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Partial network couldn't connect to Inte

By wpteh ·
I had a problem with my network recently...7 users cannot surf net overnight. The settings all remains unchanged. I've tried reformatting their PC and reinstall everything, but only 5 of them can resume to surf the net. I've also scan all the PC with the latest virusscan and no virus is found. My network's 3 cisco router is covered by a watchguard connecting to another cisco router before going to Internet. I found out that the PC ping will always stop between the firewall and the router going to the Internet. What could have happen?

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Re: Partial network couldn't connect...

by stoker In reply to Partial network couldn't ...

A little more info about your systems would help you get more useful answers;

-Normal 10/100 Ethernet, utp?
-What kind of OS on the clients? Is it the same on all clients?
-Does every client have a full qualified IP or do you use NAT with private ip ranges?
-3 cisco routers? what kind? how are they connected?
(E.g. Clienst-HUB1/Clients-HUB2 ==> Switch --> Router1-FirewallRouter-Router2-Externalrouter-ISP)
-What kind of lines, T1 etc.
-And why is it routed the way it is?
-Does each router have its own fully qaalified IP?
-Any ipv6 involved? vpn?
-Did you set up the fw yourself? what kind of filetering do you do with it, and also what kind of internet access are you trying to do with the clients?
-If a trace stops within the routers or firewall it is obveious thats where the problem is (?)

12 clients and 3 routers looks strange to me, is it connected to another enterprise dept/building?

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by wpteh In reply to Re: Partial network could ...

Sorry, I left out the details.

1) All 10/100 Ethernet connections. UTP Cat 5.
2) 4 Servers using NT Server 4.0. 80% of the client using NT Workstations nd the rest Windows 95/98.
3) We have around 80 users...only 6 of them couldn't surf the Internet overnight. The rest of the staff is ok. No change in settings on anything.
4) All the problematic PCs lies in different Switches and Hubs.
5) 2 other locations (each with a router) are connected to our router (namely Router A) via 64K leased lines each. And Router A is connected to the Firebox (Watchguard Firewall). The Firebox is in turn link to another router before connected to ISP via a single 64k Leased line.

CISCO Router
WatchGuard FireWall
CISCO Router
/ | CISCO Router | CISCO Router
/ | Location A My Location Location B
(60 Users)
2 switches
2 10BT Hubs

The Firebox is using NAT to the Internet Service Provider. Normally the ISP will give us a pool of IP addresses to connect to them, I wonder if there is a limit in the number of IP addresses in this pool.

I ping the Servers twice (using both NETBIOS name and IP address) using one of the problematic PC and there is a reply. So it means that there is no physcial connection problems.


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