"Also while Deepak pointed out that you could perform line rate packet filtering only allowing packets to valid destinations on your network, this would only stop someone defaulting you but would not stop someone repointing next hop to valid destinations on your network." Besides politics, and QoS issues, is the latter scenario worth wasting management time on? I always thought that the biggest concern for most networks was a "peer" defaulting to you such that your interface would then forward the packet to its final destination [ostensibly a peer of yours at the same IX, but potentially across your network first]. I would think that if you did mac address exclusion [mac addresses of those you don't peer with] and ingress destination filtering a large percentage of the problem would vanish. Then again, if you are just doing mac address exclusion, it doesn't really keep someone from changing their mac address in software as often as they please. If you did inclusion filtering [only those on the allow list] then anytime someone swaps a card, you lose a peer. Hmmm. I guess that's the whole point of private cross connects. Deepak Jain AiNET -----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu]On Behalf Of David McGaugh Sent: Monday, February 11, 2002 3:15 PM To: Lane Patterson Cc: nanog@merit.edu Subject: Re: Ethernet EP - MAC Address Filtering I would be planning deploy it on the Juniper Platforms and it appears that at least the 4 port FE PICs support it as well. I would imagine (without actually investigating it) you could do some sort of port security on the 65xx/76xx platform though. Primarily I am questioning whether it would be scalable in the long term or whether it would become more trouble than what it would be worth. Also while Deepak pointed out that you could perform line rate packet filtering only allowing packets to valid destinations on your network, this would only stop someone defaulting you but would not stop someone repointing next hop to valid destinations on your network. -Dave Lane Patterson wrote:
I'm aware that Juniper GigE interfaces support a mac-filter-list. I'm not well versed on which versions of Cisco router products support this well (and line rate), but I didn't think GSRs and 7xxx had any support for this. Are the L2/L3 family (65xx, 76xx) able to handle mac-filters at line rate w/o a slow path?
I too would be interested in knowing if folks perform mac-filtering.
Certainly there are other measures you can take as well, such as scripting some default-pointing traceroute checks, to check both peers and non-peers on an IXP fabric. These have been documented at various times, and Avi at one point posted some form of this to Nanog (moons ago...search
archives).
My impression of "best practices" would be to:
1. implement mac-filter or mac-counters to prevent any illegally statically routed non-peer traffic. 2. implement traceroute scripts to check that peers are not defaulting any partial transit thru you.
Feedback welcome :-)
Cheers, -Lane
On Fri, Feb 08, 2002 at 10:29:07AM -0800, David McGaugh
<david_mcgaugh@eli.net> wrote:
Hello NANOG,
Just curious if anyone is performing MAC Address Filtering at any
of
the Ethernet Exchange Points. If so has it been found to be easy to administer or difficult where by peers may be changing Layer 3 devices or Interfaces without notice? Alternately is MAC Address Filtering considered an unneeded security measure?
Thanks, Dave Content-Description: Card for Dave McGaugh