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  man pages->Tru64 Unix man pages -> server.pcy (4)              



NAME    [Toc]    [Back]

       server.pcy - BOOTP and DHCP server policy

DESCRIPTION    [Toc]    [Back]

       The  server.pcy  file  is a text database that governs the
       behavior of BOOTP and DHCP servers.  If the  joind  daemon
       is  invoked to use text databases, it reads the server.pcy
       file on startup.  If the JOINCONFIG variable is present in
       the  joind environment, it specifies the directory for the
       server.pcy file; otherwise, joind searches  the  /etc/join
       directory.    Defaults   exist   for  all  parameters  and
       switches, so it is not an  error  if  the  file  does  not

   Format    [Toc]    [Back]
       Blank  lines  are  ignored.  The number sign character (#)
       introduces a comment, which continues to the next newline.
       Each  new  policy  option must begin and end on a separate
       line.  Policy options are introduced by a keyword, and may
       be Boolean, or may take a value separated from the keyword
       by whitespace (but not a newline).  If an option  is  present
  more  than once, only the value attached to the last
       occurrence is used; earlier value(s) are ignored.

   Keywords and Values    [Toc]    [Back]
       This Boolean tells the server that if a DHCP client  needs
       a  boot file, send the name of that file in the BOOTP file
       field and not as a DHCP option (option 67).  BOOTP clients
       always  receive  a boot file name in the file field.  This
       is disabled by default.  This Boolean tells the server  to
       ignore the value of the broadcast bit and always broadcast
       a reply, even when the client can receive a pseudo unicast
       reply.   This  was needed by some Cabletron smart bridges.
       This is disabled by default.  This Boolean is for  clients
       that  do  not  use DHCP client identifiers.  The parameter
       tells the server to use the client's hardware  address  as
       its  identifier,  but to ignore the hadware type field. In
       the JOIN database, the identifier is stored  with  a  type
       field  of  zero  (which is also the type for those clients
       that are using client idetfifiers).  This is  disabled  by
       default.   For  each subnet that the BOOTP and DHCP server
       administers, two lists are maintained in memory: a  "free"
       list  containing IP addresses available for allocation and
       a "provisional" list containing addresses that  have  been
       tentatively  assigned,  which are awaiting client approval
       in the form of a DHCPREQUEST packet.

              The value of seconds determines how long an address
              will  remain  on  the  free  list before the server
              determines  that  the  client  does  not  want  the
              offered  address.   The  free list does not contain
              every address available to the server;  instead  it
              acts  as  a cache of addresses which the server can
              offer without reading the disk.

              If a new client makes a  DHCPDISCOVER,  and  no  IP
              address  exists  for the client in permanent store,
              the server first goes  to  the  free  list  for  an
              unused address.  If the free list is exhausted, the
              server first reclaims any addresses on  the  provisional
  list  which  have expired.  It then extends
              this list to be free_list_size in length by reading
              from   the  disk.   This  has  a  benefit  in  that
              addresses  are  usually  offered   in   numerically
              increasing order. Making the ttl too short will not
              give clients  an  opportunity  to  confirm  offered
              addresses; making it too long will waste memory.

              Default:   60  See  the  explanation  under  provisional_ttl.
  If this  number  is  too  low,  server
              response  time  will  suffer. If it is too large it
              has the undesirable effect of requiring the  server
              to  reclaim expired leases before they are actually
              needed for reallocation to new  clients.   Although
              this is not an error, a desirable feature of server
              operation is  that,  whenever  possible,  a  client
              requesting a new IP address should get back its old
              address, unless that address has been leased  to  a
              new client.

              Default:      8     This     option     and     the
              "assign_name_by_ipaddr" option are mutually  exclusive.
   They govern how the server assigns names to
              hosts.  This option tells the server to bind a name
              to  the  MAC address. That way, if the client moves
              to a new address, it keeps  the  same  name.   This
              tells  the server that if a lookup to the name service
 (gethostbyaddr(3)) succeeds, the client should
              receive  the name that was found at the IP address.
              This Boolean option  is  compatible  with  previous
              options.  It instructs the server that if it is not
              able to find a name for the client  by  application
              of  the  two  previous  policies, it can accept the
              name the client suggests for itself providing  that
              this  is not in contradiction with values currently
              in the name service.  If a contradiction exists, or
              this  policy  is  not  enabled,  joind consults its
              namepool  or  prefix.   (See  namepool(4)).    This
              Boolean tells joind to support BOOTP clients.  When
              replying to BOOTP clients, the server does not  use
              the DHCP extensions to the BOOTP protocol.  This is
              enabled by default.  This Boolean is only valid  if
              the  support_bootp option is enabled.  When on support_bootp
 permits the server to permanently assign
              an  IP address from its free pool to a BOOTP client
              in the event that no permanent  binding  exists  in
              bootptab.   Normally  the BOOTP and DHCP server can
              only service BOOTP clients for which such a binding
              pre-exists.  Before the server offers an IP address
              to a client it may first check that the address  is
              not  in  use by sending an ICMP echo request. If an
              echo is received, it means that the address  is  in
              use,  and the server selects another.  This parameter
 specifies the time (in milliseconds)  that  the
              server  waits  for the echo.  If this value is zero
              or negative,  the  server  does  not  perform  this
              check.   Disabling  this  check may be necessary in
              certain environments to  decrease  server  response
              time  to an acceptable level; this release of joind
              is not multithreaded, so  the  server  idles  while
              awaiting the response.


       Files: namepool(4)

       Specifications: RFC 1541, RFC 1542 delim off

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