Re: Rate limiting UDP,Multicast,ICMP

["Brian" <bri () sonicboom org>]

I have alao heard of providers who have rate limited icmp on their own
backbone links, or links facing peering partners, just something else to
consider..

        Brian

----- Original Message -----
From: "David Schwartz" <davids () webmaster com>
To: <TGainer () e-xpedient com>; <nanog () merit edu>
Sent: Wednesday, November 14, 2001 2:53 PM
Subject: Re: Rate limiting UDP,Multicast,ICMP


> On Tue, 13 Nov 2001 12:42:01 -0500, Thomas Gainer wrote:
>
> > A little more information.  We sell 100Mb Ethernet pipes to the Internet.
> > (Yes, there are a few of us left).  A fair number of these customers are
> > small businesses.  Usually, they have servers but very little IT support
and
> > even less IT know how.  My thought is to rate limit UDP and ICMP at the
> > customer port to no more than 3Mb/s so WHEN (not if) a customer is
> > compromised, the effects are somewhat limited and my MAN pipes have some
> > measure protection.  The question is, what am I not thinking of?  DNS,
TFTP
> > and such should all operate virtually unaffected, as they are not
bandwidth
> > hungry services.
>
> Are you rate limiting only inbound? Or both ways? Are you trying to
protect
> your customers from attack or prevent them from being the source of
attacks
> if their machines are compromised? Or both?
>
> If you rate-limit UDP outbound, you make it very hard for your customers
to
> source streaming media. If you rate-limit inbound, you make it very hard
for
> your customers to reflect streaming media. So long as you let your
customers
> know what you're doing in advance, you shouldn't have any problems.
>
> You may wish to allow clueful customers to opt out of this filtering
> (ideally selectively) if they do wish to do things with high-bandwidth UDP
> applications. It wouldn't be unreasonable to require customers opting out
of
> such filtering to assume responsibility/liability for any floods that
might
> affect them as a result. You may wish to charge them for your costs
associate
> with floods they originate that affect others as well.
>
> DS