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Some computers can ping web IP address but cannot resolve ip to domain name

Posted on 2007-03-27
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Last Modified: 2010-05-18
We have  a small business network consists of 15 computers. 2 people bring their own laptop in to connect to our network.

I have tried both a linksys and d-link router. Some computers can connect to the internet using ip address but not by domain name. (Cannot resolve from domain name to IP).

Please advise. Tried changing DNS server to 3 different ones, not doing a thing.

Please advise.

Thanks.
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Question by:nakedconsulting
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Author Comment

by:nakedconsulting
ID: 18804136
An interesting observation, 2 SBS servers can both connect online, 1 Win XP can connect via anonymizer, while all the other Win XP cannot connect except the 2 laptops.

Please advise.

Thanks.
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Expert Comment

by:mojopojo
ID: 18804192
Q: You have 2 Windows Small Business Servers on one domain? You should not be able to do that and it may be causing your problem.

http://www.microsoft.com/windowsserver2003/sbs/evaluation/topmyths.mspx

A Windows Small Business 2003 server must be the primary DC on any domain. It must hold the global catalogue. And it must be the primary DNS server. All DNS queries on the domain must point to the SBS Server, even itself (server points to itself for DNS resolution).

You can add secondary DC servers, or file servers, or FTP servers... but they must not be SBS.

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by:Mazaraat
ID: 18804259
This sounds like a strictly DNS issue.  I'm assuming your client computers are getting DHCP/DNS from the server?  If not where are they getting it from?

Optimally, one of your SBS servers should be configured to hand out DHCP AND DNS.  In the DNS setup your servers local IP (ex 172.16.1.10) should be listening on, under forwarders put your ISP's DNS server (ex 234.134.5.100).  In DHCP set the scope option (006) DNS Server to your SBS IP that is listening (ex 172.16.1.10).

Any questions?
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Author Comment

by:nakedconsulting
ID: 18804265
It has been working like that for a year. Nothing is going to change that now...
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Author Comment

by:nakedconsulting
ID: 18804284
Everybody is getting DHCP/DNS from the router.
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Expert Comment

by:Mazaraat
ID: 18804301
If they can't browse by domain name, their not getting DNS.  Make sure your router has the correct DNS IP.  To test, go to a client, go to TCPIP properties, change the primary DNS server to the ISP's DNS server, save.  (may require restart) see if you can browse by name....if not, it may be a bad IP?
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Author Comment

by:nakedconsulting
ID: 18804375
I called Verizon and get new DNS servers. I can ping them, they work.
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Author Comment

by:nakedconsulting
ID: 18804379
I use them on the computers too, still not working, please advise.
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by:Mazaraat
ID: 18804388
Check to see if your router has a built in firewall, it may be blocking.  What model of router ar eyou currently using, that way I can lookup the settings.
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by:kmenshouse
ID: 18804547
When you said "it's been working like that for a year", then what has changed now?  Were all the clients able to pull proper DNS before now?  Also, can you tell us what OS the XPs are running - pro or home?  What are the laptops running - pro or home?
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Author Comment

by:nakedconsulting
ID: 18804569
All computers are running pro. One laptop running pro, the other one media center.

Nothing has changed... The problem started with one computer, then another, then another until all but a few of them are working. Yes, everybody was able to pull DNS until now.

DI-634M is the router I'm using.

Thanks.
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Expert Comment

by:robscraig
ID: 18805005
If you set the PC's to static IP's and then do a ipconfig /all what are you getting?

That should at least tell you where your PC's are optaining there DNS and DHCP From.
it sounds to me your SBS servers are improperly forwarding DNS queries.

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Author Comment

by:nakedconsulting
ID: 18805108
They're all on static ip. SBS server doesn't handle DNS or any other internet queres because all traffic points directly to the router.

Thanks.
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Expert Comment

by:screen-name
ID: 18805234
Have you looked into a firmware update for your router? Or reset it, being that you have all your services running on a low end router.

