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Intermittent access to website


CNAME to another domain fails on some office networks, why?CentOS BIND DNS Troubleshooting?DNS setup with BINDGlobal Reverse DNS look-ups not workingWindows 2008 dns server can't find his own host nameIntermittent DNS timeoutHow to determine where an IP returned by NSLOOKUP is coming fromUbuntu uses external DNS to resolve localhostDNS lookup takes 10 plus secondsServer 2012R2 DNS server returning SERVFAIL for some AAAA queries













2















Environment:




  • Active Directory domain with a single domain controller (Windows Server 2003 R2
    Standard x64 Edition - Service Pack 2) which is also the DNS


  • Windows XP Service Pack 3 clients. The client computers have ONLY our internal
    DNS server as their DNS address.



Our users have reported that occasionally they cannot visit Southwest Airlines
website www.southwest.com.



After a few days of trying we were able to reproduce the problem in a test user's
login.



When attempting to access the site in Firefox, the status bar says, "Looking up
www.southwest.com" and after a few moments Firefox displays:



Address Not Found



Firefox can't find the server at www.southwest.com



Similar results in Internet Explorer



We tried restarting the browser and the computer, but we still cannot access the
site. Other websites we tested work normally.



We tried accessing the website from another computer and got the same results.



nslookup reveals the following:



C:Documents and SettingsTestQ>nslookup www.teamdesk.net
Server: server.domain.local
Address: 172.21.31.206

Name: www.teamdesk.net
Address: 208.100.33.78


C:Documents and SettingsTestQ>nslookup www.southwest.com
Server: server.domain.local
Address: 172.21.31.206

DNS request timed out.
timeout was 2 seconds.
*** Request to server.domain.local timed-out


C:Documents and SettingsTestQ>nslookup
Default Server: server.domain.local
Address: 172.21.31.206

> www.southwest.com
Server: server.domain.local
Address: 172.21.31.206

DNS request timed out.
timeout was 2 seconds.
*** Request to server.domain.local timed-out

> set d2
> www.southwest.com
Server: server.domain.local
Address: 172.21.31.206

------------
SendRequest(), len 51
HEADER:
opcode = QUERY, id = 4, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
www.southwest.com.domain.local, type = A, class = IN

------------
------------
Got answer (119 bytes):
HEADER:
opcode = QUERY, id = 4, rcode = NXDOMAIN
header flags: response, auth. answer, want recursion, recursion avail.
questions = 1, answers = 0, authority records = 1, additional = 0

QUESTIONS:
www.southwest.com.domain.local, type = A, class = IN
AUTHORITY RECORDS:
-> domain.local
type = SOA, class = IN, dlen = 41
ttl = 3600 (1 hour)
primary name server = server.domain.local
responsible mail addr = hostmaster
serial = 2064
refresh = 900 (15 mins)
retry = 600 (10 mins)
expire = 86400 (1 day)
default TTL = 3600 (1 hour)

------------
------------
SendRequest(), len 35
HEADER:
opcode = QUERY, id = 5, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
www.southwest.com, type = A, class = IN

------------
DNS request timed out.
timeout was 2 seconds.
timeout (2 secs)
SendRequest failed
*** Request to server.domain.local timed-out


> www.google.com
Server: server.domain.local
Address: 172.21.31.206

------------
SendRequest(), len 48
HEADER:
opcode = QUERY, id = 6, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
www.google.com.domain.local, type = A, class = IN

------------
------------
Got answer (116 bytes):
HEADER:
opcode = QUERY, id = 6, rcode = NXDOMAIN
header flags: response, auth. answer, want recursion, recursion avail.
questions = 1, answers = 0, authority records = 1, additional = 0

QUESTIONS:
www.google.com.domain.local, type = A, class = IN
AUTHORITY RECORDS:
-> domain.local
type = SOA, class = IN, dlen = 41
ttl = 3600 (1 hour)
primary name server = server.domain.local
responsible mail addr = hostmaster
serial = 2064
refresh = 900 (15 mins)
retry = 600 (10 mins)
expire = 86400 (1 day)
default TTL = 3600 (1 hour)

------------
------------
SendRequest(), len 32
HEADER:
opcode = QUERY, id = 7, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
www.google.com, type = A, class = IN

------------
------------
Got answer (132 bytes):
HEADER:
opcode = QUERY, id = 7, rcode = NOERROR
header flags: response, want recursion, recursion avail.
questions = 1, answers = 6, authority records = 0, additional = 0

QUESTIONS:
www.google.com, type = A, class = IN
ANSWERS:
-> www.google.com
type = CNAME, class = IN, dlen = 8
canonical name = www.l.google.com
ttl = 69859 (19 hours 24 mins 19 secs)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.19
ttl = 300 (5 mins)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.20
ttl = 300 (5 mins)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.18
ttl = 300 (5 mins)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.17
ttl = 300 (5 mins)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.16
ttl = 300 (5 mins)

------------
Non-authoritative answer:
Name: www.l.google.com
Addresses: 74.125.239.19, 74.125.239.20, 74.125.239.18, 74.125.239.17
74.125.239.16
Aliases: www.google.com


How do we further diagnose and resolve this problem?



