Multiple IPs
 

I am running a Red Hat box as a router using iptables and we recently added 2 IP address for a total of 3. Is there anything I need to do for Linux to recognize these IPs other than porting them through iptables? Is there a way to assign more than a single IP to a network adapter. I assume you must.

-pat

Re: Multiple IPs
 

you can do this using inetd

http://www.google.com/linux?hl=en&lr...=Google+Search


[EDIT]

this post is bogus, MY BAD...

Are you sure?
Inetd is for running services like ftp servers that listen on a port. Instead of having the server software loaded all the time using up memeory inetd starts it up only when it is needed.

I think you have to set up mulitiple ip in the lower level network stuff before messing with inetd.

example
ifconfig eth0:0 192.168.100.1

The last post is absolutely correct.

ifconfig eth0:0 xxx.xxx.xxx.xxx is the format for a second IP which will resolve to the same NIC.

ifconfig eth0:1 etc etc

These are not retained through a boot up though. To make them persistant, you need to create a file with the setup.

On Red Hat, cd to /etc/sysconfig/network-scripts. There you will see the configuration file for your network card. It is named ifcfg-eth0 You will need to make a new file named ifcfg-eth0:0 for the second "Virtual IP" address.

Once you have a ifcfg-eth0:x file for any extra IP Addresses that will be bound to that card, you simply restart the network. This will be good thru boots.

my bad... sorry guys... i must have been trippin'... please ignore my first post, patpawlowski...

http://www.troubleshooters.com/linux/ipalias.htm


i'd like to add that iptables doesn't work with virtual interfaces, so instead of using (for example) "eth0:2", in your iptables script, use the ip you assigned to the virtual interface...

I have an iptables script that runs at startup. I was considering adding the appropriate commands there. The reason being that I frequently make changes to the script and this would allow me easy access to the IP configuration also. Does anyone see any problem with that?

Sounds good to me, I'd consider having your script called from the /etc/rc.d/rc.local file.