wiki / software / dhcpcd Edit this page
Edited (1aca415) at 2020-06-10 by Dylan Araps
DHCPCD [0]
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Dynamic Host Configuration Protocol Client Daemon is a popular DHCP client
capable of handling both IPv4 and IPv6 configuration.
Dynamic IP Configuration
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Begin by first verifying that you have dhcpcd installed:
+------------------------------------------------------------------------------+
| |
| $ kiss b dhcpcd && kiss i dhcpcd |
| |
+------------------------------------------------------------------------------+
Once installed, dhcpcd can be used to automatically configure a network device
interface:
+------------------------------------------------------------------------------+
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| $ dhcpcd INTERFACE |
| |
+------------------------------------------------------------------------------+
Remember to replace INTERFACE in the command above with the name of the device
that you wish to configure.
A network device's interface status can be inspected via ip-link:
+------------------------------------------------------------------------------+
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| $ ip link show dev INTERFACE |
| |
+------------------------------------------------------------------------------+
ip-link can also be used to enable or disable an interface:
+------------------------------------------------------------------------------+
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| $ ip link set INTERFACE down # disable the interface |
| $ ip link set INTERFACE up # enable the interface |
| |
+------------------------------------------------------------------------------+
Static IP Configuration
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Continuing from the previous section, we can use ip-address to display the
current DHCP address information:
+------------------------------------------------------------------------------+
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| $ ip address show |
| |
+------------------------------------------------------------------------------+
Using the output of the previous command, add the following lines to the
/etc/dhcpcd.conf file using your preferred text editor:
+------------------------------------------------------------------------------+
| |
| interface INTERFACE |
| static ip_address=STATIC_IP |
| static routers=GATEWAY |
| static domain_name_servers=DNS_SERVER |
| |
+------------------------------------------------------------------------------+
Remember to replace the INTERFACE, STATIC_IP, GATEWAY and DNS_SERVER in the
block above with your own parameters.
Hostname
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A system's hostname can be set by simply creating a /etc/hostname file:
+------------------------------------------------------------------------------+
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| $ echo "HOSTNAME" > /etc/hostname |
| |
+------------------------------------------------------------------------------+
Remember to replace HOSTNAME with the string of your choosing.
Note: Valid characters for hostnames include ASCII letters from A to Z, digits
from 0 to 9, and the hyphen character (-). A hostname may not start with
a hyphen.
Managed via runsv
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Busybox's runsv can be used to create a new managed service with the following
command:
+------------------------------------------------------------------------------+
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| $ ln -s /etc/sv/dhcpcd/ /var/service |
| |
+------------------------------------------------------------------------------+
To start the new managed service, use the following command:
+------------------------------------------------------------------------------+
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| $ sv up dhcpcd |
| |
+------------------------------------------------------------------------------+
Tips and Tricks
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* A list of possible INTERFACE names can be obtained by running the following:
+----------------------------------------------------------------------------+
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| $ ls /sys/class/net |
| |
+----------------------------------------------------------------------------+
* The ping command can be used to verify connectivity with a network device
interface:
+----------------------------------------------------------------------------+
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| $ ping www.google.com |
| |
+----------------------------------------------------------------------------+
* Some network administrators require that the hostname and domain name provided
by the DHCP server is used by the system. In that case, pass the "-HD" switch:
+----------------------------------------------------------------------------+
| |
| $ dhcpcd -HD INTERFACE |
| |
+----------------------------------------------------------------------------+
* If you are not sure what to put in the STATIC_IP, GATEWAY and DNS_SERVER, you
can use the following example for reference:
+----------------------------------------------------------------------------+
| |
| interface eth0 |
| static ip_address=192.168.0.4/24 |
| static routers=192.168.0.1 |
| static domain_name_servers=192.168.0.1 |
| |
+----------------------------------------------------------------------------+
Notice the "/24" suffix, which is an abbreviation for the subnet mask
255.255.255.0. Also, GATEWAY and DNS_SERVER are the same in this example.
References
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[0] https://github.com/rsmarples/dhcpcd
[1] https://wiki.archlinux.org/index.php/Network_configuration
[2] https://wiki.gentoo.org/wiki/Dhcpcd
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Dylan Araps (C) 2019-2020
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