Static IP help

[hdbbj]

I have a static IP and I believe I assigned it properly to the server. I'm using ubuntu 9.10 server edition.

auto eth0
iface eth0 inet static
address xxx.xx.xxx.x - my static IP
netmask xxx.xxx.xxx.xxx - subnetmask
network xx.x.xx.xx - currently I have this set to what my routers dhcp starting range is
broadcast xx.x.xx.xxx - currently I have this set to what my routers dhcp ending range is
gateway xxx.xx.xxx.xx - I have this set to the gateway the tech wrote down for me

The issue I'm having is that postfix isn't seeing internet e-mail and I think the issue is because it's listening on the router IP and not my static IP. I just want to make sure my settings are correct before moving on with troubleshooting further.

So if someone could explain what network, and broadcast values should be I'd appreciate it.

Edit: with the information above my website is fine when my static IP is called in the browser or via domain name. Internet connectivity works great so I'm guessing the values are correct, I just need clarification.

Thanks for any input!

[topdog]

You can check what address postfix is listening to using this command

netstat ntlp|grep :25

Here is a primer on networking http://www.linuxhomenetworking.com/w..._to_Networking

[hdbbj]

Thank you Topdog.. that was a very long but notable read. Now time to setup my values based on those calculations.

Everything seems to be working and I still have internet connectivity so I'm guessing it works!