dhcpcd(8)	  Linux System Manager's Manual		dhcpcd(8)

NAME
       dhcpcd - DHCP client daemon

SYNOPSIS
       dhcpcd  [-dknrBCDHRT] [-t timeout] [-c filename] [-h host-
	    name] [-i vendorClassID] [-I clientID] [-l leasetime]
	    [-s [ipaddr]] [-w windowsize] [interface]

DESCRIPTION
       dhcpcd  is  an implementation of the DHCP client specified
       in RFC2131 (when -r option is not specified)  and  RFC1541
       (when -r option is specified).

       It  gets the host information (IP address, netmask, broad-
       cast address, etc.) from a DHCP server and configures  the
       network	interface  of the machine on which it is running.
       It also tries to renew the lease time according to RFC2131
       or RFC1541 (obsolete).

OPTIONS
       -d     With  this  flag	dhcpcd will syslog(LOG_DEBUG,...)
	      messages for about every step it does.  It's recom-
	      mended  to  use this option since it doesn't really
	      produce too much output but will	greatly	 help  in
	      resolving a problems if any.

       -k     Sends  SIGHUP  signal to the dhcpcd process that is
	      currently running. If  dhcpcd  receives  SIGHUP  it
	      will  send  DCHP_RELEASE	message to the server and
	      destroy dhcpcd cache. In	a  case	 dhcpcd	 receives
	      SIGTERM  which is normally used by shutdown(8) when
	      rebooting	 the  system   dhcpcd	will   not   send
	      DHCP_RELEASE  and will not destroy cache. When sys-
	      tem boots dhcpcd will use cache to request the same
	      IP  address  from	 DHCP  server  which was assigned
	      before the system went down.

       -n     Sends SIGALRM signal to the dhcpcd process that  is
	      currently	 running  which	 forces	 dhcpcd to try to
	      renew the lease. If dhcpcd is not running, the flag
	      is  ignored  and	dhcpcd follows the normal startup
	      procedure.

       -r     Makes dhcpcd RFC1541 (obsolete) compliant.   dhcpcd
	      is  RFC2131  compliant unless this option is speci-
	      fied.

       -B     Requests broadcast response from DHCP server.

       -C     Forces dhcpcd to	calculate  checksum  on	 received
	      packets.

       -D     Forces  dhcpcd to set domainname of the host to the
	      domainname  option  supplied  by	DHCP  server.  By
	      default  dhcpcd will NOT set domainname of the host
	      to the domainname option received from DHCP server.

       -H     Forces  dhcpcd  to  set hostname of the host to the
	      hostname	option	supplied  by  DHCP  server.    By
	      default dhcpcd will NOT set hostname of the host to
	      the hostname option received from DHCP server.

       -R     Prevents	  dhcpcd    from    replacing	 existing
	      /etc/resolv.conf file.

       -T     Test  case, when dhcpcd goes through the DHCP nego-
	      tiation sequence but doesn't actually configure the
	      interface	 or otherwise change anything on the sys-
	      tem. Used primarily for testing DHCP servers.

       -t timeout
	      Specifies (in seconds ) for how  long  dhcpcd  will
	      try  to  get  an IP address. The default is 60 sec-
	      onds.  dhcpcd will not fork into	background  until
	      it  gets	a  valid  IP address in which case dhcpcd
	      will return 0 to the parent  process.   In  a  case
	      dhcpcd  times  out  before  receiving  a	valid  IP
	      address from DHCP server dhcpcd  will  return  exit
	      code 1 to the parent process.

       -c filename
	      Deprecated  option  provided for compatibility with
	      dhcpcd v.0.70.  dhcpcd will try to execute filename
	      after it configures the interface.

       -h hostname
	      specifies	 a  string  used  for the hostname option
	      field when dhcpcd sends DHCP  messages.  Some  DHCP
	      servers,	notably	 those	used  by  @Home Networks,
	      require the hostname option field containing a spe-
	      cific string in the DHCP messages from clients.

       -i vendorClassID
	      Specifies	  the  vendor  class  identifier  string.
	      dhcpcd uses the  default	vendor	class  identifier
	      string  (system  name,  system release, and machine
	      type) if it is not specified.

       -I clientID
	      Specifies the  client  identifier	 string.   dhcpcd
	      uses   the   default  client  identifier	(Ethernet
	      Address of the network  interface)  if  it  is  not
	      specified.

       -l leasetime
	      Specifies	 (in  seconds) the recommended lease time
	      to the server. (Note that the server  can	 override
	      this  value  if it sees fit). This value is used in
	      the DHCP_DISCOVER message. The default is	 infinite
	      (0xffffffff).

       -s [ipaddr]
	      Sends  DHCP_INFORM  message  to  DHCP  server using
	      ipaddr.  The optional ipaddr parameter must  be  in
	      the  form	 xxx.xxx.xxx.xxx.  If no ipaddr parameter
	      is given on the command line dhcpcd will use the IP
	      address  currently  assigned  to the interface.  If
	      there is no IP address currently	assigned  to  the
	      interface	 dhcpcd	 will  use previously obtained IP
	      address	stored	  in	/etc/dhcpc/dhcpcd-<inter-
	      face>.cache file.

       -w windowsize
	      Specifies	 the  window  size for the gateway route.
	      Default = 32768.

       interface
	      Specifies the network interface name  (eth0,  eth1,
	      etc.).   dhcpcd  uses  the  network  interface eth0
	      unless an explicit name is specified.


FILES
       /etc/dhcpc
	      directory used for storing files created by dhcpcd

       /etc/dhcpc/dhcpcd-<interface>.info
	      file in which dhcpcd saves  the  host  information.
	      The  word	 interface  is actually replaced with the
	      network interface name like eth0 to which dhcpcd is
	      attached.

       /etc/dhcpc/dhcpcd-<interface>.exe
	      file  which  dhcpcd will try to execute whenever it
	      detects a change in IP address.

       /etc/resolv.conf
	      file created by dhcpcd when the client receives DNS
	      and  domain name options.	 The old /etc/resolv.conf
	      file will be  renamed  to	 /etc/resolv.conf.sv  and
	      will  be	restored  back	when dhcpcd exits for any
	      reason.

       /var/run/dhcpcd-<interface>.pid
	      file containing the process id of dhcpcd.	 The word
	      interface	 is  actually  replaced	 with the network
	      interface	 name  like  eth0  to  which  dhcpcd   is
	      attached.


       /etc/dhcpc/dhcpcd-<interface>.cache
	      Cache  file  containing  the previously assigned IP
	      address and some other things.  The word	interface
	      is  actually  replaced  with  the network interface
	      name like eth0 to which dhcpcd is attached.


SEE ALSO
       Dynamic Host Configuration Protocol, RFC2131  and  RFC1541
       (obsolete)  DHCP	 Options  and  BOOTP  Vendor  Extensions,
       RFC2132


BUGS
       dhcpcd uses time(3)  to	calculate  the	lease  expiration
       time.   If  the system time is changed while the client is
       running, the lease expiration time may not be predictable.

AUTHORS
       v.<1.3
       Yoichi Hariguchi <yoichi@fore.com>
       v.1.3
       Sergei Viznyuk <sv@phystech.com>

dhcpcd 1.3		 31 January 1998			4