EDIT



I work with Brad. Thanks for your help so far.



1) The DNS server acts as the resolver. There is no forward lookup other than the root servers via root hints.



2) Under the error state (i.e., when the southwest.com lookups are timing out), nslookup southwest.com ns-1.southwest.com times out looking up the ns-1.southwest.com server. Same thing with ns-2.southwest.com.



3) Under the error state, nslookup southwest.com 12.5.136.190 and nslookup southwest.com 63.169.44.190 (i.e., against the IP addresses of ns-1 and ns-2.southwest.com) both work, returning southwest.com's IP addresses.



4) Under the error state, the cache is unchanged from when things are working normally. That is, dnsmgmtcached lookups.(root)comsouthwest always shows the following (including the A record for ns-2, which fails (see #2 above)).



Name                        Type                Data
---- ---- ----
(same as parent folder) Name Server (NS) ns-1.southwest.com
(same as parent folder) Name Server (NS) ns-2.southwest.com
(same as parent folder) Host (A) 208.94.152.100
(same as parent folder) Host (A) 208.94.153.100
ns-2 Host (A) 63.169.44.190


I suspect we're overlooking something obvious ...



EDIT



(Sorry for the delay. I posted this over 8 hours ago but it never appeared.)



Under the error state,



5) nslookup southwest.com against all *.gtld-servers.net servers succeeded



... QUESTIONS:
southwest.com, type = A, class = IN
AUTHORITY RECORDS:
-> southwest.com
type = NS, class = IN, dlen = 7
nameserver = ns-1.southwest.com
ttl = 172800 (2 days)
-> southwest.com
type = NS, class = IN, dlen = 7
nameserver = ns-2.southwest.com
ttl = 172800 (2 days)
ADDITIONAL RECORDS:
-> ns-1.southwest.com
type = A, class = IN, dlen = 4
internet address = 12.5.136.190
ttl = 172800 (2 days)
-> ns-2.southwest.com
type = A, class = IN, dlen = 4
internet address = 63.169.44.190
ttl = 172800 (2 days)

------------
Name: southwest.com
Served by:
- ns-1.southwest.com
12.5.136.190
southwest.com
- ns-2.southwest.com
63.169.44.190
southwest.com


6) nslookup southwest.com 208.67.222.222 (OpenDNS) succeeded



7) Clearing the cache fixed the problem, but it just returns later.



8) After clearing the cache and doing nslookup southwest.com (which succeeds), the cache now has ns-1's A record (it didn't under the error state, see #4 above)



Name                        Type                Data
---- ---- ----
(same as parent folder) Name Server (NS) ns-1.southwest.com
(same as parent folder) Name Server (NS) ns-2.southwest.com
(same as parent folder) Host (A) 208.94.153.100
(same as parent folder) Host (A) 208.94.152.100
ns-1 Host (A) 12.5.136.190
ns-2 Host (A) 63.169.44.190


9) Note that the DNS server only forwards to the root servers. Can you think of any reason that should cause this problem?










share|improve this question
















bumped to the homepage by Community 5 hours ago


This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
















  • maybe from your DNS server, try nslookup www.southwest.com ns-1.southwest.com and nslookup www.southwest.com ns-2.southwest.com This will show if your DNS server can access their DNS servers.

    – Sandman4
    Nov 6 '11 at 19:00











  • btw, your DNS server - how it configured - it acts as resolver or it merely forwards requests to your ISP ? - in the latter case, try nslookup www.southwest.com nsX.yourisp.net

    – Sandman4
    Nov 6 '11 at 19:03











  • Also, the L root IP is current.

    – user100178
    Nov 7 '11 at 3:55











  • Since the problems is looking-up nameservers names, now, you may try nslookup southwest.com a.gtld-servers.net ... m.gtld-serves.net. See if all requests answered and return both NS and both A records.

    – Sandman4
    Nov 7 '11 at 7:47











  • Is there an A record for ns-1 in the cache ? - might be the cause. Did you try to empty the cache ?

    – Sandman4
    Nov 7 '11 at 13:07
















2















Environment:




  • Active Directory domain with a single domain controller (Windows Server 2003 R2
    Standard x64 Edition - Service Pack 2) which is also the DNS


  • Windows XP Service Pack 3 clients. The client computers have ONLY our internal
    DNS server as their DNS address.



Our users have reported that occasionally they cannot visit Southwest Airlines
website www.southwest.com.



After a few days of trying we were able to reproduce the problem in a test user's
login.



