DNS works, DNS fails, DNS is being flaky!!!

I am running my own DNS server ... and that _may_ have something to do with my problems.

But every time I ask _my_ DNS server for the right answer for my domain, it works fine.  When I ask some others around the web, all is well.

But the DNS that my broadband ISP provides often cannot find my site or any of its subdomains.

I realize that for development, i can just put in a HOSTS entry.  But my customer cannot expect all his personnel to do the same.

See the attached NSLookup results. MySite and 111.222.111.222 are, of course, masking the real identity.  But everything else is as I find it.

I'd love to just blame Verizon.  But my customer occassionally has the same problem from his LAN.  And Verizon is failing to resolve other sites for me ... so I suspect it's my own server.  But ... every time I ask my server, it has the right answer.

Any ideas what's really wrong & how to fix it?

Thanks!
C:\Users\Daniel>nslookup ics.MySite.com
Server:  44.sub-66-174-95.myvzw.com
Address:  66.174.95.44

*** 44.sub-66-174-95.myvzw.com can't find ics.MySite.com: Server failed

C:\Users\Daniel>nslookup ics.MySite.com
Server:  44.sub-66-174-95.myvzw.com
Address:  66.174.95.44

Non-authoritative answer:
Name:    MySite.com
Address:  111.222.111.222
Aliases:  ics.MySite.com


C:\Users\Daniel>nslookup crs.MySite.com
Server:  44.sub-66-174-95.myvzw.com
Address:  66.174.95.44

Non-authoritative answer:
Name:    MySite.com
Address:  111.222.111.222
Aliases:  crs.MySite.com


C:\Users\Daniel>nslookup crs.MySite.com
Server:  44.sub-66-174-95.myvzw.com
Address:  66.174.95.44

*** 44.sub-66-174-95.myvzw.com can't find crs.MySite.com: Server failed

C:\Users\Daniel>nslookup crs.MySite.com
Server:  44.sub-66-174-95.myvzw.com
Address:  66.174.95.44

*** 44.sub-66-174-95.myvzw.com can't find crs.MySite.com: Server failed

C:\Users\Daniel>nslookup ics.MySite.com
Server:  44.sub-66-174-95.myvzw.com
Address:  66.174.95.44

*** 44.sub-66-174-95.myvzw.com can't find ics.MySite.com: Server failed

C:\Users\Daniel>nslookup www.MySite.com
Server:  44.sub-66-174-95.myvzw.com
Address:  66.174.95.44

*** 44.sub-66-174-95.myvzw.com can't find www.MySite.com: Server failed

C:\Users\Daniel>nslookup www.MySite.com
Server:  44.sub-66-174-95.myvzw.com
Address:  66.174.95.44

*** 44.sub-66-174-95.myvzw.com can't find www.MySite.com: Server failed

C:\Users\Daniel>nslookup dev.MySite.com
Server:  44.sub-66-174-95.myvzw.com
Address:  66.174.95.44

Non-authoritative answer:
Name:    dev.MySite.com
Address:  111.222.111.222


C:\Users\Daniel>nslookup dev.MySite.com
Server:  44.sub-66-174-95.myvzw.com
Address:  66.174.95.44

Non-authoritative answer:
Name:    dev.MySite.com
Address:  111.222.111.222


C:\Users\Daniel>nslookup dev.MySite.com
Server:  44.sub-66-174-95.myvzw.com
Address:  66.174.95.44

*** 44.sub-66-174-95.myvzw.com can't find dev.MySite.com: Server failed

C:\Users\Daniel>nslookup www.MySite.com
Server:  44.sub-66-174-95.myvzw.com
Address:  66.174.95.44

*** 44.sub-66-174-95.myvzw.com can't find www.MySite.com: Server failed

C:\Users\Daniel>nslookup ics.MySite.com
Server:  44.sub-66-174-95.myvzw.com
Address:  66.174.95.44

*** 44.sub-66-174-95.myvzw.com can't find ics.MySite.com: Server failed

C:\Users\Daniel>

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LVL 32
Daniel WilsonAsked:
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OnlyodinCommented:
Try Google DNS or OpenDNS:

Google DNS Servers:
8.8.8.8
8.8.4.4

OpenDNS Servers:
208.67.222.222
208.67.220.220

If you can resolve consistently with either of those, you can either use them ongoing (for free), or it will help you get information to take back to your provider to get them to fix their servers.

As stated before, both are free, although OpenDNS allows you to do some DNS level filtering amongst other things.
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OnlyodinCommented:
Also, if your DNS Server is not using explicit forwarders, it will be looking domains up directly via root hints, bypassing verizon's (potentially) faulty nameservers.

