Provided by: dhcpcd5_6.0.5-2build0.14.04.1_amd64 bug


     dhcpcd.conf — dhcpcd configuration file


     Although dhcpcd can do everything from the command line, there are cases where it's just
     easier to do it once in a configuration file.  Most of the options found in dhcpcd(8) can be
     used here.  The first word on the line is the option and the rest of the line is the value.
     Leading and trailing whitespace for the option and value are trimmed.  You can escape
     characters in the value using the \ character.

     Blank lines and lines starting with # are ignored.

     Here's a list of available options:

     allowinterfaces pattern
             When discovering interfaces, the interface name must match pattern which is a space
             or comma separated list of patterns passed to fnmatch(3).  If the same interface is
             matched in denyinterfaces then it is still denied.

     denyinterfaces pattern
             When discovering interfaces, the interface name must not match pattern which is a
             space or comma separated list of patterns passed to fnmatch(3).

     arping address [address]
             dhcpcd will arping each address in order before attempting DHCP.  If an address is
             found, we will select the replying hardware address as the profile, otherwise the ip
             address.  Example:

                   interface bge0

                   static ip_address=

             Background immediately.  This is useful for startup scripts which don't disable link
             messages for carrier status.

     blacklist address[/cidr]
             Ignores all packets from address[/cidr].

     whitelist address[/cidr]
             Only accept packets from address[/cidr].  blacklist is ignored if whitelist is set.

             Instructs the DHCP server to broadcast replies back to the client.  Normally this is
             only set for non Ethernet interfaces, such as FireWire and InfiniBand.  In most
             cases, dhcpcd will set this automatically.

     env value
             Push value to the environment for use in dhcpcd-run-hooks(8).  For example, you can
             force the hostname hook to always set the hostname with env force_hostname=YES.

             If the hostname is set, will be will set to the FQDN if possible as per RFC 4702
             section 3.1.  If the FQDN option is missing, dhcpcd will still try and set a FQDN
             from the hostname and domain options for consistency.  To override this, set env
             hostname_fqdn=[YES|NO|SERVER].  A value of server means just what the server says,
             don't manipulate it.  This could lead to an inconsistent hostname on a DHCPv4 and
             DHCPv6 network where the DHCPv4 hostname is short and the DHCPv6 has an FQDN.
             DHCPv6 has no hostname option.

     clientid string
             Send the clientid.  If the string is of the format 01:02:03 then it is encoded as
             hex.  For interfaces whose hardware address is longer than 8 bytes, or if the
             clientid is an empty string then dhcpcd sends a default clientid of the hardware
             family and the hardware address.

     duid    Generate an RFC 4361.  compliant clientid.  If persistent storage is available then
             a DUID-LLT (link local address + time) is generated, otherwise DUID-LL is generated
             (link local address).  The DUID-LLT generated will be held in /etc/dhcpcd.duid and
             should not be copied to other hosts.

     fallback profile
             Fallback to using this profile if DHCP fails.  This allows you to configure a static
             profile instead of using ZeroConf.

     hostname name
             Sends hostname to the DHCP server so it can be registered in DNS.  If hostname is an
             empty string then the current system hostname is sent.  If hostname is a FQDN (ie,
             contains a .) then it will be encoded as such.

             Sends the short hostname to the DHCP server instead of the FQDN.  This is useful
             because DHCP servers will not register the FQDN in their DNS if the domain part does
             not match theirs.

             Also, see the env option above to control how the hostname is set on the host.

     ia_na [iaid]
             Request a DHCPv6 Normal Address for iaid.  If none is specified, a default iaid is
             used.  If the interface name is 4 characters or less then that is used, otherwise
             the interface index is used.

     ia_ta [iaid]
             Request a DHCPv6 Temporary Address for iaid.

     ia_pd [iaid [interface [/ sla_id [/ prefix_len]]]]
             Request a DHCPv6 Delegated Prefix for iaid.  If no interface is given then we will
             assign a prefix to every other interface with a unique sla_id for each, starting
             from 0.  Otherwise addresses are only assigned for each interface and sla_id A
             default prefix_len of 64 is assumed.  sla_id is an integer and is added to the
             prefix which must fit inside prefix_len less the length of the delegated prefix.
             You can specify multiple interface / sla_id / prefix_len per ia_pd, space separated.
             IPv6RS should be disabled globally when requesting a Prefix Delegation like so:


                   interface eth0
                   ia_pd 1 eth1/0 eth2/1

             Only configure IPv4.

             Only confgiure IPv6.

     fqdn [disable | ptr | both]
             ptr just asks the DHCP server to update the PTR record of the host in DNS whereas
             both also updates the A record.  disable will disable the FQDN option.  The default
             is both.  dhcpcd itself never does any DNS updates.  dhcpcd encodes the FQDN
             hostname as specified in RFC1035.

     interface interface
             Subsequent options are only parsed for this interface.

             By default, when dhcpcd receives an IPv6 RA, dhcpcd will only fork to the background
             if the RA contains at least one unexpired RDNSS option.  Set this option so to make
             dhcpcd always fork on an RA.

