North American Network Operators Group
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RE: DDOS attacks and Large ISPs doing NAT?

  • From: Ian Cooper
  • Date: Thu May 02 14:12:21 2002

--On Thursday, May 2, 2002 10:30 -0700 "Mansey, Jon" <[email protected]> wrote:

To merge these 2 great threads, it is the case is it not that NAT is a
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 phone with a 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?

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...)

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?

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.

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?