dhcpcd - a wrapper for the DHCP client daemon.

In Debian, the DHCP client daemon binary is called dhcpcd-bin and it is invoked via a wrapper called dhcpcd. Dhcpcd is normally invoked by ifup(8) but ifup only allows the setting of a limited number of dhcpcd command line flags. The dhcpcd wrapper reads extra flags from /etc/dhcpc/config and then invokes dhcpcd-bin(8) It also adds the hostname as an argument to the command line, unless it is already set by ifup or /etc/dhcpc/config or SET_HOSTNAME is configured. In that case there is no point in sending the old hostname with the DHCP request when it will be overridden by a new name supplied by the DHCP server.

Version: 1:2.0.3-1

dhcpcd     [-dknoprBCDHNRSTY]     [-t <timeout>]    [-c <ExecFilePath>]
     [-h <hostname>]        [-i <vendorClassID>]        [-I <clientID>]
     [-l <leasetime>]  [-s [ipaddr]]  [-F none|ptr|both] [-G [gateway]]
     [-w <windowsize>]          [-L <ConfigDir>]          [-e <etcDir>]
     [-m <routeMetric>] [interface]

It gets the host information (IP address, netmask, broadcast 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.

V: dhcpcd 2.0, 20 July 2005

/etc/dhcpc/dhcpcd.exe
       script  file,  which dhcpcd will try to execute whenever it con-
       figures or brings down the interface.  The  path  to  this  exe-
       cutable  script  can  be changed with -c  <ExecFilePath> option.
       Dhcpcd passes 3 parameters to dhcpcd.exe script:

dhcpcd.exe <HostInfoFilePath> <up|down|new> [-d]
       The first parameter <HostInfoFilePath> is path to dhcpcd-<inter-
       face>.info  file. The word <interface> is actually replaced with
       interface name dhcpcd is attached to, e.g.  "eth0".  The  second
       parameter  values  <up|down|new>  mean  the  interface  has been
       brought up with the same IP address as before  ("up"),  or  with
       the  new  IP  address ("new"), or the interface has been brought
       down ("down"). Parameter -d is passed in a case dhcpcd has  been
       started with -d debug flag.

documented on: 2006.07.22