Re: Internet Connection Issues, clients...
- From: Joe <joe@xxxxxxxxxxxxxx>
- Date: Mon, 30 Jun 2008 22:26:57 +0100
JT wrote:
"Joe" wrote:
JT wrote:I have a computer connecting to our server/domain controller, accessing Exchange, Access and other network related applications. All work without a problem.To know what is stopping access, we need to know what hardware and software obstacles an Internet connection has to negotiate. What stands between the workstations and the Internet?
As of recently, 2 computers on our network will not connect to the web. They obtains an IP address via the DHCP (internal) server and DNS (internal) with no issues but still can't connect to the web. When I try pining external domains or ip addresses, it times out. I've tried repairing the IP, flushing the DNS, stripping all startup items, manually entering the ip address and DNS server address and switched it back to auto since that didn't resolve the issue. I've searched and can't find a solution. I thought maybe it could be the server but the server is functioning fine and serving 23 other users who are connecting through it's DHCP and DNS servers. We're using W2K3 SBS.
Short of re-installing Windows XP on the work station, is there any other things I could try before going to that extreme?
Thank you!
In other words, the usual: are you using one NIC or two, if two, are you using ISA, is there a router...?
> One NIC on the server. The work station obtains it's DHCP lease from the SBS
> server and SBS server is managing DNS. We have a firewall router (Netgear)
> connected to a T1 line going out.
So we can pretty much forget the SBS. As long as the client gets the IP address and gateway it should work, at least at the IP address level. We can forget DNS for the moment. Apart from OS corruption, unlikely in two machines simultaneously, that leaves more obscure stuff. The fact that two machines are doing it would seem to alter the probabilities of various kinds of faults, but coincidences do actually happen in real life. Still, the common features of the network are the first things to go for:
Router hardware and internal connection tables. OK, it shouldn't discriminate against just two out of 25 machines, but then this shouldn't be happening at all. If the workstations can ping the router, and see its web management interface, but not see the Internet, it's a good suspect. If you haven't already, try rebooting it, by power cycle rather than software. While the OS code in Netgear routers is pretty reliable, I'm not impressed by their system firmware and fault resilience.
Switch/hub and cabling, switch table corruption. Not all that likely, but again, reboot the switch. If at least one of the workstations is physically close enough e.g. in the same office, and the router has a spare port, try running a cable directly between them. If not, and nothing else helps, it might be worth pulling the router and one workstation cable from the main switch, and linking them with a small switch.
NICs and drivers on the offending workstations. See if there are more recent drivers. Difficult to test a NIC without substitution, but unlikely for two to fail at once. Old drivers are a possibility, or even newly upgraded ones. Here's a way for two similar machines to fail together, after a Windows or driver update.
Multiple copies of the same IP address. SBS usually spots that quickly if it's handling DHCP, but it's worth considering. Not very likely, but you may end up clutching at straws.
Other troubleshooting possibilities are to connect a different computer at one of the offending locations, or to boot up a live-CD Linux on one of them, but it's easy to be misled by apparently clear-cut results when doing this kind of thing. More things are being changed and tested than you realise, right down to the cable leaving the RJ-45 at a different angle...
There are probably many other possibilities as well, but this selection reflects my experience of odd problems. Please post back when you do sort this one out.
.
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