IMHO, you really should run the DNS & DHCP off the server.  Put Verizon's DNS in as fowarders.  But thats just me.

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Expert Comment

by:Wickked
ID: 18805551
IMHO, I think this is due to the firewall filtering the icmp traffic on some of the machines.. I might be wrong tho. Just my 2 cents.
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Expert Comment

by:Rob Hutchinson
ID: 18805839
Well like someone else already said, it's a DNS issue so findout why the DNS servers assigned to the workstations that are having problems are no longer resolving names.

Compare the DNS entries for the good PC's with the bad ones, and find out which DNS entries are no longer working an make sure that none of the clients are using these DNS servers.

I'd do a spreadsheet of all the clients on the network and what IP config's they are all using since you have decided to implement static IP's which is alot more work.
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by:Rob Hutchinson
ID: 18805855
my bad, thought you said you were using static, plz disreguard that part of my comments.
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Expert Comment

by:labtroll
ID: 18806444
You say you have linksys AND dlink routers right?

Given you have 15 + users,  I have to assume you are using one as switch
DI-634M is a wifi router.  which one is connected to WAN?
how are they connected together?  [don't connect the second one from  the wan/internet port to the first main one's lan ports...  lan to lan (linksys routers automatically becomes a switch)]

If you using one as a "switch" then you need to set dhcp off on that one (second one).  set it's ip to the range of the main router.

I'm guess you your doing it this way.  Just file sharing server.  SBS is not used as domain controller, (clients don't log into domain but just simple share) so there's no need to point to the server for DNS.

On client, I always set DNS to the main router IP.

correct me if I'm wrong =)
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Expert Comment

by:labtroll
ID: 18806498
unless something modified the host files on the computers. virus?

oh, nevermind the stuff about linking the router... you wrote "you TRIED both" routers.  Late nights makes bad eyes  =/

As mentioned before.  Reset router and try also update (if any) of firmware.

Also, turn off wireless and just use wire and try. I had similar issue caused by wireless interference and messing up router.

just throwing in some more possibilities.
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Expert Comment

by:cooledit
ID: 18808838
hi, there

what you can try to test TCP/IP stack + DNS.

on a command prompt of a machine working proper.

cmd
nslookup "hit the enter"
what is listed as the DNS server entry
now type google.com enter do you get some respond should say:
64.233.187.99, 72.14.207.99, 64.233.167.99

ok now faulty laptop/desktop
do the same
cmd
nslookup is this the same listed as being the dns server as the one working. if not try this

Type: server "insert the same name as on the one working, or use this one ns1.google.com"
if you use the ns1.google.com it will now be displayed as:
Default Server:  ns1.google.com
Address:  216.239.32.10

now try : microsoft.com and see if this is getting resolved.

Hope that will help you to identify the problem.

Cooledit
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Expert Comment

by:nalanbar
ID: 18816693
I hate to be simplistic, but have you done a ipconfig /flushdns on the bad machines? And also, have you looked in the hosts file?
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Expert Comment

by:darimm
ID: 18817612
You mentioned that you've tried multiple routers, have you ensured that port 53 (outgoing) UDP/TCP (both) are open on your firewall? Is it possible that a recent Microsoft service pack re-enabled the Windows Firewall on your PCs which was previously disabled? This has often come up as a problem in some enviornments I've worked in. The default configuration for the Windows Firewall is pretty bad. If it is enabled on the machines having problems, try disabling it for troubleshooting purposes.

If it was a single machine, I'd say run 'netsh int ip reset c:\resetlog.txt' to "reinstall" TCP/IP, but since it seems like it's more of a group problem, I'm inclined to think it has something to do with ports/firewall settings.
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Author Comment

by:nakedconsulting
ID: 18818634
I found out what it was... It was "Spyware Doctor", the new 5.0 version that's causing the problem on each of the computer.

Thanks.
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