According To Jim Warholic

Comcast eSupport Chat Transcript

James > Can I hook up another extra modem on my current system, by just getting an extra IP address and calling my extra modem number into Comcast central?

Allan > Hello James, Thank you for contacting Comcast Live Chat Support. My name is Allan. Please give me one moment to review your information.

Allan > No, you would need to have a second subscription to the Internet service.

Allan > Which would double your monthly rate.

James > Are you sure of this? Because when I talked to the the install guy last year, I thought he said I could do that.

Allan > Yes, I am sure. If you would like to have a second cable modem, you would need to contact our Sales department, and have them create a "second house key", which will allow a second cable modem to connect. This will result in a second charge for the internet service.

Allan > If you simply want to get a second computer connected to the internet, you could set up a home network.

James > OK thanks for that info. What then does other dynamic IP addresses do for you?

Allan > You can use a hub, switch, or router. Use of a hub or switch will require to you purchase a second IP address from us, which is $4.95 per month.

Allan > A properly configured router will not require an additional IP address.

Allan > The additional IP address allows additional computers to get online, when using a hub or switch.

James > I understand that from a router standpoint that I don't need additional IP addresses. So, what is the reason to have more than one IP address? Is it possibly for gaming? When two people want to be hooked up but with unique IP addresses from the same location?

Allan > The Comcast service comes with a single IP address. When your computer is connected directly to the cable modem, that IP address is assigned to the computer. When you have a router connected to the cable modem, the router will receive that IP address, and then the router will assign separate IP addresses to the computers connected to the router. A Hub and a Switch do not have the ability to assign IP addresses. So when you have a hub/switch connected to the cable modem, the single IP address that Comcast provides will allow one computer to get online. You would need to get a second IP address for the second computer.

James > Does having an extra IP address, and hooking up the extra computer through the hub or switch keep the speed to each computer faster than one IP address and using a router?

Allan > There is no significant difference between using a hub, switch or router.

James > OK, that answers my questions. Thanks for the help. Much appreciated.

Allan > You're most welcome.

Allan > Analyst has closed chat and left the room

Thank you Comcast for an excellent and fast response to my questions. I was very impressed with the eSupport Chat Session.

Read the Comcast Home Networking 101 information page.

Read more about installing two or more Comcast Modems at the same location.

Jim Warholic

Business Internet Marketing Solutions

Labels: Comcast, Networking

Can I install more than one Comcast modem at one location?

The simple answer is yes, but it is going to cost you for a second connection.

The following was a submitted question to me.

Message: My wife and I have two rooms with our respective offices. Our house is new and installed with cable TV/Internet cable connections in the walls of each room. My wife's computer is connected to Comcast through a cable modem with a router. Right now I have set up a wireless connection to her computer through a wireless router in her office but the speed is diminished on my computer. The only other way to connect to Comcast through her modem would be to run an ethernet cable through the attic from her router to my office which could be dangerous.

It seems that every Comcast modem has its own unique MAC address. I do have a another Comcast modem the same as my wife's modem which I purchased on EBAY. Is it possible to clone the MAC address on my wife's Comcast Modem into a router in my office and connect the purchased Comcast modem into the cable connection in my office and be able to get on the internet? Thanks

Regards

H.

Answer: Hello H,

What I think you're asking is,

Can I hook up another Comcast modem using the front end of a router, with the cloned address of the other Comcast modem?

First off, you are right, every Comcast modem does have its own unique MAC address.

The router is meant to be on the output of the Comcast modem, not the input of the Comcast modem. Routers make the Comcast modem think that there is just one unique IP address on the output of the modem. But, in actuality, the router routs the information to each computer on the Local Area Network (LAN). The input from Comcast Central goes into the modem from the coax cable, and not the other ethernet cable for the LAN network.

I too have an extra Comcast modem. When I upgraded to digital voice with Comcast, they installed another modem with phone built-in. My original modem was purchased by me at a local store. When the service guys did the install, they had to call in the new modem to Comcast Central.

