dhcpcd-7.0.8

Introduction to dhcpcd

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.

This package is known to build and work properly using an LFS-8.3 platform.

Package Information

dhcpcd Dependencies

Optional

llvm (with Clang)

User Notes: http://wiki.linuxfromscratch.org/blfs/wiki/dhcpcd

Installation of dhcpcd

Install dhcpcd by running the following commands:

./configure --libexecdir=/lib/dhcpcd \
            --dbdir=/var/lib/dhcpcd  &&
make

This package does not come with a test suite.

Now, as the root user:

make install

Command Explanations

--libexecdir=/lib/dhcpcd: The default /libexec is not FHS-compliant. Since this directory may need to be available early in the boot, /usr/libexec cannot be used either.

--dbdir=/var/lib/dhcpcd: The default /var/db is not FHS-compliant

--with-hook=...: You can optionally install more hooks, for example to install some configuration files such as ntp.conf. The set of hooks is in the dhcpcd-hooks directory in the build tree.

Configuring dhcpcd

Config Files

/etc/dhcpcd.conf

General Configuration Information

To configure dhcpcd, you need to first install the network service script, /lib/services/dhcpcd included in the blfs-bootscripts-20180105 package (as user root):

make install-service-dhcpcd

Whenever dhcpcd configures or shuts down a network interface, it executes hook scripts. For more details about those scripts, see the dhcpcd-run-hooks and dhcpcd man pages.

Finally, as the root user create the /etc/sysconfig/ifconfig.eth0 configuration file using the following commands. Adjust appropriately for additional interfaces:

cat > /etc/sysconfig/ifconfig.eth0 << "EOF"
ONBOOT="yes"
IFACE="eth0"
SERVICE="dhcpcd"
DHCP_START="-b -q <insert appropriate start options here>"
DHCP_STOP="-k <insert additional stop options here>"
EOF

For more information on the appropriate DHCP_START and DHCP_STOP values, examine the man page for dhcpcd.

[Note]

Note

The default behavior of dhcpcd sets the hostname and mtu settings. It also overwrites /etc/resolv.conf and /etc/ntp.conf. These modifications to system files and settings on system configuration files are done by hooks which are stored in /lib/dhcpcd/dhcpcd-hooks. Setup dhcpcd 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.

Review the dhcpcd man page for switches to add to the DHCP_START value.

Configuration Information: fixed ip (System V versions of LFS)

Although not usual, it is possible that you need to configure dhcpcd to use a fixed ip. Here we give an example for the System V versions of LFS. As the root user create the /etc/sysconfig/ifconfig.eth0 configuration file using the following commands. Adjust appropriately for additional interfaces and for the actual ip and router you need:

cat > /etc/sysconfig/ifconfig.eth0 << "EOF"
ONBOOT="yes"
IFACE="eth0"
SERVICE="dhcpcd"
DHCP_START="-b -q -S ip_address=192.168.0.10/24 -S routers=192.168.0.1"
DHCP_STOP="-k"
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

General Configuration Information for systemd versions of LFS

If you want to configure network interfaces at boot using dhcpcd, you need to install the systemd unit included in blfs-systemd-units-20180105 package by running the following command as the root user:

make install-dhcpcd

Whenever dhcpcd configures or shuts down a network interface, it executes hook scripts. For more details about those scripts, see the dhcpcd-run-hooks and dhcpcd man pages.

[Note]

Note

The default behavior of dhcpcd sets the hostname and mtu settings. It also overwrites /etc/resolv.conf and /etc/ntp.conf. These modifications to system files and settings on system configuration files are done by hooks which are stored in /lib/dhcpcd/dhcpcd-hooks. Setup dhcpcd 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.

[Note]

Note

Make sure that you disable the systemd-networkd service or configure it not to manage the interfaces you want to manage with dhcpcd.

At this point you can test if dhcpcd is behaving as expected by running the following command as the root user:

systemctl start dhcpcd@eth0

To start dhcpcd on a specific interface at boot, enable the previously installed systemd unit by running the following command as the root user:

systemctl enable dhcpcd@eth0

Replace eth0 with the actual interface name.

Contents

Installed Program: dhcpcd
Installed Library: /lib/dhcpcd/dev/udev.so
Installed Directory: /{,var/}lib/dhcpcd and /usr/share/dhcpcd

Short Descriptions

dhcpcd

is an implementation of the DHCP client specified in RFC2131.

udev.so

add udev support for interface arrival and departure; this is because udev likes to rename the interface, which it can't do if dhcpcd grabs it first.

Last updated on 2018-09-22 16:32:07 -0700