Major problems! Internet down, but can ping! WTF!

Winchester

Diamond Member
Jan 21, 2003
4,965
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I am trying to get our internet back up full time.

Diag= Internet <->DSL modem / 8prt router <-> Router <-> 4 Switches <-> 100+ Computers

I have this computer connected to the back of the DSL Modem/Router and I am able to continuiously ping an outside IP address between 4 and 16ms (this morning is was almost all 4ms, now it is getting up into the 20s-200s sometimes, when it is just me and the cable modem, even when the internet is not working (IExplorer). This occurs even when I disconnect everything but me from the modem. The internet will work sometimes for up to 20 minutes and then cut off, even when I never change a thing.

I noticed two servers that had the nachi.worm this morning, but have ran stinger program to remove it from them. Now the file server and email server work fine when I am connected to them. (they were slow until I ran the stinger program)

Our DSL company says it is a computer on our network, since I am able to ping outside, so that it is our problem and they cant help. They said supposedly there is one computer on our network taking up all the network resources. I have yet to find it if so. (are there any programs that I can use to tell which computer on the network is doing this, so I can isolate it?) I would believe the DSL company a lot more if the internet would work 100% of the time when it was just ( computer <-> DSL modem <-> internet) but it doesnt, I am currently in a "window" that I can get on the internet.

When the Internet is up I have went through connecting the switches one by one until the internet quits working, but it works fine with everything connected sometimes, and sometimes not at all.

When the internet is not working, and I click IExplorer, it goes to Website Found, then says "redirecting" for a split second and then just sits looking into space.

The computers should connect directly to the internet when on the network.

EDIT: when I turned off all the switches, routers, and the modem and then turned them back on, everything works for a bit, then off again, not yet though


I need a program that I can use to determine which computer is taking up all the bandwidth, or any other program that might help with this


Can anyone help me?
 

mrbass

Senior member
Sep 13, 2001
773
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We have this problem at our company. One laptop infected with Welchia can take down our watchguard firebox 1000(freeze it) within 1 to 2 mins. Basically I just look at the firewall monitor/logs and see which one is pinging us 100 times a second. Anyway I disabled ICMP packets and only allow it for those who authenticate on our network via a java applet. I'd try to monitor your router or switches and track down the ip that is doing a ton of network activity.
 

AnyMal

Lifer
Nov 21, 2001
15,780
0
76
I am going to take a guess, but if you're able to ping remote hosts the problem may be with DNS resolutions. Have you tried rebuilding HOSTS? Maybe a simple ipconfig /flushdns?