My understanding is that only one modem of that address can be installed at a time. If you think about it, this makes sense, otherwise the system would not know which modem is handling the information. However, if you want to pay for another Comcast account, I think you can get two Comcast modems hooked up at the same time but with unique MAC addresses. Gamers, who like lots of speed have done this. Comcast then splits the coax cable and runs it into both modems. Then you have two outputs (one from each modem). Note: just as your router assigns a unique IP address to each computer, the Comcast DHCP system assigns an IP address to each modem.

As far as speed is concerned with your current wireless setup, what is your Internet speed with the current setup?

Compare your speed at both computers.

How far is your wireless computer from the office router?

Certainly the best connection is to have a cable going to both computers from the router. Many times the problem with wireless is the location of the router or the location of the antennas on both the computer and the wireless router, and that they are behind shielded walls or just long distances.

So, as it is, I think you have a spare second modem that can only be used if you pay for another hook up.

Read other posting with a conversation with Comcast for additional modem, router, switch, and hub information for a Comcast home networking system.

Jim Warholic

Marketing Solutions

Labels: Comcast, Hardware, Networking

Slow Speed Broadband Connections With Comcast Are Not The Norm

If you are experiencing slow speed broadband problems you may have the following IP problem.

There does seem to be a situation that occurs from time to time with Comcast high speed Internet that is very peculiar. It seems as though some of the IP addresses provided by the automatic DHCP configuration at Comcast produce a very slow Internet connection. Getting a new dynamically generated IP address from the Comcast system can help improve your connection upload and download speeds issue.

Test your Internet speed using any one of the modem speed tests online. Then check your IP address using the check my IP address websites. Write both of these down to use later for comparison purposes.

How do I get a New Comcast IP Address

If you have a router installed after your Comcast modem, then this next procedure is very easy to get the Comcast system to dynamically generate a new IP address. If you do not have a router, I strongly suggest you get one to have an extra firewall between your computer and the Internet. Most IP addresses given out by the Comcast DHCP system are in a leased mode. This means that if your modem is turned off for several days or more, the IP address goes back to a group of IP addresses to be automatically reassigned to other users. Turning off the modem for short periods of time will not reset the leased IP address because the modem is assigned the IP address based on the original computer's MAC address. Every type of networking hardware has a unique code that is the Media Access Control address or MAC address for short.

Router's also have a MAC address. Once this MAC address is synced up with the cable modem, the Comcast DHCP system assigns the IP address to the online outlet. However, if the MAC address is changed, the Comcast DHCP system assigns a new IP address to the online outlet, because it thinks it is a different location. Each computer, with a network card, also has unique MAC addresses. If a person were to hook up a different computer directly to the cable modem, it is likely that a new IP address would be assigned by powering down and then up again the cable modem. However, with a router it is much easier to assign a new MAC address to the router itself. Most routers today have what is referred to as clone the MAC address. This feature allows the user to make the router look like any one of the computers that reside on the premises. Simply logging into the router through a web browser by typing http://192.168.1.1 for Linksys or do a search for Router IP Address to find your particular brand. Then type in the login name and password. Hopefully you changed these for security purposes (and wrote them down) when you installed them from the defaults. This allows you to login and set up the router using the internal configuration program. Find the area where you can clone your MAC address and perform a clone to a new MAC address. Before you clone the MAC address, write it down. This is so you can put it back to the original if you need to. Once the cloning is done, then you can try a release IP address and renew IP address in the router's programming structure. This sends a release the lease to the Comcast DHCP and then renews with a new IP address. Suggest powering down the cable modem, router, and computer at this time. Then re-power everything back up and you should have a new IP address.

Now go back and check to see what your IP address is and the speed at which you can upload and download from the Internet. Hopefully you are now running at light speed.

Good luck.

Jim at online business solutions.

PS This particular problem I have personally seen, and have been able to rectify Internet connection speed issues using this technique. This may not be your particular problem, but it's worth a try. This new IP address solution might also work for other high speed broadband ISP providers.

Labels: Comcast, ISP