a wired way to get multiple dynamic ip for two nic

[rio]

Hi there

I have two nic. Only the 1st nic is directly connected to ISP which grant dynamic ip. I want to use the 2nd nic to get the dynamic ip from isp via the 1st nic which is configured to be a routable nic or being set as a gateway, so that the 2nd nic can connect to ISP to get the dynamic ip.

Is it possible to do so?

Any comment/advice is appreciated.

 

[mikesgroovin]

Yes, this is possible if I understand what you are saying. People do this all the time, in lieu of a hardware router/gateway. Essentially, you are using your PC with 2 NICs as the gateway. You have to setup your 2nd NIC so that it sees the 1st NIC as a gateway. And the 2nd should be static, but as long as it has the internal address of the second as a gateway, then you should be able to see the 'net' with the sencond.

-Michael

 

[rio]

Hi Michael

But if the 2nd nic has been set a static ip, how can this 2nd nic get a dynamic ip via the 1st nic? I want to get a dynamic ip for the 2nd nic. Is it possible?

Rio

 

[mikesgroovin]

Yes, but you have to setup your machine to be a DHCP server.
What type of address did you want for your second NIC. You are going to find that the addresses for the 2 NICs are going to be slightly different.

Did you want to distribute the internet connection into a LAN?

-Michael

 

[rio]

Say, my dynamic ip of 1st nic is 218.x.x.x. I want to use my 2nd nic to act as another computer connecting to the isp directly to get the 2nd dynamic ip like 218.x.x.x. If I have my 2nd nic a static ip, how can I set this 2nd nic to get a dynamic ip? What do you mean to setup my own machine to be a DHCP srv? Did I misunderstand anything? Pls advice.

Rio

 

[mikesgroovin]

Sorry, didn't mean to confuse you.....
But it sounded like you wanted to distribute the connection to your ISP to other computers on the same local network.
The second NIC is not going to be able to receive a dynamic address DIRECTLY from your ISP. However, there is a way to connect this 2nd NIC to a hub/switch and connect other computers to the same hub/switch and ALL have access to the same internet connection that is provided by your 1st NIC.

-Michael

 

[rio]

Well, I've just tried setting up my 2nd nic to have gateway = 1st nic, and a static ip is similar to 1st nic, and two dns = 1st nic's dns. I think the 2nd nic can go out via 1st nic, but it can't reach Internet, can it? I'm not going connect to anyone who's connecting to the same hub/switch, but I mainly want the 2nd nic to connecting out to the Internet. As I know, Isp offer dynamic ip to user by identifying different nic hardware address, doesn't it? That's why I've such an idea to use my 2nd nic to get another dynamic ip. Is it possible to do so?

 

[CrashAbbott]

what you are trying to do is essentially correct however, there is and understanding issue of networking here,,, lets see if we can clear this up,,,

Mike is right on the NIC issues,,

First,, your ISP will provide you with only ONE external IP address unless you PAY for more,,,

So what you have done is called MULTI-HOMING a PC = 2 NICS

the FIRST NIC will get the EXTERNAL IP from the ISP provider,, that is your 218.x.x.x number that you spoke about,,

on the SECOND NIC,, YOU give it a PRIVATE IP (usually 192.168.1.x and so on...)

You put the IP on the SECOND NIC,, and the SUBNET MASK,, (255.255.0.0) and then LEAVE the GATEWAY BLANK,, this NIC will look to your FIRST NIC as the gateway to the world,,

Now, get a HUB,,and connect that to the second NIC,, now every PC that you plug into the hub must have a NIC,,

Make STATIC IP addresses for every PC,, BUT keep them in the same neighbourhood,,

First NIC IP = ISP provider

Second NIC IP = 192.168.1.1 Subnet Mask = 255.255.0.0 gateway=BLANK

connect hub to SECOND NIC,, then attach PC,,

1st PC NIC= 192.168.1.2 Subnet Mask = 255.255.0.0 gateway=192.168.1.1

2nd PC NIC= 192.168.1.3 subnet mask=255.255.0.0 gateway=192.168.1.1

and so on,,,

cheers,

 

[rio]

Hi Crash Abbott, thanks for the detailed advice, but it's not related to my question. Maybe I need to clearly state it once again.

Scenario:
- only 1 PC (no more 2nd pc)
- 2 nic existed in this only PC (is a multihomed)
- no hub/switch in my LAN (not going to share with other PC)
- total two dynamic ip can be got from my ISP if I have 2 PC individually connecting to ISP (I've tried before)

I've got a dynamic ip from my 1st nic. I want to get another dynamic ip for my 2nd nic which gets it by way of 1st nic, so that my pc have two dynamic ip which is my purpose. Could this be done?

Rio

 

[mikesgroovin]

LOL.....funny situation, but no, it cannot be done unless you have TWO connections to your ISP coming into your home/office by way of two modems.

The only reason I laugh is because I don't understand WHY you would want to do this.

-Michael