posted on Dec, 2 2007 @ 11:45 AM
I run a small ISP- so I'm a bit familiar with how systems work for Comcast, AT&T, whoever...
Following the previous suggestions in this thread is an awesome start to figuring out your issue- however I'm inclined to believe that your area's
Comcast service is having problems with their DNS service.
DNS (Domain Name Service) is the server that changes "www.whatever.com" to an IP address the computer can understand. Many DNS servers are attacked
for various reasons and also are subject to heavy loads at times, and cable internet is notorious for bandwidth issues due to the cable infrastructure
which limits the amount of possible data thru an amplified cable assembly which supports an entire neighborhood (you'll see these amps on the cable
lines outside on the poles).
In my experience, cable companies are usually great at providing video, but generally lack the proper technical knowledge to support data services.
Video feeds are simple- they only go one way, but internet data is full-duplex -meaning that data flows both ways- so there are multiple frequencies
being used through the cable to provide that flow, and many many many amplifiers and junctions and splitters and whatnot in the path to your house,
all working together to provide you with crappy data service.
Back to the DNS server- if you noticed with the ping command from the previous posts, it will tell you what the IP address is of any site you enter.
Record the IP address of a few sites you frequent and keep them handy for the next time your service goes down. Once it is down, try 'pinging' the
list of IP addresses you've kept. If you are getting a response with a ping but nothing will load on the browser, you can try entering the ip
address into the address bar on your browser. If the page loads with the IP but not www.whatever.com, then their dns service is down and the reason
you cannot connect.
However, if you are running a ping with the -t in it, and you start dropping requests when the service goes out, then there is a problem with the
actual connection to their network and the tech should be called WHEN it is happening or write the time down so they can check their logs (which any
decent ISP should have available)
Hope this helps- good luck!