| DHCPCD(8) | System Manager's Manual | DHCPCD(8) | 
dhcpcd —
| dhcpcd | [ -146ABbDdEGgHJKLMNPpqTV]
      [-C,--nohookhook] [-c,--scriptscript] [-e,--envvalue] [-F,--fqdnFQDN] [-f,--configfile] [-h,--hostnamehostname] [-I,--clientidclientid] [-i,--vendorclassidvendorclassid] [-j,--logfilelogfile] [-l,--leasetimeseconds] [-m,--metricmetric] [-O,--nooptionoption] [-o,--optionoption] [-Q,--requireoption] [-r,--requestaddress] [-S,--staticvalue] [-s,--informaddress[/cidr[/broadcast_address]]]
      [--inform6]
      [-t,--timeoutseconds] [-u,--userclassclass] [-v,--vendorcode, value]
      [-W,--whitelistaddress[/cidr]]
      [-w]
      [--waitip=[4 | 6]]
      [-y,--rebootseconds] [-X,--blacklistaddress[/cidr]]
      [-Z,--denyinterfacespattern] [-z,--allowinterfacespattern]
      [--inactive]
      [--configure]
      [--noconfigure]
      [interface] [...] | 
| dhcpcd | -n,--rebind[interface] | 
| dhcpcd | -k,--release[interface] | 
| dhcpcd | -U,--dumplease[interface] | 
| dhcpcd | --version | 
| dhcpcd | -x,--exit[interface] | 
dhcpcd is an implementation of the DHCP client specified
  in RFC 2131. dhcpcd gets the
  host information (IP address, routes, etc) from a DHCP server and configures
  the network interface of the machine on which it is
  running. dhcpcd then runs the configuration script
  which writes DNS information to
  resolvconf(8), if available,
  otherwise directly to /etc/resolv.conf. If the
  hostname is currently blank, (null) or localhost, or
  force_hostname is YES or TRUE or 1 then
  dhcpcd sets the hostname to the one supplied by the
  DHCP server. dhcpcd then daemonises and waits for the
  lease renewal time to lapse. It will then attempt to renew its lease and
  reconfigure if the new lease changes when the lease begins to expire or the
  DHCP server sends a message to renew early.
If any interface reports a working carrier then
    dhcpcd will try to obtain a lease before forking to
    the background, otherwise it will fork right away. This behaviour can be
    modified with the -b,
    --background and
    -w,
    --waitip options.
dhcpcd is also an implementation of the
    BOOTP client specified in RFC 951.
dhcpcd is also an implementation of the
    IPv6 Router Solicitor as specified in RFC 4861 and
    RFC 6106.
dhcpcd is also an implementation of the
    IPv6 Privacy Extensions to AutoConf as specified in RFC
    4941. This feature needs to be enabled in the kernel and
    dhcpcd will start using it.
dhcpcd is also an implementation of the
    DHCPv6 client as specified in RFC 3315. By default,
    dhcpcd only starts DHCPv6 when instructed to do so
    by an IPV6 Router Advertisement. If no Identity Association is configured,
    then a Non-temporary Address is requested.
dhcpcd failed to obtain a lease, it probes for a
  valid IPv4LL address (aka ZeroConf, aka APIPA). Once obtained it restarts the
  process of looking for a DHCP server to get a proper address.
When using IPv4LL, dhcpcd nearly always
    succeeds and returns an exit code of 0. In the rare case it fails, it
    normally means that there is a reverse ARP proxy installed which always
    defeats IPv4LL probing. To disable this behaviour, you can use the
    -L,
    --noipv4ll option.
dhcpcd only works with those interfaces, otherwise
  dhcpcd discovers available Ethernet interfaces that
  can be configured. When dhcpcd not limited to one
  interface on the command line, it is running in Manager mode. The
  dhcpcd-ui project expects dhcpcd to be running this
  way.
If a single interface is given then dhcpcd
    only works for that interface and runs as a separate instance to other
    dhcpcd processes. -w,
    --waitip option is enabled
    in this instance to maintain compatibility with older versions. Using a
    single interface also affects the -k,
    -N, -n and
    -x options, where the same interface will need to be
    specified, as a lack of an interface will imply Manager mode which this is
    not. To force starting in Manager mode with only one interface, the
    -M,
    --manager option can be
    used.
Interfaces are preferred by carrier, DHCP lease/IPv4LL and then
    lowest metric. For systems that support route metrics, each route will be
    tagged with the metric, otherwise dhcpcd changes the
    routes to use the interface with the same route and the lowest metric. See
    options below for controlling which interfaces we allow and deny through the
    use of patterns.
