Connect dual NIC using one cable... possible?

By bestbuy
in Smart Home, Network & Security

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Grand Master

majortom1981

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Hi guys,

I've been googling for ages. NIC#1 is connected normally through a cable, with IP assigned by DHCP server. Is it possible to get NIC#2 to connect via NIC#1 and obtain another IP via DHCP? Any ideas? I'm running Vista x64.

Thanks in advance :)

Physically no but I think if you ran sort of a virtual adapter you can .Just how virtual machine software works.

Grand Master

+Gary7 Subscriber²

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You can have as many IP addresses as you want on virtual interfaces (supported by Linux natively, and through 3rd party stuff in Windows). It has nothing to do with the physical device, as it is a network stack/driver thing.

The ISP is only providing Service for ONE connection.

Apprentice

bestbuy

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Thanks for the reply guys.

You can have as many IP addresses as you want on virtual interfaces (supported by Linux natively, and through 3rd party stuff in Windows). It has nothing to do with the physical device, as it is a network stack/driver thing.

Yes, the only thing i can think of so far is to use VM, but the thing is I don't really want to run a full VM with an OS just to get an IP address.

Is there any 3rd party software that only install virtual interfaces?

VirtNet is the only one i found but it doesn't support vista x64 :|

Grand Master

+BudMan MVC

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  • MVC
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Are you just wanting multiple IPs? You do not need a virtual interface for that -- you can put many IPs on one interface.

post-14624-1227191548_thumb.jpg

Im not sure what your trying to accomplish exactly?? But you do not need any 3rd party software or running virtual machines to give your machine more than 1 IP.. You just can not be running dhcp and then add multiples.. Change to static - ie assign the IP on your machine, and then you can add lots more.

Apprentice

bestbuy

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All I'm trying to do is get 2 dynamic IP from DHCP on one computer, without additional hardware.

If you're feeling really adventurous, you could split the pairs to accomplish this.

Why not just get a small switch?

lol actually I did try that when running 10/100 LAN, but for something else. cut open my cat5 cable and use the 2 unused pairs. Now I'm running gigabit lan so all pairs are used.

I have a switch, but it's too much work to run another cable to that switch. I guess it'll work if i get another switch and let it sit beside my computer. I'm hoping to get this done by software though. :)

Apprentice

bestbuy

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And for what possible reason could you need 2 dhcp IPs from the same dhcp server for? Utterly pointless!!

This is just a possible workaround to a problem I have, so I just wanna see if anyone know a simple way to get 2 IP. I guess there isn't any, at least not on vista x64 :shifty:

Grand Master

+BudMan MVC

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  • MVC
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I already told you how to get 2 IPs, or 3 or 4 or 7, etc.. Just set your IP as static -- and then add more. But no you can not get multiple IPs from dhcp to the same interface.

And I am with Sawyer12 -- what is the problem your trying to workaround exactly??

Apprentice

bestbuy

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And I am with Sawyer12 -- what is the problem your trying to workaround exactly??

Well that's kinda off topic but anyway,

I have a second PC(winxp) which is used roughly once a week. My network setup is simple, both PC are connected to a swtich and the switch goes to a cable modem. My ISP provides 2 dynamic public IP. That's means the IP on my 2nd PC changes everytime I turn it on. I don't want that to happen since I have quite a few settings tied to that IP (firewall, routes, etc).

So possible solutions are:

1. leave 2nd PC on all the time

2. get addtional hardware

3. write some automation script to change all the settings tied to that IP, and run it on both computers whenever i turn 2nd PC on.

4. hold the IP (and of course i'll disable this virtual interface before i turn 2nd PC on)

I won't consider #1 and #2.

I'm not sure how to do #4 so I'm here to see if it's possible. I guess now i'm left with #3.

If you know any other possible solutions, please share ;)

btw thanks for all the input :)

Proficient

Bgnn32

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Would option 4 even work? Most ISP's will change the Dynamically assigned IP if the MAC Address of the hardware changes, I suppose you could spoof a MAC address if you really wanted to, but this seems way overly complicated for what you want to do. You really should just get static IP's.

Grand Master

+BudMan MVC

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  • MVC
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Bgnn32 exactly -- he would have to set the MACs of the different interfaces to be the same.

Even though he does not like the option -- I see little point to having machines directly connected to the net, I would get a router or run a linux distro as his router that allows for multiple IPs on the wan side interface. This should keep his public IPs pretty much the same since it would not go offline.

Apprentice

bestbuy

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I'd love to get static IP if I can... but no unless i upgrade to some high end business internet plan, with a static IP at an additional cost.

gigabit routers are kinda pricey. I sometimes do transfer large amount of data between computers and my apt doesn't have space for another computer to run linux...

I should start writing some automation script :rolleyes:

Grand Master

+BudMan MVC

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  • MVC
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Who said anything about a gig router?? Use a gig switch to connect your machines -- I also do large file transfers and backups, etc. and would never go back to 100mbit on the lan.

But we are not talking about the lan, we are talking about your public side -- I am quite sure you do not have anything close to a gig connection on the public side.. so your router does not need gig interfaces anywhere on it ;)

On the cheap its possible using dd-wrt or openwrt running on say a wrt54g to allow for multiple wan IPs - more often then not these are static IP.. But have a search and you will find some threads where they talk about using dhcp on the public side..

Here is a wiki page from openwrt showing using dhcp on the wan side.. This is more often then not used with multiple ISPs -- but should work just fine with same ISP, etc.

http://wiki.openwrt.org/OpenWrtDocs/Kamika...ion/MultipleWan

snippet;

--

This first is to create vlan (one per WAN connection)

in the /etc/config/network for two wan you'll have:

config switch eth0

option vlan0 "2 3 4 5*"

option vlan1 "0 5"

option vlan2 "1 5"

...

#### WAN configuration

config interface wan

option ifname "eth0.1"

option proto dhcp

config interface wan2

option ifname "eth0.2"

option proto dhcp

During this tutorial I'lL consider both your ISPs use DHCP, but you can easily change it to static IP.

--

So looks like to me for the cost a wrt54GL router your problem would be solved ;)

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