When attempting to access the site in Firefox, the status bar says, "Looking up
www.southwest.com" and after a few moments Firefox displays:



Address Not Found



Firefox can't find the server at www.southwest.com



Similar results in Internet Explorer



We tried restarting the browser and the computer, but we still cannot access the
site. Other websites we tested work normally.



We tried accessing the website from another computer and got the same results.



nslookup reveals the following:



C:Documents and SettingsTestQ>nslookup www.teamdesk.net
Server: server.domain.local
Address: 172.21.31.206

Name: www.teamdesk.net
Address: 208.100.33.78


C:Documents and SettingsTestQ>nslookup www.southwest.com
Server: server.domain.local
Address: 172.21.31.206

DNS request timed out.
timeout was 2 seconds.
*** Request to server.domain.local timed-out


C:Documents and SettingsTestQ>nslookup
Default Server: server.domain.local
Address: 172.21.31.206

> www.southwest.com
Server: server.domain.local
Address: 172.21.31.206

DNS request timed out.
timeout was 2 seconds.
*** Request to server.domain.local timed-out

> set d2
> www.southwest.com
Server: server.domain.local
Address: 172.21.31.206

------------
SendRequest(), len 51
HEADER:
opcode = QUERY, id = 4, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
www.southwest.com.domain.local, type = A, class = IN

------------
------------
Got answer (119 bytes):
HEADER:
opcode = QUERY, id = 4, rcode = NXDOMAIN
header flags: response, auth. answer, want recursion, recursion avail.
questions = 1, answers = 0, authority records = 1, additional = 0

QUESTIONS:
www.southwest.com.domain.local, type = A, class = IN
AUTHORITY RECORDS:
-> domain.local
type = SOA, class = IN, dlen = 41
ttl = 3600 (1 hour)
primary name server = server.domain.local
responsible mail addr = hostmaster
serial = 2064
refresh = 900 (15 mins)
retry = 600 (10 mins)
expire = 86400 (1 day)
default TTL = 3600 (1 hour)

------------
------------
SendRequest(), len 35
HEADER:
opcode = QUERY, id = 5, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
www.southwest.com, type = A, class = IN

------------
DNS request timed out.
timeout was 2 seconds.
timeout (2 secs)
SendRequest failed
*** Request to server.domain.local timed-out


> www.google.com
Server: server.domain.local
Address: 172.21.31.206

------------
SendRequest(), len 48
HEADER:
opcode = QUERY, id = 6, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
www.google.com.domain.local, type = A, class = IN

------------
------------
Got answer (116 bytes):
HEADER:
opcode = QUERY, id = 6, rcode = NXDOMAIN
header flags: response, auth. answer, want recursion, recursion avail.
questions = 1, answers = 0, authority records = 1, additional = 0

QUESTIONS:
www.google.com.domain.local, type = A, class = IN
AUTHORITY RECORDS:
-> domain.local
type = SOA, class = IN, dlen = 41
ttl = 3600 (1 hour)
primary name server = server.domain.local
responsible mail addr = hostmaster
serial = 2064
refresh = 900 (15 mins)
retry = 600 (10 mins)
expire = 86400 (1 day)
default TTL = 3600 (1 hour)

------------
------------
SendRequest(), len 32
HEADER:
opcode = QUERY, id = 7, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
www.google.com, type = A, class = IN

------------
------------
Got answer (132 bytes):
HEADER:
opcode = QUERY, id = 7, rcode = NOERROR
header flags: response, want recursion, recursion avail.
questions = 1, answers = 6, authority records = 0, additional = 0

QUESTIONS:
www.google.com, type = A, class = IN
ANSWERS:
-> www.google.com
type = CNAME, class = IN, dlen = 8
canonical name = www.l.google.com
ttl = 69859 (19 hours 24 mins 19 secs)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.19
ttl = 300 (5 mins)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.20
ttl = 300 (5 mins)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.18
ttl = 300 (5 mins)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.17
ttl = 300 (5 mins)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.16
ttl = 300 (5 mins)

------------
Non-authoritative answer:
Name: www.l.google.com
Addresses: 74.125.239.19, 74.125.239.20, 74.125.239.18, 74.125.239.17
74.125.239.16
Aliases: www.google.com


How do we further diagnose and resolve this problem?



EDIT



I work with Brad. Thanks for your help so far.



1) The DNS server acts as the resolver. There is no forward lookup other than the root servers via root hints.



2) Under the error state (i.e., when the southwest.com lookups are timing out), nslookup southwest.com ns-1.southwest.com times out looking up the ns-1.southwest.com server. Same thing with ns-2.southwest.com.



3) Under the error state, nslookup southwest.com 12.5.136.190 and nslookup southwest.com 63.169.44.190 (i.e., against the IP addresses of ns-1 and ns-2.southwest.com) both work, returning southwest.com's IP addresses.



4) Under the error state, the cache is unchanged from when things are working normally. That is, dnsmgmtcached lookups.(root)comsouthwest always shows the following (including the A record for ns-2, which fails (see #2 above)).



