed on the always-on device (phone) precisely how? What's to say that an infected system (or vandal's system) isn't going to be connected inside the NATed space?

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I still maintain, since the last time this was on Nanog, that real IP addresses should not be entrusted to the great unwashed.

The problem isn't that they're unwashed, the problem is that they're being pushed software that has bugs and holes that can be exploited (oh look, the "bash Microsoft" thread...)

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And as for NAT breaking applications, I think its time the applications wised up and worked around the NAT issues.

And what about those applications (protocols) that already exist and break when NAT exists? Or applications that simply don't scale well when NAT exists?

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Look, if your application is important enough to you as the developer, you are going to want it to penetrate and work for as many ppl as possible right? Office workers, home users with gateways, GPRS/GSM/3G cell users etc etc. So you make it use protocols that traverse NAT without breaking. Look at the streaming media players out there, they try to use, in order, multicast (the most effcient and best quality), UDP,TCP then HTTP. If it cant get a connection with any of the first protocols, it falls back to http, and you get your stream.

Right, and as you move toward HTTP you end up with a stream that becomes more and more expensive to deliver (and receive) and it frequently becomes harder and harder (and takes longer) to develop that application.

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When you look at the economics of usability of your app, I think your going to want to make it work through firewalls.

Depends where the firewall is being run as to whether you want it to break the application or not, but if it's possible for all great apps to run through firewalls how long is it going to be before "nasty" apps do that well?