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I need help resolving a dns issue. One of my websites, kengraycoaching.com, suddenly became unavailable and returns a 404 not found error. It had been working fine until yesterday. Is it my hosting provider (shared hosting) or my ISP?

The hosting provider says "It's nothing on our network and it appears your ISP's DNS server isn't grabbing the zone from us."

The DNS servers for kengraycoaching.com are set to 56a.genwebserver.net and 56b.genwebserver.net. I have other sites on the same shared hosting server that work fine.

nslookup returns a SRVFAIL. I tried several dig commands, but I don't really know how to interpret the results or how to fix the issue. Here's what I've tried:

:~ steve$ nslookup kengraycoaching.com

Server: 192.168.1.1
Address:    192.168.1.1#53

** server can't find kengraycoaching.com: SERVFAIL


:~ steve$ dig kengraycoaching.com

; <<>> DiG 9.6.0-APPLE-P2 <<>> kengraycoaching.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 42660
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;kengraycoaching.com.       IN  A

;; Query time: 168 msec
;; SERVER: 192.168.1.1#53(192.168.1.1)
;; WHEN: Tue Apr 26 09:42:03 2011
;; MSG SIZE  rcvd: 37


:~ steve$ dig +trace kengraycoaching.com

; <<>> DiG 9.6.0-APPLE-P2 <<>> +trace kengraycoaching.com
;; global options: +cmd
.           92895   IN  NS  c.root-servers.net.
.           92895   IN  NS  d.root-servers.net.
.           92895   IN  NS  b.root-servers.net.
.           92895   IN  NS  m.root-servers.net.
.           92895   IN  NS  h.root-servers.net.
.           92895   IN  NS  k.root-servers.net.
.           92895   IN  NS  l.root-servers.net.
.           92895   IN  NS  e.root-servers.net.
.           92895   IN  NS  f.root-servers.net.
.           92895   IN  NS  a.root-servers.net.
.           92895   IN  NS  g.root-servers.net.
.           92895   IN  NS  j.root-servers.net.
.           92895   IN  NS  i.root-servers.net.
;; Received 472 bytes from 192.168.1.1#53(192.168.1.1) in 18 ms

com.            172800  IN  NS  h.gtld-servers.net.
com.            172800  IN  NS  m.gtld-servers.net.
com.            172800  IN  NS  k.gtld-servers.net.
com.            172800  IN  NS  j.gtld-servers.net.
com.            172800  IN  NS  f.gtld-servers.net.
com.            172800  IN  NS  d.gtld-servers.net.
com.            172800  IN  NS  g.gtld-servers.net.
com.            172800  IN  NS  e.gtld-servers.net.
com.            172800  IN  NS  l.gtld-servers.net.
com.            172800  IN  NS  b.gtld-servers.net.
com.            172800  IN  NS  c.gtld-servers.net.
com.            172800  IN  NS  a.gtld-servers.net.
com.            172800  IN  NS  i.gtld-servers.net.
;; Received 497 bytes from 202.12.27.33#53(m.root-servers.net) in 136 ms

kengraycoaching.com.    172800  IN  NS  56a.genwebserver.net.
kengraycoaching.com.    172800  IN  NS  56b.genwebserver.net.
;; Received 121 bytes from 192.5.6.30#53(a.gtld-servers.net) in 134 ms

kengraycoaching.com.    14400   IN  A   64.27.53.90
kengraycoaching.com.    86400   IN  NS  56a.genwebserver.net.
kengraycoaching.com.    86400   IN  NS  56b.genwebserver.net.
;; Received 105 bytes from 64.27.53.90#53(56a.genwebserver.net) in 46 ms



:~ steve$ dig kengraycoaching.com @h.gtld-servers.net

; <<>> DiG 9.6.0-APPLE-P2 <<>> kengraycoaching.com @h.gtld-servers.net
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 28748
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 2
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;kengraycoaching.com.       IN  A

;; AUTHORITY SECTION:
kengraycoaching.com.    172800  IN  NS  56a.genwebserver.net.
kengraycoaching.com.    172800  IN  NS  56b.genwebserver.net.

;; ADDITIONAL SECTION:
56a.genwebserver.net.   172800  IN  A   64.27.53.90
56b.genwebserver.net.   172800  IN  A   64.27.53.91

;; Query time: 190 msec
;; SERVER: 192.54.112.30#53(192.54.112.30)
;; WHEN: Tue Apr 26 09:48:36 2011
;; MSG SIZE  rcvd: 121

:~ steve$ dig @56a.genwebserver.net kengraycoaching.com

; <<>> DiG 9.6.0-APPLE-P2 <<>> @56a.genwebserver.net kengraycoaching.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 26117
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 0
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;kengraycoaching.com.       IN  A

;; ANSWER SECTION:
kengraycoaching.com.    14400   IN  A   64.27.53.90

;; AUTHORITY SECTION:
kengraycoaching.com.    86400   IN  NS  56a.genwebserver.net.
kengraycoaching.com.    86400   IN  NS  56b.genwebserver.net.

;; Query time: 46 msec
;; SERVER: 64.27.53.90#53(64.27.53.90)
;; WHEN: Tue Apr 26 11:17:49 2011
;; MSG SIZE  rcvd: 105

I'd appreciate help in debugging this. Thanks.

[edit: added results of :~ steve$ dig @56a.genwebserver.net kengraycoaching.com for more info.]

share|improve this question
    
I was half way into an answer when I tested it myself. I can actually reach the site in question and your DNS servers are returning a valid A record for kengraycoaching.com. Can you run dig @56a.genwebserver.net kengraycoaching.com and add that to your question? –  SmallClanger Apr 26 '11 at 17:29
    
[WORKSFORME] (both 56a and 566b are returning valid responses for your domain - I see no SERVFAIL here :)) –  voretaq7 Apr 26 '11 at 17:37
    
It does look like it's a lack of communication between your ISP's DNS and your site host's DNS. I'm used to SERVFAIL being associated with invalid DNSSEC information -- could that be involved? –  bgvaughan Apr 26 '11 at 17:56
    
Thanks for the help everyone. It's working now. Presumably an issue with the ISP. –  LandedGently Apr 26 '11 at 18:44

1 Answer 1

up vote 1 down vote accepted

The +trace version steps through the process of "recursion" and shows that it works properly when it's done step-by-step. The steps of recursion here are:

  1. A root server is chosen from the built-in list of root servers.
  2. m.root-servers.net says *.gtld-servers.net runs .com
  3. a.gtld-servers.net says 56a/b.genwebserver.net runs kengraycoaching.com
  4. 56a.genwebserver.net says the IP address for "kengraycoaching.com" is "64.27.53.90"

As an aside, dig [A] www.somehostname.com @*.gtld-servers.net is generally never going to give a meaningful answer, the purpose of these servers are to point people to the nameservers you registered for your .com domain.

From what you've got so far, I would say that the nameserver on 192.168.1.1 (a cable/dsl router, I presume?) is misconfigured or otherwise broken. If the configuration has an IP address (your ISP's DNS server, presumably) that the router is using, try dig hostname @tha.tad.dre.ss to force dig to skip 192.168.1.1 and talk to that DNS server directly. If it works, then something is wrong with the router. If there's no response, then the either the ISPs DNS server is down or you have the wrong address. If talking to the server directly works but won't resolve the address, then there's a problem with the ISP's DNS server.

share|improve this answer
    
It's working now. Yes, 192.168.1.1 is my dsl router. It is set up to get DNS addresses automatically, so I think it was a problem with my ISP. @DerfK, thanks for explaining how the +trace option works for dig. –  LandedGently Apr 26 '11 at 18:43

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