dhcpcd-run-hooks - DHCP client configuration script - man(8) - [phpMan]

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DHCPCD-RUN-HOOKS(8) System Manager's Manual DHCPCD-RUN-HOOKS(8)

NAME
dhcpcd-run-hooks — DHCP client configuration script

DESCRIPTION
dhcpcd-run-hooks is used by dhcpcd(8) to run any system and user defined hook scripts. Sys‐
tem hook scripts are found in /usr/lib/dhcpcd/dhcpcd-hooks and the user defined hooks are
/etc/dhcpcd.enter-hook. and /etc/dhcpcd.exit-hook. The default install supplies hook
scripts for configuring /etc/resolv.conf and the hostname. Your distribution may have in‐
cluded other hook scripts to say configure ntp or ypbind. A test hook is also supplied that
simply echos the dhcp variables to the console from DISCOVER message.

The hooks scripts are loaded into the current shell rather than executed in their own
process. This allows each hook script, such as /etc/dhcpcd.enter-hook to customise environ‐
ment variables or provide alternative functions to hooks further down the chain. As such,
using the shell builtins exit, exec or similar will cause dhcpcd-run-hooks to exit at that
point.

Each time dhcpcd-run-hooks is invoked, $interface is set to the interface that dhcpcd is run
on and $reason is set to the reason why dhcpcd-run-hooks was invoked. DHCP information to be
configured is held in variables starting with the word new_ and old DHCP information to be
removed is held in variables starting with the word old_. dhcpcd can display the full list
of variables it knows about by using the -V, --variables argument.

Here's a list of reasons why dhcpcd-run-hooks could be invoked:

PREINIT dhcpcd is starting up and any pre-initialisation required should be per‐
formed now.

CARRIER dhcpcd has detected the carrier is up. This is generally just a notifica‐
tion and no action need be taken.

NOCARRIER dhcpcd lost the carrier. The cable may have been unplugged or association
to the wireless point lost.

NOCARRIER_ROAMING
dhcpcd lost the carrier but the interface configuration is persisted. The
OS has to support wireless roaming or IP Persistence for this to happen.

INFORM | INFORM6 dhcpcd informed a DHCP server about its address and obtained other configu‐
ration details.

BOUND | BOUND6 dhcpcd obtained a new lease from a DHCP server.

RENEW | RENEW6 dhcpcd renewed its lease.

REBIND | REBIND6 dhcpcd has rebound to a new DHCP server.

REBOOT | REBOOT6 dhcpcd successfully requested a lease from a DHCP server.

DELEGATED6 dhcpcd assigned a delegated prefix to the interface.

IPV4LL dhcpcd obtained an IPV4LL address, or one was removed.

STATIC dhcpcd has been configured with a static configuration which has not been
obtained from a DHCP server.

3RDPARTY dhcpcd is monitoring the interface for a 3rd party to give it an IP ad‐
dress.

TIMEOUT dhcpcd failed to contact any DHCP servers but was able to use an old lease.

EXPIRE | EXPIRE6 dhcpcd's lease or state expired and it failed to obtain a new one.

NAK dhcpcd received a NAK from the DHCP server. This should be treated as EX‐
PIRE.

RECONFIGURE dhcpcd has been instructed to reconfigure an interface.

ROUTERADVERT dhcpcd has received an IPv6 Router Advertisement, or one has expired.

STOP | STOP6 dhcpcd stopped running on the interface.

STOPPED dhcpcd has stopped entirely.

DEPARTED The interface has been removed.

FAIL dhcpcd failed to operate on the interface. This normally happens when
dhcpcd does not support the raw interface, which means it cannot work as a
DHCP or ZeroConf client. Static configuration and DHCP INFORM is still al‐
lowed.

TEST dhcpcd received an OFFER from a DHCP server but will not configure the in‐
terface. This is primarily used to test the variables are filled correctly
for the script to process them.

ENVIRONMENT
dhcpcd will clear the environment variables aside from $PATH. The following variables will
then be set, along with any protocol supplied ones.

$interface the name of the interface.

$protocol the protocol that triggered the event.

$reason as described above.

$pid the pid of dhcpcd.

$ifcarrier the link status of $interface: unknown, up or down.

$ifmetric $interface preference, lower is better.

$ifwireless 1 if $interface is wireless, otherwise 0.

$ifflags $interface flags.

$ifmtu $interface MTU.

$ifssid the SSID the interface is connected to.

$interface_order A list of interfaces, in order of preference.

$if_up true if the interface is up, otherwise false. This is more than
IFF_UP and may not be equal.

$if_down true if the interface is down, otherwise false. This is more
than IFF_UP and may not be equal.

$af_waiting Address family waiting for, as defined in dhcpcd.conf(5).

$profile the name of the profile selected from dhcpcd.conf(5).

$new_delegated_dhcp6_prefix space-separated list of delegated prefixes.

FILES
When dhcpcd-run-hooks runs, it loads /etc/dhcpcd.enter-hook, any scripts found in
/usr/lib/dhcpcd/dhcpcd-hooks in lexical order, then finally /etc/dhcpcd.exit-hook.

man > dhcpcd-run-hooks(8)