[lug] DNS Problems: Is it me, or is it Comcast?

[Michael Deck]

At 11:40 AM 10/4/2004, David Anselmi wrote:

>Michael Deck wrote:
>[...]
>
>Apparently your home office DNS cache is broken.  Your name server
>(198.49.126.122) is working fine (as indicated by others' replies).

David, I'm not sure where the cache is located. Just to explain, my "home 
office" is a Linux box behind a router behind a cable box. I don't *think* 
that Linux box is caching DNS but if it is, how would I clear it?

Also, it's appearing that anyone who is on a Comcast.net system cannot get 
to me by name, but the rest of the world can.


>You can also use dig +trace cleansoft.com. to verify that your
>delegations are right and get you what you expect.

It looks ok to me (attached).


>The place to look then isn't on the cleansoft.com NS so forget about its
>zone files and BIND config (which you say you didn't change anyway).
>You need to look at your local resolv.conf and the name servers listed
>there.

If I put my own name server in /etc/resolv.conf it works fine, so I think 
the problem is with Comcast's name server.

>Do you understand the difference between a name server resolving names
>for clients (a DNS cache, using recursive queries) and a name server
>resolving names for other name servers (an authoritative name server,
>using non-recursive queries)?

I think so.

>HTH, apologies if I'm confusing, there seems to be a lack of consistent
>terminology when talking about DNS.  But I'll clarify if I can.


  dig +trace cleansoft.com

; <<>> DiG 9.2.2-P3 <<>> +trace cleansoft.com
;; global options:  printcmd
.                       97038   IN      NS      D.ROOT-SERVERS.NET.
.                       97038   IN      NS      E.ROOT-SERVERS.NET.
.                       97038   IN      NS      F.ROOT-SERVERS.NET.
.                       97038   IN      NS      G.ROOT-SERVERS.NET.
.                       97038   IN      NS      H.ROOT-SERVERS.NET.
.                       97038   IN      NS      I.ROOT-SERVERS.NET.
.                       97038   IN      NS      J.ROOT-SERVERS.NET.
.                       97038   IN      NS      K.ROOT-SERVERS.NET.
.                       97038   IN      NS      L.ROOT-SERVERS.NET.
.                       97038   IN      NS      M.ROOT-SERVERS.NET.
.                       97038   IN      NS      A.ROOT-SERVERS.NET.
.                       97038   IN      NS      B.ROOT-SERVERS.NET.
.                       97038   IN      NS      C.ROOT-SERVERS.NET.
;; Received 436 bytes from 204.127.202.4#53(204.127.202.4) in 62 ms

com.                    172800  IN      NS      A.GTLD-SERVERS.NET.
com.                    172800  IN      NS      B.GTLD-SERVERS.NET.
com.                    172800  IN      NS      C.GTLD-SERVERS.NET.
com.                    172800  IN      NS      D.GTLD-SERVERS.NET.
com.                    172800  IN      NS      E.GTLD-SERVERS.NET.
com.                    172800  IN      NS      F.GTLD-SERVERS.NET.
com.                    172800  IN      NS      G.GTLD-SERVERS.NET.
com.                    172800  IN      NS      H.GTLD-SERVERS.NET.
com.                    172800  IN      NS      I.GTLD-SERVERS.NET.
com.                    172800  IN      NS      J.GTLD-SERVERS.NET.
com.                    172800  IN      NS      K.GTLD-SERVERS.NET.
com.                    172800  IN      NS      L.GTLD-SERVERS.NET.
com.                    172800  IN      NS      M.GTLD-SERVERS.NET.
;; Received 463 bytes from 128.8.10.90#53(D.ROOT-SERVERS.NET) in 85 ms

cleansoft.com.          172800  IN      NS      ns1.cleansoft.net.
cleansoft.com.          172800  IN      NS      ns2.cleansoft.net.
;; Received 112 bytes from 192.5.6.30#53(A.GTLD-SERVERS.NET) in 62 ms

cleansoft.com.          86400   IN      A       198.49.126.122
cleansoft.com.          86400   IN      NS      ns2.cleansoft.net.
cleansoft.com.          86400   IN      NS      ns1.cleansoft.net.
;; Received 128 bytes from 198.49.126.122#53(ns1.cleansoft.net) in 416 ms

[deckm at themule deckm]$ dig cleansoft.com

; <<>> DiG 9.2.2-P3 <<>> cleansoft.com
;; global options:  printcmd
;; connection timed out; no servers could be reached
[deckm at themule deckm]$




Michael Deck
Cleanroom Software Engineering, Inc.