DNS Problem in Server 2003

[dangermouse1977]

Strange Problem here with Win 2003, may be caused by DNS, I'm not sure.

Periodically, the Internet connection at all of my workstations and my server drops out.

When this happens, DNS can still resolve a web address to an IP address, but pings time out.

Checking DNS on the server, the simple test passes fine, the resursive test fails.

I have 2 DNS forwarders set up, 1 to the Internet router and 1 to the ISP's DNS server.

I've not set DNS up from scratch before, so I'm wondering if I've missed something.

Any help gratefully accepted?

Derek

 

[paella33]

DNS caches, both on the clients and on the server, so you can troubleshoot further by clearing the cache on both the clients and the server AND the DNS service.

 

[dangermouse1977]

OK, you've lost me completely.

Remember I've not set up DNS before - can you walk me through it please?

 

[technome]

1 to the Internet router..."
Set the second to one of the ISP's other DNS servers, place a third and forth entry in forwarders to another ISP's DNS servers in case your ISP loses DNS, screws it up, or makes a change without notifying you.




........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[technome]

Came out wrong, skip the forward to the internal router.


........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[lhuegele]

To clear the DNS cache on the client side:

- open a command prompt
- type ipconfig /flushdns
- Press enter

To clear the DNS cache on the server side:

- From your DNS console on your DNS server, right-click on your server
- One of the options you see should be "clear cache"

Good luck,

 

[dangermouse1977]

OK

technome - have done this, no difference.
we were stable for a couple of hours then it went again.

lhuegle - have done this, both server and workstation - again no difference, it still falls over.

Any further suggestions?

 

[normntwrk]

when you are having the trouble try pinging a known Internet address by the IP address. If you can't ping that you probably have an issue with your router

Norm

 

[dangermouse1977]

When it packed up this morning I tested the following

ping via name - dns resolved, ping failed
ping via IP address - fails
traceroute - route gets to internet router in 1 hop then fails
pathping - ping gets to internet router in 2 hops then fails.
Recursive DNS test passed.

Any further ideas?

 

[technome]

Agree with Norm...
By any chance do you have a second network interface enabled ? If so, and unused, disable it.

Since it is intermittent how do you get it working again?

You router/firewall should be on a UPS. Many router /firewalls have small power supplies, with marginal capacitors for filtering power anomalies or maintaining power during voltage sages.



........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[dangermouse1977]

I do have a second NIC enabled in the machine, this is connected to my network switch (the Internet router is connected to NIC1, the hub to NIC2)

To get it working again, I manually reboot the Internet router.

Said Internet router is connected to a UPS.

Does this help further?

 

[technome]

Norm is likely right, an issue with the router.
Is the firmware up to date on the router? What brand


........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[dangermouse1977]

The router is an i-Direct 3000 satellite internet router, it's managed by the ISP, so there's little I can do to it firmware wise.

The ISP are saying that the reason why my connection stops working is that the number of "sessions" originating from my LAN reaches their max allowed limit and so we're shut off.

This sounds like waffle to me - does it make any sense to you?

 

[technome]

Not dealt with satellite much, as I am in New York City.
From what I have picked up, satellite provider do manage there limited bandwidth. Been on one connection where they just throttle the client's bandwidth down to below dial-up speed after a certain amount of bandwidth use. I see no reason why they can not limit sessions.

........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[dangermouse1977]

Just to update this thread with a resolution in case anyone with the same problem comes searching.

It seems that the problem was due to the fact that our although our Win 2003 server was handling DHCP and NAT duties, the i-direct also still had NAT and DHCP server turned on.

Turned those 2 services off and got the ISP to assign us a static IP address and the system has now been stable for 3 days.

Thanks all for suggestions and help.

 

[virtualsys]

Hi before I've tell something, would like to ask an update. Have tried to figure out between modem and router.

Thanks