Question : How to find all ip addresses in use and manage them...

Hello

I work at a non profit.  We use statically configured IP addresses.  Unfortunately, our lists are no longer up to date and we are constantly running into problems with multiple people configured to a single ip address.

My question is 2 fold.  What tool can I use to find all ip addresses in use.  Ping will not work as alot of the boxes are windows xp with their firewalls turned on.  They do not respond to ping, but the address is in use.  I need a mechanism for detecting ip addresses in use that will work even if the default windows xp firewall is turned on with no exceptions checked.  I figure there must be some type of way of doing it, b/c if I use an ip address that is in use Windows will tell me.  What are some different methods for discovering ip address use.  We are using a windows 2k active directory.  Assume the network has win 98, 2k, and xp boxes.  Assume at a given time a machine may be turned off.  I am looking for a tool that can discover ip address use that is not based solely on ping.

2 Once I have discovered all the ip addresses in use, what is a good tool for managing them (free).

Thoughts ?  

Answer : How to find all ip addresses in use and manage them...

Check out solarwinds network discovery tools
http://www.solarwinds.net/products/toolsets/engineer.aspx#NDT
You can download a functional 30 day eval of the whole set
Using all the tools available, you can get the IP's of systems even if their firewall won't let you ping them.
There is always an arp cache of mac-address to IP mapping somewhere on the network. The mac-address scanning tool and switchport mapper tools help complete the picture beyond the ping sweep scanners
There's also a DNS audit tool there that helps you see dns errors and ip mismatches