Switch Question

thisisalex02

sup all? Well im a little confused. I know a hub forwards data to all the ports and a switch forwards it to a specific comp by learning their mac. so do switches have a dhcp server liek routers, or whats up. if i plug my modem into the switch, and my comp into the switch, what kind of ip should i be getting..lan ip or what? I know how it all connects together just dont know the theory behind it, any suggestions will be appreciated!

/usr

Switches do not have a DHCP server. Think of them as intelligent hubs whos purpose is to decrease network traffic.

I assume you're referring to a DSL or cable modem, correct? If you run a cable from your modem to switch, then plug your pc's up via the switch, you'll get an IP from the modem/router's DHCP pool.

thisisalex02

so if i were to plug in my cable modem to my switch i could only connect one computer cause my modem only provides one ip ? ? therfore a switch is only of use when i have a dhcp server running to decrease network traffic?

/usr

No...

For example, I have a DSL modem at my home which I have at least 4 pc's hooked up to constantly. Even though verizon provides me with one IP address (The IP of my modem/router), all of my clients can connect to the internet because my router will perform NAT.

In short, all my clients get private a private IP from the DHCP pool I specify in my routers configuration.


Go here and get this sites Technotes. They are an excellent study resource and I'm certain they contain information on NAT.

http://www.techexams.net/technotes/networkplus/pdf.shtml

Jerz

thisisalex02 wrote:

so if i were to plug in my cable modem to my switch

Actually, I would connect to your cable modem to a router first and then connect the router to the switch and let your router do the dhcp stuff. OR use your computer for the router and put two nics in it; one plugged into to cable modem and the other plugged into the switch. If you use your computer as a router you could use ics (internet connection sharing), nat or dhcp, depending on your windows flavor.

Jerz

remyforbes777

You are right, if you are plugging your cable modem into your switch without a dhcp server present on your Lan, you would have to get an IP address leased to you by your ISP. So if your ISP is only giving you one IP then only one computer is going to be able to connect unless your switch is able to do NAT. Switches are layer 2 devices and they deal with MAC addressing. Routers are layer 3 and they are able to deal with routing traffic from your lan to another lan. I think there are layer three switches that exist though.

netcom2000

I use a multihomed system (two NIC's) into a machine running 2000 Server, one getting IP from ISP externally,into cable modem, and the other card connects to switch, with statically assigned IP's to other clients, sometimes I run NT4 server on local network providing DHCP for clients, for Internet service for clients I run ICS (Internet connection sharing) on the server.