Big server problems. Any ideas?

[boomam]

Hi.

I got in work this morning early so i could boot everything (power was off over half term).

After boot up of everything i noticed that the internet wasnt working, so after so faffing around between me, our VLE helpdesk(proxying goes through frogbox) and our LEA we finally got everything half working, by changing the DNS forwarding on our DC to the address of our proxy.

Anyway, 10mins later, everything goes belly up. No-one can log on, see their areas if they can, and policys not setting.

I changed the DNS forwarding settings on the DC back to what they were originally, and everything appeared to work again, with the internet returning about 10-15mins later for whatever reason.

 

The problem ive got now though, is that although everything does work, its very slow.

Pinging the DC, which usually averages 0ms, is now averaging 4ms, and log ons take between 5 & 10 minutes to do.

Plus, even using it locally is jerky, as is logging on remotely to it?

 

 

Does anyone have any idea what might be causing this?

 

Thanks in advance all. .

Edited February 18, 2008 by boomam

[fafster]

How busy is the network interface on the DC? Are you pinging the DC via ip or hostname?

[boomam]

How busy is the network interface on the DC? Are you pinging the DC via ip or hostname?

Under 10% most of the time.

Pinging via both.

 

Touch wood, it appears to have sped up, pinging, to what it was before.

Logins are still slow for some clients, but i think thats because they havnt been restarted since the DNS change on the DC. Correct?

[Ric_]

The DNS settings on your DCs MUST NOT point to a remote DNS server. There is important stuff in your DNS that makes things on your network work.

 

If you have brought things up in the wrong order (e.g. DNS wasn't there when certain services attempted to start) then this kind of thing can happen. Your event logs should be able to tell you in more detail.

[greenfieldsupport]

This happens when DNS isnt set up correctly.

 

It will sit there logging in saying "loading your personal settings"... but with no HD or network activity.

 

Id check your DNS, all your local clients should send requests to your domain controllers. Check the domain controllers are listed correctly in the DNS namespace. Make sure they have A records and SV Records.

 

Make sure the domain controllers are authoritative for their domains. Make sure that your domain controllers have a correctly working upstream dns server (although this wouldnt effect your logon times, just your internet access)

 

Also finally, turn off and on all of your switches which are close to your domain controllers, there may just be a problem with them.

 

You have to remember that when you start up a switch it will generate a mass of network traffic for the next 10 mins or so till it gets its ARP cache filled again.

 

Finally use a network analyzing protocol such as wire shark to find out whats really happening. You may be experiencing broadcast storms?

 

From the sounds of it though.. DNS is the place to look!.

 

Hope this helps

 

-Tony

Edited February 18, 2008 by greenfieldsupport

[boomam]

This happens when DNS isnt set up correctly.

 

It will sit there logging in saying "loading your personal settings"... but with no HD or network activity.

 

Id check your DNS, all your local clients should send requests to your domain controllers. Check the domain controllers are listed correctly in the DNS namespace. Make sure they have A records and SV Records.

 

Make sure the domain controllers are authoritative for their domains. Make sure that your domain controllers have a correctly working upstream dns server (although this wouldnt effect your logon times, just your internet access)

 

Also finally, turn off and on all of your switches which are close to your domain controllers, there may just be a problem with them.

 

You have to remember that when you start up a switch it will generate a mass of network traffic for the next 10 mins or so till it gets its ARP cache filled again.

 

Finally use a network analyzing protocol such as wire shark to find out whats really happening. You may be experiencing broadcast storms?

 

From the sounds of it though.. DNS is the place to look!.

 

Hope this helps

 

-Tony

 

How do i check the name space.

The error you listed is very reminicient of the problem im having here.

[greenfieldsupport]

Do you assign your DNS address using DHCP?

 

if not,

 

have you recently changed the ip address of your DNS server / DC?

 

and 2 secs i'll step by step it for you

[boomam]

Not sure how you mean on the first.

 

And the second one no, the DC/DNS server has allways had its IP the same.

[greenfieldsupport]

Start > control panel > administrive tools > DNS.

 

Click the + next to your server name. click Forward lookup zones > click your domain name.

 

Ours is Greenfield.local

 

you should see entries for your clients (A Records) and entries for your name servers at the top.

 

on the left tree, click _tcp.

 

You should see the SRV records for your domain, make sure all your domain controllers are listed correctly there, especially the _Kerberos and _ldap entries.

 

If these are fine, then the only thing you have to worry about is ensuring your clients are pointing at your DNS servers for resolution. like Ric said, your clients should Never be pointing at a remote DNS (like a proxy or worse an adsl router of some kind ). ((Unless your in a very small environment with < 15 machines. )) If they are then it wont do any damage, but you will have to point them back at your local DNS server.

 

You can change it with DHCP if you use it.

[greenfieldsupport]

Not sure how you mean on the first.

 

And the second one no, the DC/DNS server has allways had its IP the same.

 

Okay good

 

on the first one, i'll try ask in a differnt way, does your servers give the clients ip addresses automatically, or do you type the ip addresses manually into each client.

[boomam]

They use DHCP for the IPs.

I do have some on reservations, and our WiFi on manual IPs though.

[greenfieldsupport]

Thats good,

 

thats the way it should be really .

 

Are you sure all your clients are set to use your local dns server as there "primary dns server"?

[boomam]

With the local DNS being the DC?

Yes, as thats whats set on the DC.

 

I did have to change the DNS forwarders earlyier on the DC for the previously mentioned reason, but i changed it back.

 

Touch wood, it appears to be working now.

 

We'll soon see come tomorrow, as thats when everything is guaranteed a restart.