SUMMARY: Lame servers

From: Stephen Harris (sweh@mpn.com)
Date: Tue Oct 15 1996 - 03:50:50 CDT


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Well, It's nice to know my servers aren't at fault :-)

I originally asked about the following entries in my log files, and what
they meant (and should I panic :-))

Oct 14 19:07:38 nebula named[105]: Lame server on 'dat.com' (in 'dat.com'?):
  [198.145.109.8].53 'ROGUE.dat.com': learnt (A=192.36.148.17,NS=192.36.148.17)
Oct 14 19:09:27 nebula named[105]: Lame server on 'ctronsoft.co.au' (in 'AU'?):
  [198.6.1.1].53 'NS.UU.NET': learnt (A=128.63.48.85,NS=128.63.2.53)
Oct 14 21:07:21 nebula named[105]: Lame server on 'fugue.com' (in 'fugue.com'?):
  [198.6.1.1].53 'NS.UU.NET': learnt (A=128.63.48.85,NS=192.36.148.17)

Answer:
  it's not my fault :-)

The TCP-IP/Domains FAQ (internet/tcp-ip/domains-faq/part1) has some information
on this. A copy of the May 95 (old...?) version is available at
http://www.shmooze.net/~infopit/faqs/tcpip.txt - check out section 3.5
(but 3.3 is relevant as well.

Basically a lame delegation is one where the domain hierarchy above (eg
COM) servers have NS records pointing to a machine (ie a delegation) but
that machine doesn't respond with an "authorative" answer.
eg if I ask for the NS records for "mr-fundsdirect.com."

  % nslookup -type=ns mr-fundsdirect.com.
  Server: localhost
  Address: 127.0.0.1

  Non-authoritative answer:
  mr-fundsdirect.com nameserver = NS3.CHINA.COM
  mr-fundsdirect.com nameserver = NS1.CHINA.COM

  Authoritative answers can be found from:
  NS3.CHINA.COM internet address = 202.84.1.103
  NS1.CHINA.COM internet address = 202.84.1.101
  
But if I ask NS3.CHINA.COM the same question, the answer does not come back
authorative:

  % nslookup -type=ns mr-fundsdirect.com. ns3.china.com
  Server: china.com
  Address: 202.84.1.103

  Non-authoritative answer:
  mr-fundsdirect.com nameserver = NS1.CHINA.COM
  mr-fundsdirect.com nameserver = NS3.CHINA.COM

  Authoritative answers can be found from:
  MR-FundsDirect.com nameserver = NS1.CHINA.COM
  MR-FundsDirect.com nameserver = NS3.CHINA.COM
  NS1.CHINA.COM internet address = 202.84.1.101
  NS3.CHINA.COM internet address = 202.84.1.103

So the delegation to NS3.CHINA.COM is "Lame".

How can Lame delegations come about? A number of ways:
  1) the designated server doesn't have a "primary" or "secondary" line in
     the named.boot file
  2) the Zone file has a parse error
  3) Zone transfer from primary fails (Bill Townsley: is this your problem
            with rogue? It seems to be responding authorative now!)

Ugh, there are a LOT of Lame servers out there...:-(

Thanks to:
  Gokhan Ozkan
  Rachel Polanskis
  Raju Krishnamurthy
  David Schiffrin
  Reto Lichtensteiger

rgds
Stephen

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