Jump to content
xisto Community
miCRoSCoPiC^eaRthLinG

Question: Multiple NICs Multiple IPs - Possible ?

Recommended Posts

Question for the networking gurus here...

 

Supposing I want to stack in a bunch of ethernet cards into the same server / workstation:

Can I assign a different IP address to each card - so that it's possible to make the same machine a part of different subnets ? That's my main objective, i.e. make the machine be hooked simultaneously to different subnets.

What is the maximum number of Ethernet cards I can stack in (apart from physical system limitations - read FREE SLOTs)

Can anyone point me to some good resources on this?

Thanks a tonne as always :unsure:

 

Regards,

m^e

Share this post


Link to post
Share on other sites

Can I assign a different IP address to each card - so that it's possible to make the same machine a part of different subnets ? That's my main objective, i.e. make the machine be hooked simultaneously to different subnets.

Yes, no problem. I do that every day. Simply be careful, each NIC must have 255.255.255.0 as netmask, this is mandatory if you want to work with subnets. If you work with nets, you can have 255.255.0.0 as netmask.

What is the maximum number of Ethernet cards I can stack in (apart from physical system limitations - read FREE SLOTs)

I heard that some Unix systems are limited to 7 NIC's, do you have more than 7 ones ?

Can anyone point me to some good resources on this?

Sorry, this is my own experience, no resources other than myself.

Share this post


Link to post
Share on other sites

1. Yes, that is absolutely possible.2. Aside from hardware/physical restrictions, there is no maximum amount AFAIK.3. I don't really know, but I'm sure I can come up with an answer to any problem.@Yordan: your answer to point 1 isn't correct; they do not require any particular mask. In reply to point one, all you have to do is physically attach the NIC to the relevant network, assign it an IP address from the relevant network's scope (and of course whatever subnet mask the network is using), and you're good to go.

Share this post


Link to post
Share on other sites

Cool. Thanks guys. So in effect, this machine can act as a connecting bridge between the different subnets, right ?If so, here's another question. Can I configure this system in such a way that it allows a few specified IPs from one subnet to gain access to systems on the other subnet ?? Some sorta chain-rules that'll allow very limited number of systems to interact with a similarly limited number of systems on another subnet... ? So far I've worked with single subnets only - haven't really experimented around with running more than one of them parallely and trying to make systems interact over the disjoint rings. Any clue on this ?

Share this post


Link to post
Share on other sites

Yes, but I believe you need RRAS (Routing and Remote Access) for that (assuming you're using Windows), as you're essentially turning the computer into a router.For the second question, you can configure IP address filtering on the relevant network adapters (i.e. "allow all except *IPs*" or "block all except *IPs*"), and you can do it all from the RRAS console.To get more "Big Brother" on everyone's asses, you'll need ISA server. :unsure:

Edited by eurotrash (see edit history)

Share this post


Link to post
Share on other sites

Oh great - thanks man. Now I'll probably be using Linux on this box.. So any idea how to do the same as the RRAS console you mentioned? Should setting up some IPTables chain-rules suffice ? Or do I have to use any other kind of routing sw ?

Share this post


Link to post
Share on other sites

Oh great - thanks man. Now I'll probably be using Linux on this box.. So any idea how to do the same as the RRAS console you mentioned? Should setting up some IPTables chain-rules suffice ? Or do I have to use any other kind of routing sw ?


i dont know if this will work..
there is an IPtables configuration in your linux box

from there you can create rules on what will you do for each connection that is being requested into your computer.

--

i use quad slot NIC
each slot is a new IP and new Mach address

i identify the connections via the source and destination mach address..
judge what to do to the connection all via the IP tables rules..

well LINUX rocks...
---

cant explain fully here..
Edited by vhortex (see edit history)

Share this post


Link to post
Share on other sites

Hey m^e,

1. Multiple NICs can be connected to your PC, each will be assigned an IP and can be made to be on different subnets, however some form of routing software would need to be installed, although I believe Linux has this capabilities already, if not, you'd find a lot about it, keyword: linux router.

2. No known limitations apart from physical (I've heard 10 though), though depending on the type of computer, it can some what affect the networks performance slightly, especially if trying to handle multiple requests at once. Hopefully you're got quite a lot of RAM and a powerful processor, for my router firewall pc I use a dual processor computer, which might be overkill for my small network but better being over than under.

3. I guess this link could help you though I have not read all of it:

http://www.linuxjournal.com/article/5826


Cheers,

MC

Share this post


Link to post
Share on other sites

As far as I know, only problems you can face are performance related. And that of course depends on the nature and volume of the traffic. The actual router boxes of today aren't really that much different from your home PC. Just stick with Linux... I can't imagine to horror of trying to do this with Mr. Gates' OS...

Share this post


Link to post
Share on other sites

Okay, there are hardware limitations other than the lack of available slots. For example, every NIC needs and IRQ, and a computer can have at most 256 IRQs, so at most 256 NICs. Except some IRQs are predefined, like timer, etc., so even fewer. Further, every NIC probably needs to be associated with a hardware port on the computer, which there are 65356 of, but many devices get more than one port, so another possible limitation. But when you think of the fact that 386 and 486 chips can be used to make 24 port switches, 24 NIC cards doesn't seem too impossible.~Viz

Share this post


Link to post
Share on other sites

After reading most of these post, is it possible to have to pc's that are networked, in the same house. The problem that im having is that i cant be one the same wbsites my brother gets on. If he logges on and is on the site, hes fine, but when I logg on to the sam esite it shows me logged in as him, and on his screen it logges him, off. and im sure its because of the same ip.So what could I do to eliminate this small problem

Share this post


Link to post
Share on other sites

and im sure its because of the same ip.So what could I do to eliminate this small problem

you should open another topic, because your question does not concern the current topic.
It seems that your site has a duplicate-user protection, based on IP address.
Does your question mean that you ask for a way of cheating, asking how to provide a false IP address ?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...

Important Information

Terms of Use | Privacy Policy | Guidelines | We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.