Re: Intermittent intra-LAN connectivity

Tech-Archive recommends: Repair Windows Errors & Optimize Windows Performance

From: serverguy (nospam_at_hatespam.com)
Date: 05/25/04 

Date: Tue, 25 May 2004 10:43:32 -0400

Just for yucks, have you checked the link speed/duplex settings on all the
pcs and ports and forced them to a set speed rather than using Auto?

"Dan Horne" <danDOESNOTLIKESPAM@taisweb.net> wrote in message
news:11fe601c44255$5f642af0$a001280a@phx.gbl...
> Sorry for the long post, but I want to make sure I cover
> everything:
>
> 2 weeks ago, a client began experiencing difficulties
> with their local network. Pinging around inside to the
> other desktops and their server produces strange
> results. The first ping is almost always returned
> immediately, followed by 3 timeouts. If you immediately
> ping again, you get 100% loss. If you wait a few minutes
> and try again, again you will get 1 followed by none.
> This occurs for all computers EXCEPT MAIN SERVER and
> except the gateway. There is a file server that also
> experiences this problem. The clients cannot get files
> off of the server due to connections dropping.
>
> SETUP:
> There are 2 servers (1 W2K3SBE, 1W2K), 5 XP Pro stations,
> 2 Mac desktops and 2 Mac PBooks all running OS X. The
> W2K3 server and the gateway are in our server room, and
> the rest is 15 floors down in their office, connected by
> a single Cat5e cable (they never have a problem
> contacting the server or the gateway, though). The
> clients had a mixture of switches and hubs in their
> office. The gateway is a Cisco PIX 515, and the clients
> are connected to a dedicated interface on that firewall
> and are port-address-translated to a dedicated public
> address.
>
> I HAVE TRIED:
> 1. Replaced all hubs with switches. No change.
> 2. Temporarily replaced all switches with hubs and ran a
> packet sniffer. I saw NO unusual traffic, and not a
> whole lot of it (about what would be expected from such a
> small network).
> 3. Tested the long line for attenuation. Signal is good.
> 4. Only one of the switches is a "smart switch" (the one
> connected to the server and gateway and the long cable),
> but I am seeing no collisions or errors on any port on
> that switch.
> 5. Turned off computers one-at-a-time (including servers)
> to see if any single computer was the source. No change.
> 6. Disconnected switches one-at-a-time to see if any LAN
> segment was responsible. No change on any segment.
> 7. Plugged into different interface on the firewall. No
> change.
>
> OBSERVATIONS:
> 1. The problem began when the firewall began refusing all
> connections for all interfaces and was rebooted. The
> problem does not show up on any other network connected
> to the firewall.
> 2. The clients have a good, fast internet connection
> through the firewall with no packet loss.
> 3. The Mac's seem to be "offline" more than the Windows
> stations, but all of the comps are up-and-down.
>

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