I was "happy" with my dial-up 56K modem internet access, but some accesses were so slow that my family decided that we should try a cable modem.
Basically, and usually on weekends, my dial-up internet connection was so slow that it was totally un-useable. For instance, signing in to a free email account required more than 30 minutes. (Yes, I know that dial-up modems are slow, but that is NOT the problem here.) During non-peak hours, access was instantaneous - maybe 20 seconds. And while some sites never loaded, other sites were still available at the same speed as before.
At any rate, my family decided that we should try a cable modem.
Comcast was the only high speed internet option (Northern Virginia).
The sales person said that all we needed was a Cable Modem and that it would support up to 4 computers. Well, that was wrong - you can only plug in one computer. If you want to support more, you must provide some form of address translation.
Each computer on your network has its own IP address. The Cable Modem has 2 IP addresses - one for your network and the second to talk to your cable provider. The address translator converts a local network address to the internet address so that only the internet address is seen to the outside world.
This can be accomplished using one of the following.
This is great - This is good - This beats DSLI wanted
Recently, Comcast was bought out by AT&T - so I tried their web site. Another waste of time with no useful information.
I guess persistence counts - I eventually found a list of supported cable modems (it was under FAQs).
Well, I finally got some answers at www.comcastonline.com - you would think that the original comcast page would have a link to here. Instead, I had to read most of the FAQs to find it. ($55/month)
I can not determine if there is an extra charge for a fixed IP address.
There are basically 2 ways to provide address translation
www.howstuffworks.com provides a very good description of address translation (NAT).
Windows XP SMC EZ Card 10/100 PCI (SMC 1211 Series) Linksys Cable Modem with RJ45 and USB capability The XP system was already connected to a network that accessed the internet via a dialup modem on another machine
Adding a Cable Modem
Oh, the cable modem could see the internet ok (verified using ipconfig and the modem's lights), but Internet Explorer and ping could not.
The cable modem was plugged into the USB port, and I had the computer connected to a local network with a network card (NIC). I could see the local network fine, but not the internet.
After several hours of work, I found that when I disabled the network card (via the control panel), Internet Explorer and ping accessed the internet without problems ... but I could no longer see the computers on the network.
The solution was to enable ICS (Internet Connection Sharing).
When ICS (Internet Connection Sharing) is enabled, XP tries to set the network card to 192.168.0.1 - there are no options, that is the only possible address.
Well, the existing network shared the internet through a dialup modem on another computer which already had that address. My plan was to leave the system with the modem at that address and to give the XP NIC another address. (I want to keep the dialup connection so that I could still have internet access when the cable system is not available.) You guessed it, I had to change the other computer's address.
After ICS was enable, all the computers on the local network were able to use the cable connection to access the internet and the XP system was able to see the local machines.
Cost - about 6 hours, 11 counting additional research and testing after it "worked".
Allowing for Christmas and several snow storms - 2 months is still too long.
About a month ago, we added a router to the network and removed the Windows XP machine from the path (we originally used it as the router, but it hangs on a regular basis and would keep the other machines from reaching the internet).
After 2 days of trouble shooting and/or waiting for the problem to fix itself, I called Comcast (the ISP). They flatly refused to talk to me - telnet is not handled by their technical support. I tried their "live chat" support, and they said that Microsoft would have to solve the problem. Specifically, they "were not licenced to support third part software".
I called Linksys (the cable modem manufacturer) - they said that as long as http, ftp, and pop3 were working, there was no way that the modem could be the problem - it just passes the packets, it does not contain a firewall or any kind of filtering capability.
I tried PortQry.exe to test port 23 (telnet)
C:\DOWNLO~1\PORTQRY\EXE>portqry -n cpcug.org -e 23 Querying target system called: cpcug.org Attempting to resolve name to IP address... Name resolved to 22.214.171.124 TCP port 23 (telnet service): LISTENINGSo that's not the problem.
Princeton terminates telnet sessions in this manner for security reasons if the IP address is not properly registered.
8 hours later, it fixed itself.
My best guess is that is was the cable company's problem.
Of course, there is another possibility - another computer could have sent intentional disconnect messages to my system.
On your Windows XP system, look at
%SystemRoot%\System32\Drivers\etc\Servicesto see which ports are mapped to which services.