Iptables, multiple IPs and routing

mbgd · 09-07-2012, 07:21 AM

Hello,

I need help setting up routing using iptables :

I have a set of 5 external IP addresses, eg. 99.99.99.1 - 99.99.99.5
I have set up eth0 :

eth0 -> 99.99.99.1
eth0:1 -> 99.99.99.2
eth0:2 -> 99.99.99.3
eth0:3 -> 99.99.99.4
eth0:4 -> 99.99.99.5

I wish to set up routing so if someone connects to 99.99.99.2, all the packets are routed through this IP instead of the main one 99.99.99.1.

Is this possible ?

wildwizard · 09-08-2012, 01:36 AM

All the IP's are on the same physical interface therefore what your asking is not possible.

The IP's are not so much routed through the first IP as much as they all share the same physical device thus there is no distinction between them.

Now the question you didn't ask but you probably want answered is this :-
How do I see how much traffic each IP gets?

This can be done with iptables simply create a new chain that does nothing and then on the INPUT chain you can create a rule that matches any packet for IP(1) and jump it to that new chain, do this for each IP(x) address and you now have a crude counter.

The effect of the empty chain is nothing as it will default to ACCEPT but it does allow you to add further rules later if you need to protect things, while maintaining the same basic packet counts.

mbgd · 09-15-2012, 05:52 AM

Quote:

Originally Posted by wildwizard

All the IP's are on the same physical interface therefore what your asking is not possible.

The IP's are not so much routed through the first IP as much as they all share the same physical device thus there is no distinction between them.

Now the question you didn't ask but you probably want answered is this :-
How do I see how much traffic each IP gets?

This can be done with iptables simply create a new chain that does nothing and then on the INPUT chain you can create a rule that matches any packet for IP(1) and jump it to that new chain, do this for each IP(x) address and you now have a crude counter.

The effect of the empty chain is nothing as it will default to ACCEPT but it does allow you to add further rules later if you need to protect things, while maintaining the same basic packet counts.

What would be the easiest way to create virtual physical interfaces ? VMWare Workstation for linux ?