Statistics on number of users in 24h period

Brett Charbeneau brett at
Thu Sep 12 15:29:54 UTC 2013

	I'm grateful for your response, Keith!
	And the neat perl script is useful too.
	This is the exact tree I was trying to bark up, but I can't seem to get 
DD-WRT's implementation of DHCP (purported to be 4.1-ESV-R2-1) to log at that 
	This may be a limitation/feature of DD-WRT. They offer "mini" and "mega" 
firmware versions, I've yet to try the latter which may offer this flexibility.
	Thanks again for the tip!

Brett Charbeneau, GSEC Gold, GCIH Gold
Network Administrator
Williamsburg Regional Library
7770 Croaker Road
Williamsburg, VA 23188-7064
(757)259-4079 (fax)    brett at

On Thu, 12 Sep 2013, Neufeld, Keith wrote:

NK> > As a public library, we are really interested in determining the number of unique devices that connect to our wireless network daily.
NK> If you configure the DHCP software to log to a syslog server, the log file will have entries somewhat like this:
NK> Sep 12 09:56:26 netsvc-507 dhcpd: DHCPACK on to 00:1a:a0:4b:6b:67 (GW-223-KIOSK3) via
NK> which will allow you to determine the number of unique clients; whereas analyzing the current lease file will only show you the last client that used each particular IP, so reuse of IPs will not get counted.
NK> Running
NK> perl -ne 'print "$1\n" if /DHCPACK on \S+ to (\S+) /' dhcp.log | sort -u | wc -l
NK> on today's DHCP syslog file gives me 11236 unique clients granted IPs on our network so far today.  It could be more sophisticated, but it's quick and easy -- if you're able to syslog.

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