[hardcat1970]

I'm using road runner cable modem service. I ordered second ip address, it was assigned with DHCP, from them for about a year. So basically i have 2 ip set up like:

24.17.16.17
24.17.16.18

but they are dynamics.

now i want to add a router just to share the second ip address which is 24.17.16.18, is it possible?

[aaanorton]

Just out of curiosity, why pay for two IPs when you can share one just as easy and save the monthly fee?
I don't see any reason why not, though. How is it physically set up now?

[hardcat1970]

Originally posted by aaanorton:
Just out of curiosity, why pay for two IPs when you can share one just as easy and save the monthly fee?
I don't see any reason why not, though. How is it physically set up now?

first of all, i don't want to share my connection because i need a dedicated line for my work. Second, it costs 5 bucks monthly, so it is 60 bucks a year. A router costs more than that a few years ago, so i figured out what the heck.

The set up basically is the cable modem plugged into a hub, one for my b/w g3 and the other one is my airport base station, but they are totally 2 different ip addresses, and different routers where i look up in tcp/ip.

[aaanorton]

Wow, so you're getting broadband to two different addresses for just the cost of a 2nd IP. I'd say that's pretty great.
Anyway, get a router now. They're dirt cheap, even the wireless units, if that's an issue. This is what routers are for. It takes one IP and shares it invisibly (to the ISP) with a number of computers. No problem.

[Rainy Day]

now i want to add a router just to share the second ip address which is 24.17.16.18, is it possible?

Depends on the router. Most will do it. The SOHOware BroadGuard can do it. It can act as both a DHCP client and a DHCP server. But it can also answer to a fixed IP address.

Most modern routers, such as the BroadGuard, can be configured in much the same way your Mac can. As far as the cable modem is concerned, a router is just another computer. The difference is that 256 computers may be sitting behind this router, all transparently sharing the same IP address.

first of all, i don't want to share my connection because i need a dedicated line for my work.

I think you may misunderstand what you have. From the sounds of it, you don't have a dedicated line for your work use. All you have is a dedicated IP address. Unless you're running some kind of server, you probably don't even need a dedicated IP address for your work computer. But since most cable companies do not allow servers on their lines, i doubt that is the case for you. You didn't mention a VPN, so i'm guessing you don't have that.

Second, it costs 5 bucks monthly, so it is 60 bucks a year. A router costs more than that a few years ago, so i figured out what the heck.

What you're getting for $5/month is not added bandwidth, only another IP address (which you can get from any router). It's pretty much a rip-off since routers are so cheap anymore. I think the BroadGuard is now selling for $59, and it comes complete with a hardware firewall! (Hardware firewalls offer much better protection than software firewalls).

Everything connected to your cable modem is sharing the same pipe. In fact, not only are all the computers behind your cable modem sharing the same pipe, you're sharing that pipe with all your neighbors as well! A cable broadband connection is very much like a typical municipal water delivery system. From your local water tower (ISP) comes a big ol' water main. It branches off down various streets. Along the way, each house reaches out and taps into the main. Water pressure is pretty good, so long as everyone doesn't have their taps turned on all at once. If a bunch of your neighbors are watering their lawns, running their dishwashers and washing machines, taking showers, flushing their toilets and brushing their teeth all at the same time, you may notice a drop in water pressure. So too with cable. DSL is somewhat different. It is like having your own separate pipes all the way to that communal water tower (ISP/InterNet). Water pressure is now dependent on how full the water tank is, but independent of what your neighbors are doing.

The set up basically is the cable modem plugged into a hub, one for my b/w g3 and the other one is my airport base station, but they are totally 2 different ip addresses, and different routers where i look up in tcp/ip.

Even with multiple IP addresses, all computers connected to this cable modem are sharing a single pipe; they're competing for the same fixed bandwidth through that pipe. You do not have two broadband connections. You are merely paying more for the additional IP address, which your own router can give you just as easily without the $5 monthly charge. Most likely you'd be better off sharing your work and personal computers via a single router such as the BroadGuard and dumping the additional $5/month charge you're now paying. But i'd tell your cable company you got rid of the second computer, rather than tell them you bought a router. Some seem to think they have a god given right to charge you for every computer you have in your house. That's like the water company charging you $5/month for each toilet you have.

[hardcat1970]

Originally posted by Rainy Day:

Thank you so much for your input. I got crushed by posting this question on the lounge, someone asked me if i stole an ip, what a joke. But your answer is what i want all along.

Anyway, i bought the router last week and everything went smoothly.

The reason I asked this stupid question is that i have an dynamic ip on my b/w g3, even though it was an dynamic ip, but it has not changed in 4 months, and i am running my little webserver and connecting to one of my friend's secure hl server, so i don't want to mess it up plus i am too lazy to configure a router.

And i bought an Axis network cam, which it doesn't require a pc. The problem is that it needs a static-ip. I thought i could hooked it up to my other ip, which was connected to the base station and share this connection. But it didn't work, so i bought the router and it all figured out.

I guess now i could save my $5.00 for this additional ip. That's why i am so upset someone thought i stole an ip because i was trying to be honest with my isp by paying them $5 extra a month.

[Rainy Day]

You're welcome; glad i could be of service.

even though it was an dynamic ip, but it has not changed in 4 months

Sometimes those cable IP's don't change very often. If you lose power to your cable modem, however, it'll probably change. Also, they could change their policy (i.e. configuration) and in the future, your IP address might change more frequently.

I am running my little webserver

Just be aware that it is most likely a violation of your Comcast subsriber agreement to run a server of any kind on their line, and if they find out, they may pull the plug on you (or want to charge you BIG $$$ for a commercial account, if available in your area). This is why i dropped my cable and went with DSL (i wanted to run a server). YMMV.

And i bought an Axis network cam, which it doesn't require a pc. The problem is that it needs a static-ip.

I assume the cam doesn't understand DHCP and thus requires a static IP for whatever it's talking to (e.g. your router), but on the other end of your router, you should be able to use a dynamic IP. Of course that may make locating the cam a challenge (from the outside), but since your dynamic IP doesn't change much, that may not be a problem.