Setting multiple IPs on a single NIC

[carlito]

Can multiple IPs be set on a single NIC?
Are there any risks? Because I don't have enough PCI slots left but I want to use all my 4 assigned IP addresses on my server.

Thanks.

[ultan]

of course they can But then it may be unstable and crash your whole card...
I would not suggest it.
But why don't you have any PCI slots left? There should be 5 and you used all of them?? :S

[cristobal]

I second the adding of another PCI, because of the stability issues.
What are you using for all your PCI slots anyway??

[jmack]

Umm - whoever said something about stability doesn't know what they are talking about. You can add (alias) many IPs to a single card - one of the great features of unix/linux systems.

I have aliased as many as 20 ips to a single PCI card before. This is usually done on firewalls that have a number of servers on a private lan. The public IP's are NAT'd to the private ones using something like natd or ipnat, working in conjunction with a firewall package.

I add aliases to interfaces in freebsd like this:

# ifconfig interface alias ip_address subnet_mask

'man ifconfig' will give you more detail.