dhcpd.leases(5)

NAME
       dhcpd.leases - DHCP client lease database

DESCRIPTION
       The  Internet Software Consortium DHCP Server keeps a per
       sistent database of leases that  it  has  assigned.   This
       database  is  a  free-form ASCII file containing one valid
       declaration per  lease.   If  more  than  one  declaration
       appears  for  a  given  lease, the last one in the file is
       used.  The file is written as a log, so  this  is  not  an
       unusual occurrance.

       When dhcpd is first installed, there is no lease database.
       However, dhcpd requires that a lease database  be  present
       before it will start.  To make the initial lease database,
       just create an empty file called /var/db/dhcpd.leases.

       In order to prevent the lease database from growing  with
       out  bound,  the  file  is  rewritten  from  time to time.
       First, a temporary lease database is created and all known
       leases are dumped to it.   Then, the old lease database is
       renamed /var/db/dhcpd.leases~.   Finally, the newly  writ
       ten lease database is moved into place.

       There is a window of vulnerability where if the dhcpd pro
       cess is killed or the system crashes after the  old  lease
       database  has been renamed but before the new one has been
       moved into place, there will be  no  /var/db/dhcpd.leases.
       In this case, dhcpd will refuse to start, and will require
       manual intervention.   DO NOT simply create  a  new  lease
       file when this happens - if you do, you will lose all your
       old bindings, and  chaos  will  ensue.    Instead,  rename
       /var/db/dhcpd.leases~  to  /var/db/dhcpd.leases, restoring
       the old, valid lease file, and then  start  dhcpd.    This
       guarantees that a valid lease file will be restored.

FORMAT
       The format of the lease declarations is not currently doc
       umented.

FILES
       /var/db/dhcpd.leases

SEE ALSO
       dhcpd(8) dhcp-options(5) dhcpd.conf(5) RFC2132, 
       RFC2131.

AUTHOR
       dhcpd(8) was written by Ted Lemon lt;mellon@vix.com under a
       contract with Vixie Labs.   Funding for this  project  was
       provided  by  the Internet Software Corporation.  Informa
       tion about the Internet Software Consortium can  be  found
       at http://www.isc.org/isc.