network, gateway, subnet mask, and IP.... What is 'network' for?

[dmantic]

I am trying to set up my first colocated server. It is running linux - CentOS 4.1.

My colocation facility sent me the following 4 pieces of information:

network (single IP address)
gateway (single IP address)
subnet mask
IP range (5 consecutive IP addresses)

My problem is that I don't know what the network IP address is for. When I configure CentOS to use a static IP I just choose the first of the 5 IP addresses they sent me to use as the IP of the server, and then I supplied the gateway and subnet mask when prompted. But there was never any place for the 'network' address.

So what is this address for? I can't get networking to work so I am thinking that this is somehow related.

When I do ifconfig it sees eth0 and it has the right IP and gateway and subnet mask, but I can't see the machine on the network and I can't get to anyplace out on the network from my machine.

[Samoth]

It could be your server's IP. Try entering that. This is different from the Gateway in that the Gateway is the router that directs your packets to your desired location

BTW Slackware Rox

[Roxoff]

IIRC, the network address is the base address for your block of IP's. You should find that, of the 5 static IP's you have been given, the 1st is the network address, the last is the broadcast address; dont use either of those - use the middle ones for your equipment.

My suggestion is that one should be your mail gateway address, one your internet access address, and maybe use the 3rd for plugging into a DMZ for a seperate web/services server.

[sarumont]

The 'network address' is actually the network number. It's the IP at the beginning of a subnet that is used to denote that subnet (with a subnet mask or in CIDR notation). It's not a useable IP and depends on the size of the subnet that you have. It could be calculated using the subnet mask and IP list if you haven't found it already.