Subject: RE: Removing features

From: "Michel Py" <[email-masked]>
Date: Tue, 14 Oct 2003 08:05:56 -0700

Kurtis,

>> Michel Py wrote:
>> - Do not flood root servers with reverse lookup queries for
>> private addresses (I want my traceroutes to work on the
>> inside of the network too, so I long ago configured reverse
>> lookup for private addresses on my internal DNS servers).

> Kurt Erik Lindqvist wrote:
> Say again?

Where are all these bogus requests to reverse lookup an RFC1918 address
coming from? From hosts with a RFC1918 address that do a traceroute.
Even if the target of the traceroute is outside, the first hop is
inevitably inside. The traceroute does a reverse lookup on each hop for
display purposes; this reverse lookup fails on the local DNS server and
might end up in one of the roots.

However, if a reverse lookup zone (1.168.192.in-addr.arpa in this case)
is configured in the DNS server that the host doing the traceroute is
using, and if the correct PTR is configured (1.1.168.192.in-addr.arpa
PTR cisco.arneill-py.sacrament.ca.us) the traceroute correctly
reverse-lookups the first hop and that request never ends up in a root
server. Also, it's faster because it does not waste 5 seconds timing out
on the request.

tracert www.ietf.org
  1     1 ms     1 ms     1 ms  cisco.arneill-py.sacrament.ca.us
[192.168.1.1]
  2    12 ms    12 ms    61 ms
adsl-209-233-126-254.dsl.scrm01.pacbell.net [209.233.126.254]

Michel.

---

From: Kurt Erik Lindqvist <[email-masked]>
Date: Wed, 15 Oct 2003 07:26:10 +0200

> coming from?

There are a hell of a lot traceroutes going on then...

Also note that at least at i.root there are a lot  more queries with 
src addresses being RFC1918. This is the same for f.root as far as I 
can remember.

> might end up in one of the roots.

Well, as for the reverse lookup it should end up with one of the AS112 
servers as the in-addr.arpa zones have been delegated.

> server. Also, it's faster because it does not waste 5 seconds timing 

I won't argue against you. Now, why don't people do this?

- - kurtis -