dhcpcd is an implementation of the DHCP client specified in RFC2131. A DHCP client is useful for connecting your computer to a network which uses DHCP to assign network addresses. dhcpcd strives to be a fully featured, yet very lightweight DHCP client.
![[Note]](../images/note.png)
Development versions of BLFS may not build or run some packages properly if LFS or dependencies have been updated since the most recent stable versions of the books.
Download (HTTP): https://github.com/NetworkConfiguration/dhcpcd/releases/download/v10.3.0/dhcpcd-10.3.0.tar.xz
Download MD5 sum: 07d4b32791b52bc49d2a1677c7a2804e
Download size: 276 KB
Estimated disk space required: 3.2 MB (with tests)
Estimated build time: less than 0.1 SBU (with tests)
LLVM-21.1.8 (with Clang), ntp-4.2.8p18, chronyd, and ypbind
Recent releases of dhcpcd optionally support privilege separation. As the practical security benefits of this are unclear for a program like dhcpcd and the setup is more complicated, the book currently defaults to disable it.
If you however would like to use privilege separation, additional
installation steps are necessary to set up the proper environment.
Issue the following commands as the root user:
install -v -m700 -d /var/lib/dhcpcd &&
groupadd -g 52 dhcpcd &&
useradd -c 'dhcpcd PrivSep' \
-d /var/lib/dhcpcd \
-g dhcpcd \
-s /bin/false \
-u 52 dhcpcd &&
chown -v dhcpcd:dhcpcd /var/lib/dhcpcd
Build dhcpcd without privilege separation by running the following command:
./configure --prefix=/usr \
--sysconfdir=/etc \
--libexecdir=/usr/lib/dhcpcd \
--dbdir=/var/lib/dhcpcd \
--runstatedir=/run \
--disable-privsep &&
make
Alternatively, build dhcpcd with privilege separation by running the following commands:
./configure --prefix=/usr \
--sysconfdir=/etc \
--libexecdir=/usr/lib/dhcpcd \
--dbdir=/var/lib/dhcpcd \
--runstatedir=/run \
--privsepuser=dhcpcd &&
make
To test the results, issue: make test.
Now, as the root user:
make install
--libexecdir=/usr/lib/dhcpcd: This
switch sets a better location for the dhcpcd internal libraries.
--dbdir=/var/lib/dhcpcd:
This switch adjusts the database directory because the default
directory, /var/db, is not
FHS-compliant.
--runstatedir=/run: This
switch sets the runtime state directory because the default
/var/run is a symbolic link to
/run, and using /var/run is deprecated.
--disable-privsep: This
switch disables privilege separation, which is the default in
dhcpcd. This switch is not used in the build configuration where
privilege separation is used.
--privsepuser=dhcpcd: This
switch sets the privilege separation user in the build
configuration where privilege escalation is used.
--with-hook=...: You can optionally
install more hooks, for example to install some configuration files
such as ntp.conf. A set of hooks can
be found in the dhcpcd-hooks
directory in the build tree.
To configure dhcpcd, you need to first
install the OpenRC service for it, then make a few edits to it as
the root user:
install -vDm755 /dev/stdin /etc/init.d/dhcpcd << "EOF" &&
#!/sbin/openrc-run
# Starts the dhcpcd daemon.
# Authors: Zeckma - zeckma.tech@gmail.com
# Version: LFS 12.5
description="starts dhcpcd"
command=/sbin/dhcpcd
pidfile=/var/run/dhcpcd.pid
command_args="-B -q ${dhcpcd_options} ${iface}"
command_background=yes
depend() {
provide net
need localmount
use logger
after bootmisc modules
before dns
}
EOF
rc-update add dhcpcd default
The default
for dhcpcd is to
set the hostname and mtu. It also overwrites /etc/resolv.conf and /etc/ntp.conf. These modifications to system
files are done by hooks which are stored in /usr/lib/dhcpcd/dhcpcd-hooks. You can change
this behavior by removing or adding hooks from/to that
directory. The execution of hooks can be disabled by using the
--nohook (-C) command line option or by the nohook option in the /etc/dhcpcd.conf file.
The service
needs a corrosponding configuration file made for it. Create one
now as the root user:
cat > /etc/conf.d/dhcpcd << "EOF"
iface="<interface>"
dhcpcd_options=""
EOF
Replace <interface>eth0, wlo1, or
something else. Run ip
addr for a full list of interfaces. If an
interface you want isn't available, it may be because the
interface needs kernel drivers built for it or the drivers tried
to load firmware that was not built into the kernel or wasn't
present on the system at boot time.
Although not
usual, it is possible that you need to configure dhcpcd to use a fixed ip. Here, we give an
example. As the root user, add to
the /etc/dhcpcd.conf configuration
file using the following commands. Adjust appropriately for
additional interfaces and for the actual ip and router you need:
cat >> /etc/dhcpcd.conf << "EOF"
static ip_address=192.168.0.10/24
static routers=192.168.0.1
static domain_name_servers=192.168.0.1
EOF
You can either use DNS servers in /etc/resolv.conf from another system, your
preferred servers, or just the example /etc/resolv.conf.head file below as is:
cat > /etc/resolv.conf.head << "EOF"
# OpenDNS servers
nameserver 208.67.222.222
nameserver 208.67.220.220
EOF