This could help to explain why your server always has an accurate response.
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Daniel WilsonAuthor Commented:
I tried the Google ones before ... and seemed to do fine with them.

So ... do I suggest that all my customer's personnel all switch to Google DNS instead of their ISPs'?

What information should I look for from either Google DNS or OpenDNS that I can tell the various ISP's so they get their acts together?

Thanks!
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giltjrCommented:
Other DNS servers may be caching responses from your DNS server for longer than you have specified.  Some ISP's DNS servers will ignore your TTL and cache entries for a week no matter what.

Verizon may be caching your entries based on your TTL and so they need to query your DNS server more often.

What type and speed is the Internet connection for your DNS server?  Could the link be 100% utilizited for a brief amount of time?  All it takes is 3-5 seconds.  

Is your DNS server running any other services that could cause it to have a slight performance problem every now and then?
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Chris DentPowerShell DeveloperCommented:
Whether you use Google or not the series of commands should have worked.

You should check that all DNS servers responsible for that domain are returning consistent responses.

Run:

nslookup -q=ns MySite.com

Then for each of the name servers returned run:

nslookup www.MySite.com ServerNameOrIP

Or run the same for one of the other failing names.

You also need to check the delegation of each of these from the parent down to your server. Is it really .com? Otherwise you'll need to get a DNS resolver capable of performing an Iterative query (like Dig for Windows or my DNS resolver, DnsShell :)).

Chris
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ChiefITCommented:
@Chris:

What do you think about putting the router as the forwarding server's IP. Let me explain.

As the ISP's DNS servers are passed down to the router's external NIC through DHCP from the ISP, then those servers will automatically be updated. The verizon servers may have gone off line for maintenance or changed the IP. So, maybe one of the ISPs DNS server in the forwarders list is down, causing intermittent problems with reaching the web sites. By using the router as a forwarder, you get the latest info passed down from the ISP as a forwarder server. I have done this before and it works pretty well. It's a little trick I learned from KCTS, that I wouldn't have thought of otherwise.

Other than that, DCDiag /test:DNS will check forwarders or Root hints servers to see if they are legit.

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Daniel WilsonAuthor Commented:
>>What type and speed is the Internet connection for your DNS server?  Could the link be 100% utilizited for a brief amount of time?  All it takes is 3-5 seconds.  

It's a LAMP virtual server at my hosting company.  I believe it would be on fractional T3, but I could be mistaken.

>>Is your DNS server running any other services that could cause it to have a slight performance problem every now and then?
Classic LAMP server stuff -- Apache / PHP / MySql / mail server.

Webmin always says CPU utilization is very low (see attached) ... I know that may be taking averages that mask spikes, but averages of 0.00 don't really suggest severe spikes.

My TTL is 38400 -- which I believe is 10 hours & 40 minutes.

VZW will be fine, then for 15 minutes can't resolve, then be fine again.  TTL ... isn't my first suspect on that ... but I'm running out of suspects!

thanks for any further help you can provide!

System uptime 	55 days, 4 hours, 17 minutes
Running processes 	75
CPU load averages 	0.00 (1 min) 0.00 (5 mins) 0.00 (15 mins)
Real memory 	503.57 MB total, 145.42 MB used
	
Virtual memory 	400.02 MB total, 76 kB used
	
Local disk space 	7.55 GB total, 1.93 GB used

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Daniel WilsonAuthor Commented:
>> Is it really .com?

Yes, it is.  
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Daniel WilsonAuthor Commented:
OK, it just started acting up again ...

webmin report attached ...

CPU load averages 	0.27 (1 min) 0.06 (5 mins) 0.02 (15 mins)
Real memory 	503.57 MB total, 125.11 MB used
	
Virtual memory 	400.02 MB total, 76 kB used
	
Local disk space 	7.55 GB total, 1.93 GB used

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giltjrCommented:
Is this a physical server or a virtual server?  If physical, how many CPUs does it have?

Although you are not using that much RAM, 512 MB is not a whole lot of RAM for a LAMP server, it almost appears as if you re doing nothing right now with it.

If you have a physical server with 1 CPU or more it does not look to be that over loaded.  However if it is virtual server then you would need to contact the provider to see if the physical box is having problems.

I would also contact the provider about checking how much bandwidth you are using.
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Daniel WilsonAuthor Commented:
It's virtual.

I'll ask the provider for those reports.  thanks!
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giltjrCommented:
Ah,  in that case you virtual machine may be doing next to nothing, but other virtual machines could be chewing up all of the physical network resources.
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Daniel WilsonAuthor Commented:
My provider referred me to http://www.intodns.com/ which found some errors in my DNS setup.

With those corrected ... it seems to be doing better.

Thanks for the help!
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