Problem with static addresses and my DSL connection

Factual Questions
1

Short version*******

My house has 3 computers connected to a DLS modem. Last night I statically assigned IP addresses to the computer instead of letting my modem/router assign them through DHCP. This caused the computers to lose Internet connectivity. Why?

Long version*******

You’d think that since after my next term in College I’ll be getting a degree in networking, and that next week I’ll be going for my CCNA certificate, that I’d know the answer to this question, but I don’t.

There are three computers in the house all connected to an ActionTec modem/router/switch (We have QWest). For a while now, we keep having Internet connectivity problems where I’ll have to unplug, and then replug the power cord in to get an Internet connection again. For the last couple of days there’s also been the problem of getting an IP address from the router’s DHCP server. Sometimes it would take forever to get an address, and other times we get IP conflicts.

So last night I decide to fix that. I decided to assign fixed IP addresses to the computers to eliminate the DHCP problems. After talking to tech support because I thought that a storm was the cause of our Internet connectivity loss, it turns out that assigning the static IP addresses was the cause.

So, why would that screw up our internet connection?

2

You said you’re getting a degree in networking, so I assume you did this, but on each computer did you set the DNS address to your modem’s address (or a DNS server)?
Cuz if you leave that step out that’ll do it.

3

:smack: I’ll bet that’s it.

4

I made my IP address static again, and this time used the DNS addresses that my router uses. Sure enough, everything seems to be working fine now. :o

5

I’m always surpised windows let’s you get away with not entering that. It ought to at least say “Are you sure, because without that info, you’ll have to look up the IP address yourself—OK/cancel”