How can I detect if a host changes its IP address in the network? IP addresses are statically assigned.?

Question

Is there a free tool for such kind of detection in real time.

I have two ideas at the moment.

1.)Fetch mac and ip address table using snmp and compare them somehow in an automated way.
2.)Use nmap script. Have no idea about this at the moment.

Note: Please stick to the question and dont give ideas of implementing DHCP etc..

Thankyou :)

Answer 1

If you allow ping response and you are on the same network, you can write a script that simply:

ping the host (short 2 packet)

if response, inspect arp table for entry.



You can prebuild the arp table with ip address and Macs.



If you want a monitor AND do this, you can run nagios. It has a contributed script that checks the hosts mac address, you would need to encode the result, the mac for each host. It does what you think, an arp table lookup.



Nagios runs on Linux and Windows (although I've never run it on Windows).



Method 1 would work fine. Perl has both the Net::SNMP, but I believe there is not standard for where that info is located. You probably want (in Cisco) the mac-address table and not the arp table. You can also just use snmpwalk to get the info and write your own script around it.

Answer 2

Spiceworks

Answer 3

id just dig through the dhcp logs and see what requests what based on mac address,

Answer 4

Dynamic DNS is the topic to look up.

Answer 5

I searched for spiceworks but there is no such feature in it.