Name                        Type                Data
---- ---- ----
(same as parent folder) Name Server (NS) ns-1.southwest.com
(same as parent folder) Name Server (NS) ns-2.southwest.com
(same as parent folder) Host (A) 208.94.152.100
(same as parent folder) Host (A) 208.94.153.100
ns-2 Host (A) 63.169.44.190


I suspect we're overlooking something obvious ...



EDIT



(Sorry for the delay. I posted this over 8 hours ago but it never appeared.)



Under the error state,



5) nslookup southwest.com against all *.gtld-servers.net servers succeeded



... QUESTIONS:
southwest.com, type = A, class = IN
AUTHORITY RECORDS:
-> southwest.com
type = NS, class = IN, dlen = 7
nameserver = ns-1.southwest.com
ttl = 172800 (2 days)
-> southwest.com
type = NS, class = IN, dlen = 7
nameserver = ns-2.southwest.com
ttl = 172800 (2 days)
ADDITIONAL RECORDS:
-> ns-1.southwest.com
type = A, class = IN, dlen = 4
internet address = 12.5.136.190
ttl = 172800 (2 days)
-> ns-2.southwest.com
type = A, class = IN, dlen = 4
internet address = 63.169.44.190
ttl = 172800 (2 days)

------------
Name: southwest.com
Served by:
- ns-1.southwest.com
12.5.136.190
southwest.com
- ns-2.southwest.com
63.169.44.190
southwest.com


6) nslookup southwest.com 208.67.222.222 (OpenDNS) succeeded



7) Clearing the cache fixed the problem, but it just returns later.



8) After clearing the cache and doing nslookup southwest.com (which succeeds), the cache now has ns-1's A record (it didn't under the error state, see #4 above)



Name                        Type                Data
---- ---- ----
(same as parent folder) Name Server (NS) ns-1.southwest.com
(same as parent folder) Name Server (NS) ns-2.southwest.com
(same as parent folder) Host (A) 208.94.153.100
(same as parent folder) Host (A) 208.94.152.100
ns-1 Host (A) 12.5.136.190
ns-2 Host (A) 63.169.44.190


9) Note that the DNS server only forwards to the root servers. Can you think of any reason that should cause this problem?










share|improve this question
















bumped to the homepage by Community 5 hours ago


This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
















  • maybe from your DNS server, try nslookup www.southwest.com ns-1.southwest.com and nslookup www.southwest.com ns-2.southwest.com This will show if your DNS server can access their DNS servers.

    – Sandman4
    Nov 6 '11 at 19:00











  • btw, your DNS server - how it configured - it acts as resolver or it merely forwards requests to your ISP ? - in the latter case, try nslookup www.southwest.com nsX.yourisp.net

    – Sandman4
    Nov 6 '11 at 19:03











  • Also, the L root IP is current.

    – user100178
    Nov 7 '11 at 3:55











  • Since the problems is looking-up nameservers names, now, you may try nslookup southwest.com a.gtld-servers.net ... m.gtld-serves.net. See if all requests answered and return both NS and both A records.

    – Sandman4
    Nov 7 '11 at 7:47











  • Is there an A record for ns-1 in the cache ? - might be the cause. Did you try to empty the cache ?

    – Sandman4
    Nov 7 '11 at 13:07














2












2








2








Environment:




  • Active Directory domain with a single domain controller (Windows Server 2003 R2
    Standard x64 Edition - Service Pack 2) which is also the DNS


  • Windows XP Service Pack 3 clients. The client computers have ONLY our internal
    DNS server as their DNS address.



Our users have reported that occasionally they cannot visit Southwest Airlines
website www.southwest.com.



After a few days of trying we were able to reproduce the problem in a test user's
login.



When attempting to access the site in Firefox, the status bar says, "Looking up
www.southwest.com" and after a few moments Firefox displays:



Address Not Found



Firefox can't find the server at www.southwest.com



Similar results in Internet Explorer



We tried restarting the browser and the computer, but we still cannot access the
site. Other websites we tested work normally.



We tried accessing the website from another computer and got the same results.



nslookup reveals the following:



C:Documents and SettingsTestQ>nslookup www.teamdesk.net
Server: server.domain.local
Address: 172.21.31.206

Name: www.teamdesk.net
Address: 208.100.33.78


C:Documents and SettingsTestQ>nslookup www.southwest.com
Server: server.domain.local
Address: 172.21.31.206

DNS request timed out.
timeout was 2 seconds.
*** Request to server.domain.local timed-out


C:Documents and SettingsTestQ>nslookup
Default Server: server.domain.local
Address: 172.21.31.206

> www.southwest.com
Server: server.domain.local
Address: 172.21.31.206

DNS request timed out.
timeout was 2 seconds.
*** Request to server.domain.local timed-out