Non-ethernet interfaces and some virtual ethernet interfaces such
    as TAP and bridge are ignored by default, as is the FireWire interface. To
    work with these devices they either need to be specified on the command
    line, be listed in
    --allowinterfaces or have an
    interface directive in /etc/dhcpcd.conf.
dhcpcd runs
  /libexec/dhcpcd-run-hooks, or the script specified by
  the -c,
  --script option. This script
  runs each script found in /libexec/dhcpcd-hooks in a
  lexical order. The default installation supplies the scripts
  01-test, 02-dump,
  20-resolv.conf and
  30-hostname. You can disable each script by using the
  -C,
  --nohook option. See
  dhcpcd-run-hooks(8)
  for details on how these scripts work. dhcpcd
  currently ignores the exit code of the script.
More scripts are supplied in
    /usr/share/dhcpcd/hooks and need to be copied to
    /libexec/dhcpcd-hooks if you intend to use them. For
    example, you could install 29-lookup-hostname so
    that dhcpcd can lookup the hostname of the IP
    address in DNS if no hostname is given by the lease and one is not already
    set.
dhcpcd with the
  following options:
-b,
    --background-c,
    --script
    script-D,
    --duid
    [ll | lt |
    uuid | value]-I,
      --clientid. The DUID
      generated will be held in /var/db/dhcpcd/duid and
      should not be copied to other hosts. This file also takes precedence over
      the above rules except for setting a value.-d,
    --debug-E,
    --lastleasedhcpcd cannot obtain a lease, then try to use
      the last lease acquired for the interface.--lastleaseextenddhcpcd will give it up if any other host tries to
      claim it for their own via ARP. This violates RFC 2131, section 3.7, which
      states the lease should be dropped once it has expired.-e,
    --env
    value-e
    force_hostname=YES.-g,
    --reconfiguredhcpcd will re-apply IP address, routing and run
      dhcpcd-run-hooks(8)
      for each interface. This is useful so that a 3rd party such as PPP or VPN
      can change the routing table and / or DNS, etc and then instruct
      dhcpcd to put things back afterwards.
      dhcpcd does not read a new configuration when this
      happens - you should rebind if you need that functionality.-F,
    --fqdn
    fqdndhcpcd itself never does any DNS
      updates. dhcpcd encodes the FQDN hostname as
      specified in RFC 1035.-f,
    --config
    filedhcpcd
      always processes the config file before any command line options.-h,
    --hostname
    hostname-I,
    --clientid
    clientiddhcpcd sends a default
      clientid of the hardware family and the hardware
      address.-i,
    --vendorclassid
    vendorclassid-j,
    --logfile
    logfiledhcpcd still writes to
      syslog(3). The
      logfile is reopened when
      dhcpcd receives the
      SIGUSR2 signal.-k,
    --release
    [interface]dhcpcd process running on
      the interface to release its lease and de-configure
      the interface regardless of the
      -p,
      --persistent option. If no
      interface is specified then this applies to all
      interfaces in Manager mode. If no interfaces are left running,
      dhcpcd will exit.-l,
    --leasetime
    secondsdhcpcd does not request any lease time and leaves
      it in the hands of the DHCP server.-M,
    --managerdhcpcd in Manager mode even if only one
      interface specified on the command line. See the Multiple Interfaces
      section above.-m,
    --metric
    metricdhcpcd will supply a default metric of 1000 +
      if_nametoindex(3).
      This will be offset by 2000 for wireless interfaces, with additional
      offsets of 1000000 for IPv4LL and 2000000 for roaming interfaces.-n,
    --rebind
    [interface]dhcpcd to reload its configuration and
      rebind the specified interface. If no
      interface is specified then this applies to all
      interfaces in Manager mode. If dhcpcd is not
      running, then it starts up as normal.-N,
    --renew
    [interface]dhcpcd to renew existing addresses on the
      specified interface. If no
      interface is specified then this applies to all
      interfaces in Manager mode. If dhcpcd is not
      running, then it starts up as normal. Unlike the
      -n,
      --rebind option above, the
      configuration for dhcpcd is not reloaded.-o,
    --option
    option-p,
    --persistentdhcpcd normally de-configures the
      interface and configuration when it exits.
      Sometimes, this isn't desirable if, for example, you have root mounted
      over NFS or SSH clients connect to this host and they need to be notified
      of the host shutting down. You can use this option to stop this from
      happening.-r,
    --request
    address-s,
    --inform
    address[/cidr[/broadcast_address]]-r,
      --request as above, but
      sends a DHCP INFORM instead of DISCOVER/REQUEST. This does not get a lease
      as such, just notifies the DHCP server of the
      address in use. You should also include the optional
      cidr network number in case the address is not
      already configured on the interface. dhcpcd
      remains running and pretends it has an infinite lease.
      dhcpcd will not de-configure the interface when it
      exits. If dhcpcd fails to contact a DHCP server
      then it returns a failure instead of falling back on IPv4LL.--inform6dhcpcd is not processing IPv6RA messages and the
      need for DHCPv6 Information Request exists.-S,
    --static
    valueip_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.
