List the IP Address of all computers connected to a single LAN

Bloodyaugust picture Bloodyaugust · Jan 3, 2010 · Viewed 13.1k times · Source

I am writing a program where you connect, for various reasons, to other computers in a LAN. However, rather than having to input the IP address for multiple computers (a pain in the butt), I was wondering if there is a way to list the IP addresses of all the computers in a LAN. I have researched all day, and as of yet have found nothing suitable. Is this because nothing of this sort exists? Thank you in advance.

EDIT: It would seem that with the many views this post is getting, I should post my actual solution. In general, the naming conventions for computers IP addresses on a LAN are the same. example being 192.168.2.*, * being replaced with any valid number. My program detects the IP address, displays it to the user, then asks for the first 3 blocks of IP. It then sequentially scans up to 200 in the given IP naming convention by pinging and waiting for a response. No response, no computer. It can do everything you can do with an IP once it knows it has a computer behind it.

Answer

Chandra Patni picture Chandra Patni · Jan 3, 2010

1) Read the subnet mask and calculate all the IP addresses in the subnet mask you are in. Then you can either user ICMP ping (standard ping) or ARP ping to list all the valid IP addresses. ARP Ping is much reliable in a subnet setting.

2) You can nmap to list all the hosts

nmap -nsP 192.168.10.1/254 | grep ^Host