> set d2
> www.southwest.com
Server: server.domain.local
Address: 172.21.31.206

------------
SendRequest(), len 51
HEADER:
opcode = QUERY, id = 4, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
www.southwest.com.domain.local, type = A, class = IN

------------
------------
Got answer (119 bytes):
HEADER:
opcode = QUERY, id = 4, rcode = NXDOMAIN
header flags: response, auth. answer, want recursion, recursion avail.
questions = 1, answers = 0, authority records = 1, additional = 0

QUESTIONS:
www.southwest.com.domain.local, type = A, class = IN
AUTHORITY RECORDS:
-> domain.local
type = SOA, class = IN, dlen = 41
ttl = 3600 (1 hour)
primary name server = server.domain.local
responsible mail addr = hostmaster
serial = 2064
refresh = 900 (15 mins)
retry = 600 (10 mins)
expire = 86400 (1 day)
default TTL = 3600 (1 hour)

------------
------------
SendRequest(), len 35
HEADER:
opcode = QUERY, id = 5, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
www.southwest.com, type = A, class = IN

------------
DNS request timed out.
timeout was 2 seconds.
timeout (2 secs)
SendRequest failed
*** Request to server.domain.local timed-out


> www.google.com
Server: server.domain.local
Address: 172.21.31.206

------------
SendRequest(), len 48
HEADER:
opcode = QUERY, id = 6, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
www.google.com.domain.local, type = A, class = IN

------------
------------
Got answer (116 bytes):
HEADER:
opcode = QUERY, id = 6, rcode = NXDOMAIN
header flags: response, auth. answer, want recursion, recursion avail.
questions = 1, answers = 0, authority records = 1, additional = 0

QUESTIONS:
www.google.com.domain.local, type = A, class = IN
AUTHORITY RECORDS:
-> domain.local
type = SOA, class = IN, dlen = 41
ttl = 3600 (1 hour)
primary name server = server.domain.local
responsible mail addr = hostmaster
serial = 2064
refresh = 900 (15 mins)
retry = 600 (10 mins)
expire = 86400 (1 day)
default TTL = 3600 (1 hour)

------------
------------
SendRequest(), len 32
HEADER:
opcode = QUERY, id = 7, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
www.google.com, type = A, class = IN

------------
------------
Got answer (132 bytes):
HEADER:
opcode = QUERY, id = 7, rcode = NOERROR
header flags: response, want recursion, recursion avail.
questions = 1, answers = 6, authority records = 0, additional = 0

QUESTIONS:
www.google.com, type = A, class = IN
ANSWERS:
-> www.google.com
type = CNAME, class = IN, dlen = 8
canonical name = www.l.google.com
ttl = 69859 (19 hours 24 mins 19 secs)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.19
ttl = 300 (5 mins)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.20
ttl = 300 (5 mins)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.18
ttl = 300 (5 mins)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.17
ttl = 300 (5 mins)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.16
ttl = 300 (5 mins)

------------
Non-authoritative answer:
Name: www.l.google.com
Addresses: 74.125.239.19, 74.125.239.20, 74.125.239.18, 74.125.239.17
74.125.239.16
Aliases: www.google.com


How do we further diagnose and resolve this problem?



EDIT



I work with Brad. Thanks for your help so far.



1) The DNS server acts as the resolver. There is no forward lookup other than the root servers via root hints.



2) Under the error state (i.e., when the southwest.com lookups are timing out), nslookup southwest.com ns-1.southwest.com times out looking up the ns-1.southwest.com server. Same thing with ns-2.southwest.com.



3) Under the error state, nslookup southwest.com 12.5.136.190 and nslookup southwest.com 63.169.44.190 (i.e., against the IP addresses of ns-1 and ns-2.southwest.com) both work, returning southwest.com's IP addresses.



4) Under the error state, the cache is unchanged from when things are working normally. That is, dnsmgmtcached lookups.(root)comsouthwest always shows the following (including the A record for ns-2, which fails (see #2 above)).



Name                        Type                Data
---- ---- ----
(same as parent folder) Name Server (NS) ns-1.southwest.com
(same as parent folder) Name Server (NS) ns-2.southwest.com
(same as parent folder) Host (A) 208.94.152.100
(same as parent folder) Host (A) 208.94.153.100
ns-2 Host (A) 63.169.44.190


I suspect we're overlooking something obvious ...



EDIT



(Sorry for the delay. I posted this over 8 hours ago but it never appeared.)