You cannot presently set static DHCPv6 values. Use the
        -e,
        --env option
      instead.
-t,
    --timeout
    secondsdhcpcd to wait forever to get a lease. If
      dhcpcd is working on a single interface then
      dhcpcd will exit when a timeout occurs, otherwise
      dhcpcd will fork into the background.-u,
    --userclass
    class-v,
    --vendor
    code,valueSet the vendor option 01 with an IP address.
--versiondhcpcd then exits before doing any
    configuration.-w--waitip=[4 | 6]dhcpcd will wait for any address protocol to be
      assigned. It is possible to wait for more than one address protocol and
      dhcpcd will only fork to the background when all
      waiting conditions are satisfied.-x,
    --exit
    [interface]dhcpcd process
      running on the interface to exit. If no
      interface is specified, then the above is applied to
      all interfaces in Manager mode. See the -p,
      --persistent option to
      control configuration persistence on exit, which is enabled by default in
      dhcpcd.conf(5).
      dhcpcd then waits until this process has
    exited.-y,
    --reboot
    secondsdhcpcd to skip the reboot phase and go straight
      into discover. This has no effect on DHCPv6 other than skipping the reboot
      phase.dhcpcd will try to do as much as it can by default.
  However, there are sometimes situations where you don't want the things to be
  configured exactly how the DHCP server wants. Here are some options that deal
  with turning these bits off.
Note that when dhcpcd is restricted to a
    single interface then the interface also needs to be specified when asking
    dhcpcd to exit using the commandline. If the
    protocol is restricted as well then the protocol needs to be included with
    the exit instruction.
-1,
    --oneshot-w,
      --waitip option to specify
      which protocol(s) to configure before exiting.-4,
    --ipv4only-6,
    --ipv6only-A,
    --noarp-B,
    --nobackground-C,
    --nohook
    scriptSo to stop dhcpcd from touching your
        DNS settings you would do:-
-G,
    --nogateway-H,
    --xidhwaddr-J,
    --broadcastdhcpcd will set
      this automatically.-K,
    --nolinkdhcpcd through a network manager.-L,
    --noipv4ll-O,
    --nooption
    option-P,
    --printpidfiledhcpcd
      will use based on commmand-line arguments to stdout.-Q,
    --require
    optiondhcpcd only responds to DHCP servers and not BOOTP
      servers, you can -Q
      dhcp_message_type.-q,
    --quietdhcpcd on the command line, only warnings
      and errors will be displayed. If this option is used another time then all
      console output is disabled. These messages are still logged via
      syslog(3).-T,
    --testdhcpcd.-U,
    --dumplease
    [interface]-4 or -6
      flags to specify an address family. If a lease is piped in via standard
      input then that is dumped. In this case, specifying an address family is
      mandatory.-V,
    --variables-W,
    --whitelist
    address[/cidr]-X,
      --blacklist is ignored if
      -W,
      --whitelist is set.-X,
    --blacklist
    address[/cidr]-Z,
    --denyinterfaces
    pattern-z,
    --allowinterfaces
    pattern-Z,
      - -denyinterfaces then it
      is still denied.--inactivedhcpcd to be started in Manager mode
      and then wait for subsequent dhcpcd commands to
      start each interface as required.--configuredhcpcd to configure the system. This is the
      default behaviour and sets
    if_configured=true.--noconfiguredhcpcd will not configure the system at all. This
      is only of use if the
      --script that
      dhcpcd calls at each network event configures the
      system instead. This is different from -T,
      --test mode in that it's
      not one shot and the only change to the environment is the addition of
      if_configured=false.--nodevdhcpcd is marked as
  STATIC or INFORM without an address then dhcpcd will
  monitor the interface until an address is added or removed from it and act
  accordingly. For point to point interfaces (like PPP), a default route to its
  destination is automatically added to the configuration. If the point to point
  interface is configured for INFORM, then dhcpcd
  unicasts INFORM to the destination, otherwise it defaults to STATIC.
dhcpcd requires a Berkley Packet Filter, or BPF device
  on BSD based systems and a Linux Socket Filter, or LPF device on Linux based
  systems for all IPv4 configuration.
If restricting dhcpcd to a single
    interface and optionally address family via the command-line then all
    further calls to dhcpcd to rebind, reconfigure or
    exit need to include the same restrictive flags so that
    dhcpcd knows which process to signal.
Some DHCP servers implement ClientID filtering. If
    dhcpcd is replacing an in-use DHCP client then you
    might need to adjust the clientid option dhcpcd
    sends to match. If using a DUID in place of the ClientID, edit
    /var/db/dhcpcd/duid accordingly.
-C,
      --nohook option described
      above.dhcpcd running on all
      interfaces.dhcpcd running on the
      interface.| August 23, 2021 | NetBSD 10.0 |