You can either find out your IP address through the command line interface or through a Web-based interface that can determine your address for you.
Through command line interface:
Note: Root access may be required to run these commands. These commands will all be launched from the command line.
1. Launch a command line interface. (This will vary depending on operating system distribution.)
2. In the resulting command line window or screen, type ifconfig.
3. Press Enter. For example, typing ifconfig at the command line:
[sygny@linuxbox /home]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:10:5A:1A:DC:65
inet addr:126.96.36.199 Bcast:188.8.131.52 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:18940 errors:1 dropped:0 overruns:0 frame:2
TX packets:11554 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:4087250 (3.8 Mb) TX bytes:2499423 (2.3 Mb)
Interrupt:11 Base address:0xd000
In the example above, the IP address is labeled inet addr:184.108.40.206.
The subnet mask is listed as Mask:255.255.255.0.