Under the error state,



5) nslookup southwest.com against all *.gtld-servers.net servers succeeded



... QUESTIONS:
southwest.com, type = A, class = IN
AUTHORITY RECORDS:
-> southwest.com
type = NS, class = IN, dlen = 7
nameserver = ns-1.southwest.com
ttl = 172800 (2 days)
-> southwest.com
type = NS, class = IN, dlen = 7
nameserver = ns-2.southwest.com
ttl = 172800 (2 days)
ADDITIONAL RECORDS:
-> ns-1.southwest.com
type = A, class = IN, dlen = 4
internet address = 12.5.136.190
ttl = 172800 (2 days)
-> ns-2.southwest.com
type = A, class = IN, dlen = 4
internet address = 63.169.44.190
ttl = 172800 (2 days)

------------
Name: southwest.com
Served by:
- ns-1.southwest.com
12.5.136.190
southwest.com
- ns-2.southwest.com
63.169.44.190
southwest.com


6) nslookup southwest.com 208.67.222.222 (OpenDNS) succeeded



7) Clearing the cache fixed the problem, but it just returns later.



8) After clearing the cache and doing nslookup southwest.com (which succeeds), the cache now has ns-1's A record (it didn't under the error state, see #4 above)



Name                        Type                Data
---- ---- ----
(same as parent folder) Name Server (NS) ns-1.southwest.com
(same as parent folder) Name Server (NS) ns-2.southwest.com
(same as parent folder) Host (A) 208.94.153.100
(same as parent folder) Host (A) 208.94.152.100
ns-1 Host (A) 12.5.136.190
ns-2 Host (A) 63.169.44.190


9) Note that the DNS server only forwards to the root servers. Can you think of any reason that should cause this problem?










share|improve this question
















Environment:




  • Active Directory domain with a single domain controller (Windows Server 2003 R2
    Standard x64 Edition - Service Pack 2) which is also the DNS


  • Windows XP Service Pack 3 clients. The client computers have ONLY our internal
    DNS server as their DNS address.



Our users have reported that occasionally they cannot visit Southwest Airlines
website www.southwest.com.



After a few days of trying we were able to reproduce the problem in a test user's
login.



When attempting to access the site in Firefox, the status bar says, "Looking up
www.southwest.com" and after a few moments Firefox displays:



Address Not Found



Firefox can't find the server at www.southwest.com



Similar results in Internet Explorer



We tried restarting the browser and the computer, but we still cannot access the
site. Other websites we tested work normally.



We tried accessing the website from another computer and got the same results.



nslookup reveals the following:



C:Documents and SettingsTestQ>nslookup www.teamdesk.net
Server: server.domain.local
Address: 172.21.31.206

Name: www.teamdesk.net
Address: 208.100.33.78


C:Documents and SettingsTestQ>nslookup www.southwest.com
Server: server.domain.local
Address: 172.21.31.206

DNS request timed out.
timeout was 2 seconds.
*** Request to server.domain.local timed-out


C:Documents and SettingsTestQ>nslookup
Default Server: server.domain.local
Address: 172.21.31.206

> www.southwest.com
Server: server.domain.local
Address: 172.21.31.206

DNS request timed out.
timeout was 2 seconds.
*** Request to server.domain.local timed-out

> set d2
> www.southwest.com
Server: server.domain.local
Address: 172.21.31.206

------------
SendRequest(), len 51
HEADER:
opcode = QUERY, id = 4, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
www.southwest.com.domain.local, type = A, class = IN

------------
------------
Got answer (119 bytes):
HEADER:
opcode = QUERY, id = 4, rcode = NXDOMAIN
header flags: response, auth. answer, want recursion, recursion avail.
questions = 1, answers = 0, authority records = 1, additional = 0

QUESTIONS:
www.southwest.com.domain.local, type = A, class = IN
AUTHORITY RECORDS:
-> domain.local
type = SOA, class = IN, dlen = 41
ttl = 3600 (1 hour)
primary name server = server.domain.local
responsible mail addr = hostmaster
serial = 2064
refresh = 900 (15 mins)
retry = 600 (10 mins)
expire = 86400 (1 day)
default TTL = 3600 (1 hour)

------------
------------
SendRequest(), len 35
HEADER:
opcode = QUERY, id = 5, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
www.southwest.com, type = A, class = IN

------------
DNS request timed out.
timeout was 2 seconds.
timeout (2 secs)
SendRequest failed
*** Request to server.domain.local timed-out


> www.google.com
Server: server.domain.local
Address: 172.21.31.206

------------
SendRequest(), len 48
HEADER:
opcode = QUERY, id = 6, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
www.google.com.domain.local, type = A, class = IN

------------
------------
Got answer (116 bytes):
HEADER:
opcode = QUERY, id = 6, rcode = NXDOMAIN
header flags: response, auth. answer, want recursion, recursion avail.
questions = 1, answers = 0, authority records = 1, additional = 0

QUESTIONS:
www.google.com.domain.local, type = A, class = IN
AUTHORITY RECORDS:
-> domain.local
type = SOA, class = IN, dlen = 41
ttl = 3600 (1 hour)
primary name server = server.domain.local
responsible mail addr = hostmaster
serial = 2064
refresh = 900 (15 mins)
retry = 600 (10 mins)
expire = 86400 (1 day)
default TTL = 3600 (1 hour)

