topic Re: DHCP available /used addresses in Operating System - Linux

DHCP available /used addresses

Alexander Chuzhoy — Tue, 28 Feb 2006 11:31:53 GMT

Is there a command to see how many free/used addresses are in dhcpd pool(s).
Parsing dhcpd.leases isn't satisfying cause I also have static addresses that don't appear there.
I'm using RedHat (any version).
Thanks in advance.

Re: DHCP available /used addresses

Ivan Ferreira — Tue, 28 Feb 2006 14:31:13 GMT

If dhcp.leases does not contains all information you need, you could combine it with nmap to check what ip addresses are used (nmap -sP static-address-range).

Re: DHCP available /used addresses

Stuart Browne — Tue, 28 Feb 2006 15:00:18 GMT

Why do you have static IP addresses within a DHCP pool ?

If you're going to make addresses static, then they should either be assigned by DHCP (using hwaddress), or be outside of the DHCP pool.

Why do I say this? DHCP thinks it's in control of the entire pool. It thinks it can assign *any* address from this pool to any requesting machine. This means that some of your static's might get assigned to another machine on the network, causing nastyness and IP conflicts.

Re: DHCP available /used addresses

Alexander Chuzhoy — Tue, 28 Feb 2006 15:27:57 GMT

Thanks for your replies.
1. I can come up with some workaround myself, but the question is whether there's a command to do this.

2. What I mean by static addresses is that the addresses are binded to mac in dhcpd.conf file.

What I need is a tool/command to see available/occupied IP addresses on dhcp server.

Re: DHCP available /used addresses

Arno Kuyper_1 — Tue, 28 Feb 2006 16:27:15 GMT

Alexander,

Take a look at this tool -> Sauron.
http://sauron.jyu.fi/.
It's a web based DNS & DHCP configuration tool based on a SQL-database.

Hope it helps,

Arno

Re: DHCP available /used addresses

Sergejs Svitnevs — Wed, 01 Mar 2006 02:14:56 GMT

reportdhcp.pl CGI script can tell at a glance how many leases are available in each network, and how many of these are currently â activeâ .

http://www.omar.org/opensource/reportdhcp/index.html

Regards,
Sergejs