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Re: Strange announcements

  • From: Danny McPherson
  • Date: Thu Feb 10 11:15:32 2000


This was resultant of some left over garbage from a deomonstration I was
planning to perform during the route filtering panel Tuesday morning, I
had forgot about it (JUST KIDDING!!!).

It's obvious that it was the result of a configuration error and it's
long since been corrected.  Fortunately, it didn't [completely] break
anything.

It does, however, serve as a nice follow-on to my comments regarding
providers needing the ability to perform prefix-based filtering on a
per-peer level in addition to the current "just BGP customer routes are
filtered".  Filtering of this level would require vendors to support
hundreds of thousands of lines of ingress prefix-based filtering
policies, something that's not __completely available today.

Presumably, this same set of policies could also be used to perform
unicast RPF-type functions WRT SA-based packet filtering.  This would
scope the effects of IP spoofing considerably, and remove some of the
vulnerabilities regarding unauthenticated origination of BGP routes.

A widely-deployed explicit acceptence model (prefix filtering) would
also allow providers (who are concerned with de-aggregation and the like
hosing their routers) to remove prefix-length based policies, and Save
all the "rural" multi-homed folks.

Of course, this also assumes that scalable backend infrastructure and
systems are in place to authenticate database object entries, etc..

Then again, an SS7-type solution with backend databases and an
out-of-band network populating SCPs, along with a completely static
transport system, provides support for number portability, perhaps we're
simply overlooking something?

-danny




[snip]
To QWEST NOC PEOPLE

Folks,
You appear to be announcing 198.133.219.0, which is the
network that www.cisco.com lives on, whats strange is that
you are then transiting this route onto GTEI [AS1] to deliver
the traffic. This is fairly sub-optimal and I'm sure incorrect.

kenny>sh ip bgp 198.133.219.25
BGP routing table entry for 198.133.219.0/24, version 23258497
Paths: (4 available, best #1, advertised over IBGP)
  3356 209
    209.244.160.57 from 209.244.160.57 (209.244.2.210)
      Origin IGP, metric 4401, localpref 100, valid, external, best
  3356 209, (received-only)
    209.244.160.57 from 209.244.160.57 (209.244.2.210)
      Origin IGP, metric 4401, localpref 100, valid, external
  1 109
    4.1.74.105 from 4.1.74.105 (4.0.4.8)
      Origin IGP, metric 11340, localpref 100, valid, external
      Dampinfo: penalty 492, flapped 1 times in 00:00:23
  1 109, (received-only)
    4.1.74.105 from 4.1.74.105 (4.0.4.8)
      Origin IGP, metric 11340, localpref 100, valid, external

kenny>traceroute www.cisco.com

Type escape sequence to abort.
Tracing the route to www.cisco.com (198.133.219.25)

  1 serial4-0-3.hsa1.nyc1.Level3.net (209.244.160.57) [AS 3356] 0 msec 0
msec 0 msec
  2 hsipaccess2.Denver1.Level3.net (209.244.2.61) [AS 3356] 48 msec 48
msec 48 msec
  3 hsipaccess2.Seattle1.Level3.net (209.244.2.23) [AS 3356] 76 msec 72
msec 76 msec
  4 209.0.227.130 [AS 3356] 76 msec 200 msec 148 msec
  5 sea-core-01.inet.qwest.net (205.171.26.53) [AS 209] 76 msec 72 msec
76 msec
  6 sfo-core-02.inet.qwest.net (205.171.5.105) [AS 209] 84 msec 84 msec
84 msec
  7 sjo-core-01.inet.qwest.net (205.171.5.121) [AS 209] 80 msec 80 msec
80 msec
  8 sjo-edge-05.inet.qwest.net (205.171.22.46) [AS 209] 84 msec 84 msec
80 msec
  9 a5-0-1.sanjose1-nbr1.bbnplanet.net (4.24.145.1) [AS 1] 84 msec 84
msec 84 msec
 10 p4-0.paloalto-nbr2.bbnplanet.net (4.0.1.1) [AS 1] 84 msec 84 msec 84
msec
 11 p0-0-0.paloalto-cr18.bbnplanet.net (4.0.3.86) [AS 1] 84 msec 84 msec
84 msec
 12  *  *  *
 13 pigpen.cisco.com (192.31.7.9) [AS 109] 88 msec 88 msec 88 msec
 14 www.cisco.com (198.133.219.25) [AS 209] 88 msec 84 msec 88 msec

A fix/explanation would be useful.

Regards,
Neil.
--
Neil J. McRae                                C O L T  I N T E R N E T
neil@COLT.NET





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