------------
------------
SendRequest(), len 32
HEADER:
opcode = QUERY, id = 7, rcode = NOERROR
header flags: query, want recursion
questions = 1, answers = 0, authority records = 0, additional = 0

QUESTIONS:
www.google.com, type = A, class = IN

------------
------------
Got answer (132 bytes):
HEADER:
opcode = QUERY, id = 7, rcode = NOERROR
header flags: response, want recursion, recursion avail.
questions = 1, answers = 6, authority records = 0, additional = 0

QUESTIONS:
www.google.com, type = A, class = IN
ANSWERS:
-> www.google.com
type = CNAME, class = IN, dlen = 8
canonical name = www.l.google.com
ttl = 69859 (19 hours 24 mins 19 secs)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.19
ttl = 300 (5 mins)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.20
ttl = 300 (5 mins)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.18
ttl = 300 (5 mins)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.17
ttl = 300 (5 mins)
-> www.l.google.com
type = A, class = IN, dlen = 4
internet address = 74.125.239.16
ttl = 300 (5 mins)

------------
Non-authoritative answer:
Name: www.l.google.com
Addresses: 74.125.239.19, 74.125.239.20, 74.125.239.18, 74.125.239.17
74.125.239.16
Aliases: www.google.com


How do we further diagnose and resolve this problem?



EDIT



I work with Brad. Thanks for your help so far.



1) The DNS server acts as the resolver. There is no forward lookup other than the root servers via root hints.



2) Under the error state (i.e., when the southwest.com lookups are timing out), nslookup southwest.com ns-1.southwest.com times out looking up the ns-1.southwest.com server. Same thing with ns-2.southwest.com.



3) Under the error state, nslookup southwest.com 12.5.136.190 and nslookup southwest.com 63.169.44.190 (i.e., against the IP addresses of ns-1 and ns-2.southwest.com) both work, returning southwest.com's IP addresses.



4) Under the error state, the cache is unchanged from when things are working normally. That is, dnsmgmtcached lookups.(root)comsouthwest always shows the following (including the A record for ns-2, which fails (see #2 above)).



Name                        Type                Data
---- ---- ----
(same as parent folder) Name Server (NS) ns-1.southwest.com
(same as parent folder) Name Server (NS) ns-2.southwest.com
(same as parent folder) Host (A) 208.94.152.100
(same as parent folder) Host (A) 208.94.153.100
ns-2 Host (A) 63.169.44.190


I suspect we're overlooking something obvious ...



EDIT



(Sorry for the delay. I posted this over 8 hours ago but it never appeared.)



Under the error state,



5) nslookup southwest.com against all *.gtld-servers.net servers succeeded



... QUESTIONS:
southwest.com, type = A, class = IN
AUTHORITY RECORDS:
-> southwest.com
type = NS, class = IN, dlen = 7
nameserver = ns-1.southwest.com
ttl = 172800 (2 days)
-> southwest.com
type = NS, class = IN, dlen = 7
nameserver = ns-2.southwest.com
ttl = 172800 (2 days)
ADDITIONAL RECORDS:
-> ns-1.southwest.com
type = A, class = IN, dlen = 4
internet address = 12.5.136.190
ttl = 172800 (2 days)
-> ns-2.southwest.com
type = A, class = IN, dlen = 4
internet address = 63.169.44.190
ttl = 172800 (2 days)

------------
Name: southwest.com
Served by:
- ns-1.southwest.com
12.5.136.190
southwest.com
- ns-2.southwest.com
63.169.44.190
southwest.com


6) nslookup southwest.com 208.67.222.222 (OpenDNS) succeeded



7) Clearing the cache fixed the problem, but it just returns later.



8) After clearing the cache and doing nslookup southwest.com (which succeeds), the cache now has ns-1's A record (it didn't under the error state, see #4 above)



Name                        Type                Data
---- ---- ----
(same as parent folder) Name Server (NS) ns-1.southwest.com
(same as parent folder) Name Server (NS) ns-2.southwest.com
(same as parent folder) Host (A) 208.94.153.100
(same as parent folder) Host (A) 208.94.152.100
ns-1 Host (A) 12.5.136.190
ns-2 Host (A) 63.169.44.190


9) Note that the DNS server only forwards to the root servers. Can you think of any reason that should cause this problem?







domain-name-system active-directory






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 8 '11 at 3:26









Community

1




1










asked Nov 6 '11 at 18:39









Brad HeipleBrad Heiple

347




347





bumped to the homepage by Community 5 hours ago


This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.







bumped to the homepage by Community 5 hours ago


This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.















  • maybe from your DNS server, try nslookup www.southwest.com ns-1.southwest.com and nslookup www.southwest.com ns-2.southwest.com This will show if your DNS server can access their DNS servers.

