Post by Chris G
I have just installed ubuntu onto a machine and have connected it to
my LAN. The router provides DHCP and the new machine is up and
running on the network.
How do I connect *to* the machine? I need to know its IP address and,
as there are a few devices which get their address by DHCP it's not at
all obvious what the machine's address is.
Eventually I will probably give it a fixed address (for this reason
sudo apt-get install nmap
and scan for machines on your network. Example:
$ sudo nmap -sP 192.168.2.0/24 |grep up
Host 192.168.2.1 appears to be up.
Host 192.168.2.100 appears to be up.
Host main (192.168.2.101) appears to be up.
Host main3 (192.168.2.104) appears to be up.
Host 192.168.2.108 appears to be up.
Nmap done: 256 IP addresses (5 hosts up) scanned in 2.488 seconds
In the above example:
192.168.2.1 is a router
192.168.2.108 is a router 
192.168.2.101 is a WinXP machine
192.168.2.100 is this machine
 machines on the other side of 108 aren't shown as they are on a
different subnet & I only scan the 192.168.2.0/24 in this example. You
can google for nmap to find out how to scan outside of your subnet. Just
be careful that you don't go scanning too far as some/many/all networks
find scans to be intrusive.
If you want details (MAC address etc), then use the '-vv' mode:
$ sudo nmap -vv -sP 192.168.2.0/24
and you'll get the MAC addresses for the hosts that are up.
If you prefer a GUI frontend to nmap, you can try zenmap:
sudo apt-get install zenmap
Disclaimer: I've not used zenmap (yet), but added info is here: