problems with 192.168 address space

From Mon Aug 2 17:30:06 2004
Date: Mon, 02 Aug 2004 18:25:00 -0400
From: Eric Kimminau <>
Subject: problems with 192.168 address space


Anyone having problems with and 192.168 public broadcasts?

Covad uses some RFC-1918 space internally, for routers, etc. Nothing
unusual there.

They are known to use the low part of the space for the
PPP links betwen CPE and DSLAM, and the high part of the same space
for the 'upstream gateway'.

They use for internal routing.

They do not use 'Net 10' _at_all_.

A traceroute from my home network goes from my dsl modem/router to a
172.31.x.x address; then through two 192.168.x.x addresses, And then
to the public internet.

Covad does NOT filter *any* RFC-1918 _source_address_ packets from going
_to_ their customers.

I've had some lengthy discussions with their abuse desk about this, when
my firewall has blocked/logged hostile *incoming* packets with RFC-1918
source addresses.

For "some strange reason" they can't tell, _or_track_, where those packets
are coming from.

I'm told they _do_ have RFC-1918 ingress and egress filtering for both source
and destination addresses, at their gateways to the _external_ internet. That
-that- filtering means that the stuff that shows up 'at _my_ front door' *is*
coming from another COVAD customer, and not from "somewhere _outside_ Covad's