Weird nslookup problem (from O'Reilly book, page 84)
Chris
I'm setting up DNS on my little network here. Well actually I've had
it going for about a month, but I didn't really know what I was doing,
so I've bought the O'Reilly book and am going through it. I've gotten
to the part called 'Testing my Setup' (pages 82-84). Everything is
fine, until I get to 'One more test', in which I use another name
server to look up my hosts. Neat trick! I was calling friends to try
and ping me. Trouble is, I flunked, and I don't know why.
What I'm trying to find is www.tourneyland.net. My default domain is
tourneyland.net, and nslookup www works fine. nslookup
www.tourneyland.net gatekeeper.dec.com fails though, as does nslookup
www.tourneyland.net 151.164.1.8 (that's my ISP's name server). What's
strange is that doing the same nslookups with mail.tourneyland.net, or
other hosts works fine. Only www fails.
To summarize . . .
Bad:
nslookup www.tourneyland.net gatekeeper.dec.com
nslookup www.tourneyland.net 151.164.1.8
Good:
nslookup mail.tourneyland.net gatekeeper.dec.com
nslookup mail.tourneyland.net 151.164.1.8
nslookup ftp.tourneyland.net 151.164.1.8
And so forth. I've cut-n-pasted my RR file at the bottom. As you can
see, www, mail, and ftp are equivalent, so why they're acting
differently is beyond me. What am I missing?
Thanks,
Chris
@ IN SOA hoss.tourneyland.net. root.tourneyland.net.
(
199909283 ;
8H ;
2H ;
1W ;
1D) ;
TXT "Welcome To TourneyLand!!!"
NS hoss ;
NS bessie ;
MX 10 mail;
;
; localhost
localhost A 127.0.0.1
; network (I don't know why this is here)
tourneyland.net. A 216.62.177.0
MX 10 mail
; Everyone's name and IP address
momma A 216.62.177.1
MX 10 mail
hoss A 216.62.177.2
bessie A 216.62.177.3
MX 10 mail
lurch A 216.62.177.4
MX 10 mail
dumbass A 216.62.177.5
MX 10 mail
; Aliases
www CNAME hoss
ftp CNAME hoss
mail CNAME hoss
ns1 A 216.62.177.2
ns2 A 216.62.177.3
Barry Margolin
Chris <ch...@tourneyland.com> wrote:
>What I'm trying to find is www.tourneyland.net. My default domain is
>tourneyland.net, and nslookup www works fine. nslookup
>www.tourneyland.net gatekeeper.dec.com fails though, as does nslookup
>www.tourneyland.net 151.164.1.8 (that's my ISP's name server). What's
>strange is that doing the same nslookups with mail.tourneyland.net, or
>other hosts works fine. Only www fails.
gatekeeper.dec.com has an incorrect CNAME record cached:
www.tourneyland.net. 813 CNAME hossie.tourneyland.net.
You would have seen this if you used "dig" rather than the inferior
"nslookup" in your troubleshooting. That record should time out in about
10 minutes.
I tried your ISP's server and it worked OK. I also got the correct answer
with my local server.
However, I noticed that the domain I see when I query your server is not
quite the same as what you posted. Your actual SOA record has serial
number 1, but you posted serial number 199909283. Your secondary server,
bessie, is down at the moment. It's possible that the bad CNAME record was
coming from it; if you changed your serial number from 199909283 to 1,
bessie would not have done a zone transfer (zone transfers happen only when
the serial number increases).
--
Barry Margolin, bar...@bbnplanet.com
GTE Internetworking, Powered by BBN, Burlington, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.
Chris
>
>www.tourneyland.net. 813 CNAME hossie.tourneyland.net.
>
>You would have seen this if you used "dig" rather than the inferior
>"nslookup" in your troubleshooting. That record should time out in about
>10 minutes.
Thinking back, I think I did try www, at gatekeeper, and when it
failed (because it had hossie instead of hoss, I corrected my RR file,
but www still failed. A caching of a incorrect record would explain
why www failed but the equivalent ftp and mail (which I didn't look
for until I made the corrections) succeeded. I'll also look into dig -
it appears my system has it, so I'll figure out how to use it instead
of nslookup.
>I tried your ISP's server and it worked OK. I also got the correct answer
>with my local server.
>
>However, I noticed that the domain I see when I query your server is not
>quite the same as what you posted. Your actual SOA record has serial
>number 1, but you posted serial number 199909283. Your secondary server,
>bessie, is down at the moment. It's possible that the bad CNAME record was
>coming from it; if you changed your serial number from 199909283 to 1,
>bessie would not have done a zone transfer (zone transfers happen only when
>the serial number increases).
I switched serial number schemes when I saw that the D&B bok was using
1, 2, 3 instead of a date-revision number quasi-hash, and I liked the
simple scheme better. I know I switched from a big number to a small
number, but since I don't actually have a secondary server running
(there have been some hardware delays), I don't think anything has
loaded that big serial number, so I'm assuming it won't be a problem.
Thanks Barry,
Chris