sharing a cable modem, how? a switch?

[KerryrreK]

Okay, I got cable internet recently. So far, dont ask why, but I have my comp hooked up to the modem using the RJ45 port, and my mom is using the USB port for her laptop, BUT, when i get off the net, she has to unplug the modem to reset the IP address so she can use USB, and obviousyl we cant both be on at the same time. This makes her very angry because she never can get it to work (it seems simple, but nothing is to her), so she wants to split the RJ45 connection so we both can use it (not necissarily at the same time).

So I was thinking that I need to buy an 8 port switch (they're only a few $'s more than a 5 port so why not?)and hook up the modem output to one port and my comp on one port and hers on another, right? Then we could use the same IP address and not have to reset the modem?

basically, what hardware do i need, and what software may i need to do this?

Kerry

Okay, now i see that i need a router inestead of a switch? is that right?

[Yakbak]

If your ISP only offers you 1 IP address for your current plan, you can NOT use a switch to share your internet. Only if they have assigned your cable modem 2 or more IP addresses, then a switch would work, giving each computer its own IP address.

In your case, to share 1 IP address, you would need to pick up a router, or use a software-based NAT/proxy solution, such as Microsoft's ICS, Wingate, etc.

[nebben]

It depends on your cable modem. If it is serving private addresses to whatever is connected directly to its ethernet port (10.x.x.x or 192.168.x.x), then you'll be fine with a hub or switch. However, if you are getting your external IP address on the machine that is plugged into it, you'll need a router. A cheap cable/DSL router from linksys, netgear, dlink..etc. will be just fine. They are technically NAT routers, which serve private addresses for the computers in your house, and hold the external IP from your ISP.

Also, unless you're paying for two external addresses, and if your modem doesn't do NAT already, you'll need a router.

-ben

[Edward2]

Yes you need a router. The router will get an internet IP address from your ISP, and both of your computers will get LAN IP addresses from the router. This way both you and your mom can access the internet at the same time.

The cable modem will connect to the WAN port on the router, while both of your computers will connect to 2 of the LAN ports on the router. There really isn't any software setup required, but both of your computers will need NIC cards (RJ-45).

[KerryrreK]

THANKS EVERYONE!

(Im not sure if I have a static IP address, since it supposedly changes when I switch from the RJ45 to the USB connection) will I get a full-duplex connection between my computer and router? Im assuming my ISP connection is half duplex right? I'm new to this duplex thing, but with full duplex on both machines running at the same time what would my connection be like in reference to my current single connection?

she already has a NIC card she bought on the advice of a friend and my wonderful Abit IT7 MAX has built in LAN, so i guess ill get this 3com router off newegg and everything should go nicely. Since it also acts as a switch could I use it to set up a mini-LAN party with 4 other friends?

<---major noob to networking, was also a major noob to hardware 3 months ago, now just a semi-noob though thanks to this site!

Kerry

[Edward2]

It doesn't really matter whether your internet IP address is static or dynamic. Your router will work either way. It will get the IP address from your ISP.

You may have to setup the router for 100 full-duplex on the LAN side... this does not apply to the internet (or WAN) side. Your ISP limits your internet connection speed to whatever they sold you (such as 1Mbps down and 128Kpbs up). Typically you will not notice any difference in internet surfing speed even when both you and your mom on online. The only exception might be if both of you are trying to download large files at the same time.

Yes, you can use your router for LAN parties. It should detect their computers as soon as you connect them to the router. If you setup your router for DHCP on the LAN side, it will assign LAN IP addresses to any computer that is connected to it. The computer's NIC card has to be setup for DHCP also, of course.

[su root]

Originally posted by nebben
It depends on your cable modem. If it is serving private addresses to whatever is connected directly to its ethernet port (10.x.x.x or 192.168.x.x), then you'll be fine with a hub or switch. However, if you are getting your external IP address on the machine that is plugged into it, you'll need a router. A cheap cable/DSL router from linksys, netgear, dlink..etc. will be just fine. They are technically NAT routers, which serve private addresses for the computers in your house, and hold the external IP from your ISP.

Also, unless you're paying for two external addresses, and if your modem doesn't do NAT already, you'll need a router.

-ben

I know of no cable modems that act as a router and perform NAT. Which cable modem were you referring to that does this?

You should always get an external address (unless your ISP is really messed up and trying to rip you off).

[su root]

Originally posted by KerryrreK
THANKS EVERYONE!

(Im not sure if I have a static IP address, since it supposedly changes when I switch from the RJ45 to the USB connection) will I get a full-duplex connection between my computer and router? Im assuming my ISP connection is half duplex right? I'm new to this duplex thing, but with full duplex on both machines running at the same time what would my connection be like in reference to my current single connection?

she already has a NIC card she bought on the advice of a friend and my wonderful Abit IT7 MAX has built in LAN, so i guess ill get this 3com router off newegg and everything should go nicely. Since it also acts as a switch could I use it to set up a mini-LAN party with 4 other friends?

<---major noob to networking, was also a major noob to hardware 3 months ago, now just a semi-noob though thanks to this site!

Kerry

You are getting a dynamic IP address. (you would have to set it if it were static.)

You will get a full duplex connection between the computers that can do 100Mbits and the router. Generally the cable modem will run at 10Mbits half duplex.

Half-Duplex: A computer running Half Duplex can only send or recieve on the cable. 10Mbit is only Half-Duplex (as it uses one pair of wires)
Full Duplex: A computer running Full Duplex can send and recieve at the same time (two pairs of wires used, 2 for transmitting, and 2 for recieving.)

[nebben]

Originally posted by su root


I know of no cable modems that act as a router and perform NAT. Which cable modem were you referring to that does this?

You should always get an external address (unless your ISP is really messed up and trying to rip you off).

I am forgetting my original post already. Oh well. When I first got cable internet access, I hooked my Motorola Surfboard something something up to a hub...I forget which IP addresses I was getting on my two PCs, but I'm 90% sure they weren't private IPs (I am almost certain they were class A ATT addresses), so I assumed the Motorola was doing some kind of routing. I could be way off though....?

-ben

[su root]

no, the modem is just a modem. all it does is connect your home network to the ISP's network. Your ISP's network provides the DHCP, which would give you an external address.