             Disables kernel IPv6 Router Advertisment processing so dhcpcd can manage addresses
             and routes.  This does not work reliably on any BSD system, probably due to kernel

             Each time dhcpcd receives an IPv6 Router Adveristment, dhcpcd will manage the
             default route only.  This allows dhcpcd to prefer an interface for outbound traffic
             based on metric and/or user selection rather than the kernel.  This does work
             reliably on BSD systems.

     ipv6rs  Enables IPv6 Router Advertisment solicitation.  This is on by default, but is
             documented here in the case where it is disabled globally but needs to be enabled
             for one interface.

     leasetime seconds
             Request a leasetime of seconds.

     metric metric
             Metrics are used to prefer an interface over another one, lowest wins.  dhcpcd will
             supply a default metric of 200 + if_nametoindex(3).  An extra 100 will be added for
             wireless interfaces.

             IPv4 addresses added will overwrite a pre-existing address instead of working

     noarp   Don't send any ARP requests.  This also disables IPv4LL.

             Don't install any default routes.

     nohook script
             Don't run this hook script.  Matches full name, or prefixed with 2 numbers
             optionally ending with .sh.

             So to stop dhcpcd from touching your DNS or MTU settings you would do:-
                   nohook resolv.conf, mtu

             Don't attempt to obtain an IPv4LL address if we failed to get one via DHCP.  See RFC

             Disable solicitation and receipt of IPv6 Router Advertisements.

     nolink  Don't receive link messages about carrier status.  You should only set this for
             buggy interface drivers.

     option option
             Requests the option from the server.  It can be a variable to be used in
             dhcpcd-run-hooks(8) or the numerical value.  You can specify more options separated
             by commas, spaces or more option lines.  Prepend dhcp6_ to option to request a
             DHCPv6 option.  DHCPv4 options are mapped to DHCPv6 where applicable.

     nooption option
             Remove the option from the DHCP message.  This should only be used when a DHCP
             server sends a non requested option that should not be processed.

     destination option
             If dhcpcd.conf detects an address added to a point to point interface (PPP, TUN,
             etc) then it will set the listed DHCP options to the destination address of the

     profile name
             Subsequent options are only parsed for this profile name.

     quiet   Suppress any dhcpcd output to the console, except for errors.

     reboot seconds
             Allow reboot seconds before moving to the DISCOVER phase if we have an old lease to
             use.  The default is 5 seconds.  A setting of 0 seconds causes dhcpcd to skip the
             REBOOT phase and go straight into DISCOVER.  This is desirable for mobile users
             because if you change from network A to network B and they use the same subnet and
             the address from network A isn't in use on network B, then the DHCP server will
             remain silent even if authorative which means dhcpcd will timeout before moving back
             to the DISCOVER phase.

             dhcpcd will release the lease prior to stopping the interface.

     require option
             Requires the option to be present in all DHCP messages, otherwise the message is
             ignored.  It can be a variable to be used in dhcpcd-run-hooks(8) or the numerical
             value.  You can specify more options separated by commas, spaces or more require
             lines.  To enforce that dhcpcd only responds to DHCP servers and not BOOTP servers,
             you can require dhcp_message_type.

     script script
             Use script instead of the default /lib/dhcpcd/dhcpcd-run-hooks.

     ssid ssid
             Subsequent options are only parsed for this wireless ssid.

     static value
             Configures a static value.  If you set ip_address then dhcpcd will not attempt to
             obtain a lease and just use the value for the address with an infinite lease time.

             Here is an example which configures a static address, routes and dns.
                   interface eth0
                   static ip_address=
                   static routers=
                   static domain_name_servers=

             Here is an example for PPP which gives the destination a default route.  It uses the
             special destination keyword to insert the destination address into the value.
                   interface ppp0
                   static ip_address=
                   destination routers

     timeout seconds
             The default timeout for waiting for a DHCP response is 30 seconds which may be too
             long or too short and can be changed here.  A setting of 0 seconds causes dhcpcd to
             wait forever to get a lease.

     userclass string
             Tag the DHCP messages with the userclass.  You can specify more than one.

     vendor code,value
             Add an encapsulated vendor option.  code should be between 1 and 254 inclusive.  To
             add a raw vendor string, omit code but keep the comma.  Examples.

             Set the vendor option 01 with an IP address.
                   vendor 01,
             Set the vendor option 02 with a hex code.
                   vendor 02,01:02:03:04:05
             Set the vendor option 03 with an IP address as a string.
                   vendor 03,\"\"
             Set un-encapsulated vendor option to hello world.
                   vendor ,"hello world"

     vendorclassid string
             The default is dhcpcd-<version>:<os>:<machine>:<platform>.  For example
             If not set then none is sent.  Some badly configured DHCP servers reject unknown
             vendorclassids.  To work around it, try and impersonate Windows by using the MSFT

     waitip  Wait for an address to be assigned before forking to the background.

             Use the last four bytes of the hardware address as the DHCP xid instead of a
             randomly generated number.


     dhcpcd-run-hooks(8), dhcpcd(8), if_nametoindex(3), fnmatch(3)


     Roy Marples <>


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