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So I would like to find out what computers in a particular subnet are up. Usually I would just use arp -a for that, except for the fact that sometimes, I have to ping an IP before its MAC address gets added to the list. And take a look at this:

What's with all those invalids?

I've heard of broadcast pings, but it seems that every OS nowadays doesn't respond to broadcast pings because of some old attack called the Smurf attack. Bottom line, ping -b 192.168.1.255 or on Windows, ping 192.168.1.255 doesn't work. Oh, I think I got OS X to respond to a broadcast ping. But it wasn't the only computer on the subnet.

Then there's this utility called Net World Scanner for Windows. Turns out it only works with Windows computers with a NetBIOS name - my Linux virtual machine that's not running Samba never showed up.

Any ideas?

Crayon Shin Chan wrote:

Then there's this utility called Net World Scanner for Windows. Turns out it only works with Windows computers with a NetBIOS name - my Linux virtual machine that's not running Samba never showed up.

Any ideas?

Sounds to me like your LinuxVM doesn't have a IP addr. Can you check and see what IP address it's using?

192.168.1.4 via DHCP.

What's the IP address of the windows box it's running on?

Edit: added clarification on the question.

192.168.1.2 windows desktop
192.168.1.3 windows laptop
all assigned by DHCP

EDIT: no computer is missing in the above arp -a output. My point is there are entries with invalid MAC addresses... and it's not guaranteed that the computers on the arp -a output are the only ones on the subnet.

I'm more interested in the Net World Scanner output. Arp -a only lists the mac addresses that machine knows and they time out after not hearing for them from a time. A broadcast ping used to be able to take care of this problem as everything would generally respond, but now many devices do not reply to a broadcast ping. I just tried the Net World Scanner and it definitely sucks. Try netping, that was able to find everything on my network.

http://www.mikrotik.com/thedude.php

There's a neat Windows thing that lets you scan entire subnets. And it's free!

Get a managed switch and dump the MAC-to-port mapping table.

Net World Scanner only detects the two Windows computers.

I've downloaded the Dude, haven't installed it yet. It looks way too complex for what I want. Mapping functions? Also, managed switches could buy me a whole new computer.

I use Netscan (http://www.softperfect.com/products/networkscanner/). It's free, simple and lists every machine (real & virtual) on my network in a minute or so.

Try fast resolver.

http://www.nirsoft.net/utils/fastresolver.html

nmap in linux

flip-mode wrote:

nmap in linux

nmap works fine on Windows as well...