DHCP and DNS

[Guest]

This is a repost of a question from a couple of weeks ago. I'm hoping
someone can point me to some more information, other than a suggestion to
'diagnose the problem'. Any help is appreciated.

I have about 120 Win XP Pro users on my network, all configured to use DHCP.
Most network fuctions are working well, but I have recently found a name
resolution problem after adding a new host to the network.

About 10% of the users cannot resolve the new host name. If I ping the
host, I get the message "ping request could not find host". But if I run
nslookup, I get the correct IP address immediately. The responses are the
same if I use the simple host name or the FQDN.

I have run ipconfig /flushdns countless times with no effect. (I have
noticed that even after running /flushdns some machines still have many
entries when I run /displaydns.)

I can make name resolution work by changing the IP configuration from
'obtain DNS server address automatically' to 'use the following DNS server
addresses' and specifying the SAME DNS servers as provided by DHCP. Name
resolution then works. If I change the settings back to automatic, name
resolution works for about 30 minutes and then stops.

From the number of posts on this issue, it seems to be a 'known' issue, but
I have not been able to find a good fix. Does anyone know what the root
cause is, and how to fix it?

Thanks,
Joe

 

[Robert L [MVP - Networking]]

Assuming you can ping the computer by IP, can you ping it by FQDN?

Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
This is a repost of a question from a couple of weeks ago. I'm hoping
someone can point me to some more information, other than a suggestion to
'diagnose the problem'. Any help is appreciated.

I have about 120 Win XP Pro users on my network, all configured to use DHCP.
Most network fuctions are working well, but I have recently found a name
resolution problem after adding a new host to the network.

About 10% of the users cannot resolve the new host name. If I ping the
host, I get the message "ping request could not find host". But if I run
nslookup, I get the correct IP address immediately. The responses are the
same if I use the simple host name or the FQDN.

I have run ipconfig /flushdns countless times with no effect. (I have
noticed that even after running /flushdns some machines still have many
entries when I run /displaydns.)

I can make name resolution work by changing the IP configuration from
'obtain DNS server address automatically' to 'use the following DNS server
addresses' and specifying the SAME DNS servers as provided by DHCP. Name
resolution then works. If I change the settings back to automatic, name
resolution works for about 30 minutes and then stops.

From the number of posts on this issue, it seems to be a 'known' issue, but
I have not been able to find a good fix. Does anyone know what the root
cause is, and how to fix it?

Thanks,
Joe

 

[Guest]

Bob,
Negative. Per my post below, I cannot ping it using either the simple host
name or FQDN. I can ping it using IP address, so routing is not an issue.

Thanks,
Joe

 

[Thufir]

Per my post below, I cannot ping it using either the simple host name or
FQDN. I can ping it using IP address, so routing is not an issue.

What's the distinction between the FQDN and "simple host name"? A FQDN
would be, for instance, wikipedia.org?

as in:

arrakis ~ #
arrakis ~ #
arrakis ~ #
arrakis ~ # nslookup wikipedia.org
Server: 192.168.2.1
Address: 192.168.2.1#53

Non-authoritative answer:
Name: wikipedia.org
Address: 66.230.200.100

arrakis ~ #
arrakis ~ # date
Sun Sep 2 17:44:45 PDT 2007
arrakis ~ #


what are your results?


-Thufir

 

[Guest]

A FQDN is hostname.domainname.com versus only specifying the hostname. Since
this is an INTERNAL name resolution issue, the AD DNS servers will append a
domain name to any simple query.

So, if I ping 'hostname', I get the same results as if I ping
'hostname.domainname.com'

Regarding the issue at hand, NEITHER approach works. I can do an nslookup
on either name and it works, but if I ping either name, I get the 'could not
find host' error.

To recap, this situation only occurs for users with DHCP aquired DNS
servers. If the DNS servers are set manually, everything works.

Thanks,
Joe