Internet Problem

[karldenton]

Hello,

 

Just recently, we have had a weird internet glitch. When a user logs on and opens the internet, it seems to take ages to display the home page, then you get a 404. If you then imediately try again it works. The problem doesn't occur again until they log off.

 

We are running a ContentCache box, which the computers use as the proxy. There isn't anything on the logs in there.

 

From there is the ISP's firewall.

 

It just seems like it taking ages to authenticate on somewhere.

 

Any ideas?

 

Thanks

 

Karl

[ezzauk]

Have you checked you dns / forwarder settings, it could be a routing problem. also check see if the computer is picking up all the settings off dhcp.

[Michael]

Can you tell us what your home page is? You could experiment and set it as Google or Yahoo.com which are very reliable. I've seen this behaviour before, and in the end it was a load problem with the servers that were hosting the site!

 

To verify your workstation config, type

ipconfig /all

from a command prompt. You should see (at the very least) your primary DNS which should be your domain controller.

[karldenton]

Doing IPconfig reveals as expected, DNS set to dc.

 

Home page is St John's Catholic School for the Deaf Online Learning.

[ezzauk]

Doing IPconfig reveals as expected, DNS set to dc.

 

Home page is St John's Catholic School for the Deaf Online Learning.

 

what about your dns forwards?

[strawberry]

sounds like what you get when you have a toolbar installed. It wont let you view anythign while it loads then once it's on you can see what you want. The 404 will appear moments before it begins to work.

[karldenton]

ezzauk, the dns forwards on the content cache is set to Redstone ISP, 193.164.99.83 and 193.164.97.11

 

Karl

[karldenton]

forgot to add, does do it more when google toolbar is installed. I don't have the toolbar on my machine and rarely have a problem.

[Apathy]

I had a similar problem last year. I found that the home page was being cached by the proxy. Some users got on straight away, some didn't. It was down to the proxy not being able to handle multiple requests at the same time for the same page.

[karldenton]

Still not managed to solve this one either. Seems to do it when joined to domain even without toolbars installed. Could it be do to with permissions, IE trying to update itself?

THanks

[Bodsworth]

same as we get here at college, same error its to do with the DNS, but i dont think the tech staff know how to fix it. It also does it on random websites sometimes too, kind of an annoying problem to say the least.

[karldenton]

Anyone any ideas what could be the DNS fault / solution if it is DNS?

Thanks

[Michael]

Your primary DNS should be your DC and secondary should be your ISP. It could be that your host is suffering from DNS issues. Presumably everything within your LAN is working correctly? If so, it would appear it's an external DNS issue.

 

I have to say St John's Catholic School for the Deaf Online Learning. took a while to load for me. It might be machines are timing out at busy times?

[karldenton]

Just been on to our isp and they suggest its an internal dns issue.

 

The client pc's are set up to obtain dns automatically. The DC has dns set to the proxy server (primary), and the router (secondary). Both the router and the proxy server are then set to the ISP DNS's of 212.44.55.100 & 193.164.97.35.

 

Thanks

[cookie_monster]

Have you tried Wireshark to see what's happening when the browser is pausing?

 

What software is the cache box running?

 

How do you set your proxy settings, group policy? Check to see if 'Automatically detect settings' is checked in LAN settings if it is try unchecking it.

[karldenton]

Thanks cookie_monster.

If i untick the "Automatically detect settings" it goes out straight away.

Is there any way of disabling in GP?

THanks

[cookie_monster]

Yes i think you can set it in Internet Explorer maintenance - Connection - Auto Browser Config

[karldenton]

Finally found a solution to this. Thought it was the "Automatically detect settings" but it wasn't. In the end it was that the tick box "Automatically check if IE is the default broswer" was ticked. Unticked that and it works fine.

Thanks for your help.

[karldenton]

Grrr, thought i'd found the solution but don't seem to have. Wors for administrator but not pupils or staff.?

[Michael]

There is a policy you can enable:

 

User Config > Admin Templates > Windows Components > Internet Explorer

 

Disable changing default browser check

[karldenton]

Thanks, tried that but still the same.

 

Thought i'd give Wireshark a go.

 

2 results are shown below in this post, one is staff one is administrator. All the ip's 192.168.42.* are on the local network, all the rest including 192.168.192.1 are external at redstone4schools. On the staff one there is a black line that says communication administratively filtered. Would like to know if thats local or at isp.

Thanks

[SYNACK]

Thanks, tried that but still the same.

 

Thought i'd give Wireshark a go.

 

2 results are shown below in this post, one is staff one is administrator. All the ip's 192.168.42.* are on the local network, all the rest including 192.168.192.1 are external at redstone4schools. On the staff one there is a black line that says communication administratively filtered. Would like to know if thats local or at isp.

Thanks

 

 

ICMP is ping type traffic. It looks like it can't ping that destination, either because ICMP is blocked by your gateway or to that specific host.

[karldenton]

Thanks, so its probably worth contacting isp as its a managed router from them?

[SYNACK]

Thanks, so its probably worth contacting isp as its a managed router from them?

 

Could be worth having a chat with them telling them about your problem and also giving them the information about the ICMP packet. They should be able to re-enable ICMP requests on the routers internal interface even if they still restrict it outside your local network.

Edited August 1, 2008 by SYNACK

[karldenton]

Ok, spoke with Isp and they say that ICMP been blocked has nothing to do with the delay. They say "The only thing I can think of is that the proxy settings are being overridden and turned off until the initial page loads (or does not in this case). We have seen similar strange issues in the past with browser plugins/add-ons, some of which are malicious. I would suggest checking what add-ons are running in IE (Tools>manage Add-Ons in IE7) and disabling them to see if that makes a difference."

Have disabled add-ons but still the same.

Me thinks there might be a wrong proxy setting in a registry somewhere thats been copied from an old default profile. Might write a vb script to set the correct proxy on log on and give that a go ! Any other suggestions?