Problems with dhclient-eth0.leases file

Ok I have a perl program that reads this file and tries to determine when the lease was set. However when I look at this file I get some messed up times. Here is essentially how the last part of my file looks :


dhcp-lease-time 21600;
dhcp-renewal-time 10800;
dhcp-rebinding-time 18900;
renew 4 2003/9/26 23:27:36
rebind 6 2003/9/27 02:03:33
expire 6 2003/9/27 02:48:33


My question here is how does the file dhclient-eth0.leases get written. Where is the data in the file generated from? What do the values in this file mean. what are the numbers after renew, rebind, expire mean ie ... 4, 6, 6. Any help on this would be great. If this post is in the wrong place I apologize.
Thanks.