[ale] nslookup problems
ologgio at vrainn.com
Tue Oct 8 12:22:00 EDT 1996
Matthew Avery Writes :
:So as not to keep you all in the dark here is something new
:I discovered when playing with nslookup.
:Here are the results from several nslookup sessions I ran.
:It looks to me like the nameserver is working OK:
:>From miranda (Linux machine at my desk):
:miranda 38# nslookup - 184.108.40.206
:*** Can't find server name for address 220.127.116.11: No response from server
:*** Default servers are not available
:miranda 39# nslookup - 18.104.22.168
:Default Server: fs01.nas.nasa.gov
:For some reason I can't *start* nslookup with the default
:nameserver for miranda but if I start it with another
:nameserver and then switch it works fine. Very strange.
Actually this is the proper behaviour.
When you start nslookup with "- 22.214.171.124" the
a. 126.96.36.199 is added to the list of available name servers
b. A PTR query is sent to the list of available name servers to find the
FQDN for 188.8.131.52
c. 184.108.40.206 doesn't have a PTR record for itself. nslookup doesn't
have any more nameservers to use.
d. Terminates with an error saying it can't find the FQDN for 220.127.116.11
So, you are probably missing a PTR (IP adress to name mapping) record for
18.104.22.168...you need to add something like:
22.214.171.124.in-addr.arpa. IN PTR nameserver.asetech.com
Now you are probably asking yourself why does it work when you switch
to the server *after* starting nslookup with the other server.
The reason is that nslookup is a little bit more permissive when you already
have entered interactive mode (it doesn't require the PTR record for the
nameserver). I agree this is inconsistent, but this is useful when
Forgetting PTR records is one of the most common errors when setting up
nameservers. Usually they are not caught, unless people try to ftp to a
"smart" ftp server (like ftp.funet.fi) which double-checks and makes sure
the reverse-mapping (IP to name) matches the direct-mapping (name to IP).
Don't forget to contact interNic to register your reverse-address mapping if
you own your set of IP addresses.
Hmm....I take that back........judging by whois 126.96.36.199 looks like your
inverse mapping is provided by internal servers at NASA....you probably
don't need to contact InterNIC. Just make sure your inverse mapping is
registered in your master nameservers.
/ __ __ __ - __ __ / - _ __ ologgio at vrainn.com
Omar R. /__ /_/ /_/ /_/ / /_/ /_/ / /_ /-_ CIS: 74040,1543
Apple ]['s, remember Applesoft?
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