    – Sandman4
    Nov 6 '11 at 19:00











  • btw, your DNS server - how it configured - it acts as resolver or it merely forwards requests to your ISP ? - in the latter case, try nslookup www.southwest.com nsX.yourisp.net

    – Sandman4
    Nov 6 '11 at 19:03











  • Also, the L root IP is current.

    – user100178
    Nov 7 '11 at 3:55











  • Since the problems is looking-up nameservers names, now, you may try nslookup southwest.com a.gtld-servers.net ... m.gtld-serves.net. See if all requests answered and return both NS and both A records.

    – Sandman4
    Nov 7 '11 at 7:47











  • Is there an A record for ns-1 in the cache ? - might be the cause. Did you try to empty the cache ?

    – Sandman4
    Nov 7 '11 at 13:07



















  • maybe from your DNS server, try nslookup www.southwest.com ns-1.southwest.com and nslookup www.southwest.com ns-2.southwest.com This will show if your DNS server can access their DNS servers.

    – Sandman4
    Nov 6 '11 at 19:00











  • btw, your DNS server - how it configured - it acts as resolver or it merely forwards requests to your ISP ? - in the latter case, try nslookup www.southwest.com nsX.yourisp.net

    – Sandman4
    Nov 6 '11 at 19:03











  • Also, the L root IP is current.

    – user100178
    Nov 7 '11 at 3:55











  • Since the problems is looking-up nameservers names, now, you may try nslookup southwest.com a.gtld-servers.net ... m.gtld-serves.net. See if all requests answered and return both NS and both A records.

    – Sandman4
    Nov 7 '11 at 7:47











  • Is there an A record for ns-1 in the cache ? - might be the cause. Did you try to empty the cache ?

    – Sandman4
    Nov 7 '11 at 13:07

















maybe from your DNS server, try nslookup www.southwest.com ns-1.southwest.com and nslookup www.southwest.com ns-2.southwest.com This will show if your DNS server can access their DNS servers.

– Sandman4
Nov 6 '11 at 19:00





maybe from your DNS server, try nslookup www.southwest.com ns-1.southwest.com and nslookup www.southwest.com ns-2.southwest.com This will show if your DNS server can access their DNS servers.

– Sandman4
Nov 6 '11 at 19:00













btw, your DNS server - how it configured - it acts as resolver or it merely forwards requests to your ISP ? - in the latter case, try nslookup www.southwest.com nsX.yourisp.net

– Sandman4
Nov 6 '11 at 19:03





btw, your DNS server - how it configured - it acts as resolver or it merely forwards requests to your ISP ? - in the latter case, try nslookup www.southwest.com nsX.yourisp.net

– Sandman4
Nov 6 '11 at 19:03













Also, the L root IP is current.

– user100178
Nov 7 '11 at 3:55





Also, the L root IP is current.

– user100178
Nov 7 '11 at 3:55













Since the problems is looking-up nameservers names, now, you may try nslookup southwest.com a.gtld-servers.net ... m.gtld-serves.net. See if all requests answered and return both NS and both A records.

– Sandman4
Nov 7 '11 at 7:47





Since the problems is looking-up nameservers names, now, you may try nslookup southwest.com a.gtld-servers.net ... m.gtld-serves.net. See if all requests answered and return both NS and both A records.

– Sandman4
Nov 7 '11 at 7:47













Is there an A record for ns-1 in the cache ? - might be the cause. Did you try to empty the cache ?

– Sandman4
Nov 7 '11 at 13:07





Is there an A record for ns-1 in the cache ? - might be the cause. Did you try to empty the cache ?

– Sandman4
Nov 7 '11 at 13:07










1 Answer
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If you forward DNS to your ISP, try doing an nslookup specifying their servers and see if the problem is on their end. If you are using root hints, make sure that the L root server root hint is using the right IP. I've seen that cause some wonkiness on older AD installs.






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    If you forward DNS to your ISP, try doing an nslookup specifying their servers and see if the problem is on their end. If you are using root hints, make sure that the L root server root hint is using the right IP. I've seen that cause some wonkiness on older AD installs.






    share|improve this answer




























      0














      If you forward DNS to your ISP, try doing an nslookup specifying their servers and see if the problem is on their end. If you are using root hints, make sure that the L root server root hint is using the right IP. I've seen that cause some wonkiness on older AD installs.






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        If you forward DNS to your ISP, try doing an nslookup specifying their servers and see if the problem is on their end. If you are using root hints, make sure that the L root server root hint is using the right IP. I've seen that cause some wonkiness on older AD installs.






        share|improve this answer













        If you forward DNS to your ISP, try doing an nslookup specifying their servers and see if the problem is on their end. If you are using root hints, make sure that the L root server root hint is using the right IP. I've seen that cause some wonkiness on older AD installs.







        share|improve this answer












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        share|improve this answer










        answered Nov 6 '11 at 19:07









        MDMarraMDMarra

        92.8k27174314




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