Having issues with old data, DNS/DHCP

I'm having a few issues with DNS/DHCP, I'll ask about these one at a time.

bind 9.9.7-P1, dhcpd 4.2.5-P1, Slackware 64, 14.1

First, old leases seem to hang around forever in /var/state/dhcp/dhcpd.leases, example below. Those listed are from back in March. None of the computers in the lease file are currently connected. Why are they hanging around?

Should static IPs be in there? If so, something is not working.

# The format of this file is documented in the dhcpd.leases(5) manual page.
# This lease file was written by isc-dhcp-4.2.5-P1

lease {
  starts 6 2015/03/07 11:46:52;
  ends 0 2015/03/08 11:46:52;
  tstp 0 2015/03/08 11:46:52;
  cltt 6 2015/03/07 11:46:52;
  binding state free;
  hardware ethernet 00:16:17:46:70:69;
  uid "\001\000\026\027Fpi";
lease {
  starts 2 2015/03/17 17:01:10;
  ends 3 2015/03/18 17:01:10;
  tstp 3 2015/03/18 17:01:10;
  cltt 2 2015/03/17 17:01:10;
  binding state free;
  hardware ethernet c8:9c:dc:6e:24:e8;
  uid "\001\310\234\334n$\350";

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My dhcpd.conf file:


ddns-updates on;
update-static-leases on;
allow unknown-clients;  # default, deprecated (man dhcpd.conf)
ignore client-updates;  # see https://www.centos.org/forums/viewtopic.php?t=29256, man dhcpd.conf: ignore client-updates
ddns-update-style interim;
default-lease-time 86400;

log-facility local7;

zone hprs.local. { primary; }
zone 0.168.192.in-addr.arpa. { primary; }

subnet netmask {
    option routers;
    option domain-name-servers;
    option domain-name "hprs.local";
    ddns-domainname = "hprs.local.";
    ddns-rev-domainname = "in-addr.arpa.";

# Web Server (Linux)
host webserver {
    hardware ethernet 60:A4:4C:61:9C:FE;

# SQL Server Database Server (Server 2008)
host server {
#    hardware ethernet 40:E0:4C:39:7F:61;
    hardware ethernet 3C:1E:04:47:16:B0;

# Network Attached Storage (Linux)
host ohprsstorage {
    hardware ethernet F4:6D:04:60:04:38;

# COMMON workstation (WIN7)
host COMMON {
    hardware ethernet 2C:27:D7:2F:CF:7A;

host ricoh {
    hardware ethernet 00:26:73:55:63:AB;

# Postage meter
host postage {
    hardware ethernet 00:10:60:B6:72:D4;

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Daniel McAllisterPresident, IT4SOHO, LLCCommented:
The file is essentially a LOG file, the "old" leases stick around because the DHCP server likes to be kind and serve the same address to the same host when possible.

The entries have "ends" values, so there is nothing wrong.... when an address lease expires, the DHCP server is free to reassign it (but there is no requirement for it to do so).

There is a decent description of what I'm talking about, as well as a script to display only active leases, located at http://askubuntu.com/questions/219609/how-do-i-show-active-dhcp-leases

I hope this helps


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MarkAuthor Commented:
So ... "old" leases never get purged from that file? It just grows forever?

Dan: that script worked well.

IPs statically assigned are not in the lease file, eh? Is that correct? None of my dozen-ish static assignments show as active leases.
Daniel McAllisterPresident, IT4SOHO, LLCCommented:
Yes, again it is as much a LOG file as anything.

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