Internet Issue

I have an office with a cable connection from an ISP called Optimum Online, with a linksys router with 8 port switch. As you can tell they are a small office, with a an SBS 2003 Server. The internet keeps dropping, and I thought it was the ISP. They swapped out there equipment, and it was still dropping.. So we sawpped out the linksys router, and same thing. I scanned all the machines for a virus and everything is clean.. I have 5 static Ips from the ISP, and If i plug a machine directly to there router, everything works fine. Even the equipment on there network, soon so it goes back into there evnironment it goes back down. I've ran wireshark, and everything looks fine to me.. I'm not sure what to really do, everything looks fine..
Matthew GalianoCTOAsked:
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Is it a specific machine that when removed everything works or any machine?  You could have a NIC card sending out bad packets.  Normally that should show up on wireshark but maybe not.

Also what actually goes down when you loose internet?  Is it just web browsing?  Can you ping by IP address when everything is down?  Just trying to find out if all of the Internet is down or maybe just DNS.
Are you running the cables in the ceiling (above any fluorescent lights) or near any devices that could be causing noise on the line?
Your cabling is below par.  Check the connections at the jacks - the wires should be short or twisted close to the connection.  They should not be long leads extending out from the cable jacket.  Long individual wires can cross-talk and cause dropped connections.

The cable itself should be marked CAT 5, not CAT 3.  

There should be no splices between the station jack and the router.
Since they have an internal SBS running, you likely have a fair bit of internal network action going on as well.  When you have an outage, does the internal network stay running (and is robust, e.g., good transfer rates and response times from the server for example). If the answer to this is "yes" then you can likely rule out a local network card or cabling (on the LAN side).  Your problem most likely exists on the WAN side.  If "no", start checking local machines (either with a network analyzer or simply unplugging machines when the network goes down).
As another poster asked, what is the nature of the failure?  No internet including failure to ping known IP addresses (you want to ping directly to an IP address to eliminate issues with DNS failure).  Have you tried DNS lookups if the pings are working?  Have you attempted traceroutes?  Is your connection simply cable --> Cable Modem+Router --> Linksys Router --> (multiple wired connections) Computers
Matthew GalianoCTOAuthor Commented:
Thanks for the quick response, it was something with the server. What ended up happening was that exchange had spam in the queue and was pumping them out slowly. I cleaned everything up on the network, and exchange queue. It is all good now.. THank you guys for your help...
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