Dhcpcd

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Dynamic Host Configuration Protocol Client Daemon (net-misc/dhcpcd) is a popular DHCP client capable of handling both IPv4 and IPv6 configuration.

Installation

USE flags

USE flags for net-misc/dhcpcd A fully featured, yet light weight RFC2131 compliant DHCP client

+embedded	Embed the definitions of dhcp options in the dhcpcd executable
+udev	Enable virtual/udev integration (device discovery, power and storage device support, etc)
debug	Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces
ipv6	Add support for IP version 6
privsep	Enable support for privilege separation

Data provided by the Gentoo Package Database · Last update: 2024-11-03 16:28 More information about USE flags

Emerge

Use the following command to install dhcpcd:

root #emerge --ask net-misc/dhcpcd

Configuration

Files

All dhcpcd configuration can be set in the /etc/dhcpcd.conf file, but for most installations dhcpcd will work out of the box presuming most computers nowadays are behind a router or access point running a DHCP server. Though man 5 dhcpcd.conf will be helpful in case advanced configuration is required.

Static IP addresses

In case the network interface card should be configured with a static IP address, add their data to /etc/dhcpcd.conf. The following is an example of manually adding a static address, routes, and DNS by editing DHCPCD's configuration file using a text editor of choice:

FILE /etc/dhcpcd.conf

static ip_address=192.168.0.10/24
static routers=192.168.0.1
static domain_name_servers=192.168.0.1

IPv6 Prefix Request

FILE /etc/dhcpcd.confRequest a prefix for eth0.lan to be routed publicly with eth0.wan.

# Disable router solicitations for all interfaces, enable only for selected ones
noipv6rs
 
# Interface configuration for the ''wan'' vlan on the ''eth0'' interface
interface eth0.wan
  # Enable router solicitation for this interface
  ipv6rs
  # Request a normal address usins ''iaid'' 1 for interface ''eth0.wan''
  ia_na 1
  # Request a prefix using ''iaid'' 2 and assign it to the ''eth0.lan'' interface using ''sla_id'' 0
  ia_pd 2 eth0.lan/0

Usage

Invocation

root #dhcpcd --help

usage: dhcpcd	[-146ABbDdEGgHJKLMNPpqTV]
		[-C, --nohook hook] [-c, --script script]
		[-e, --env value] [-F, --fqdn FQDN] [-f, --config file]
		[-h, --hostname hostname] [-I, --clientid clientid]
		[-i, --vendorclassid vendorclassid] [-j, --logfile logfile]
		[-l, --leasetime seconds] [-m, --metric metric]
		[-O, --nooption option] [-o, --option option]
		[-Q, --require option] [-r, --request address]
		[-S, --static value]
		[-s, --inform address[/cidr[/broadcast_address]]]
 [--inform6]		[-t, --timeout seconds] [-u, --userclass class]
		[-v, --vendor code, value] [-W, --whitelist address[/cidr]] [-w]
		[--waitip [4 | 6]] [-y, --reboot seconds]
		[-X, --blacklist address[/cidr]] [-Z, --denyinterfaces pattern]
		[-z, --allowinterfaces pattern] [--inactive] [interface] [...]
       dhcpcd	-n, --rebind [interface]
       dhcpcd	-k, --release [interface]
       dhcpcd	-U, --dumplease interface
       dhcpcd	--version
       dhcpcd	-x, --exit [interface]

Run it as a service

See Network management using DHCPCD.

One-time DHCP

To configure a network interface for one-time DHCP use issue the following command:

root #dhcpcd eth0

Be sure to replace eth0 in the command above with the appropriate network interface name.

Renew a lease

To renew the lease on eth0, --rebind or -n can be used:

root #dhcpcd -n eth0

Release a lease

To release a lease on eth0, --release or -k can be used:

root #dhcpcd -k eth0

Troubleshooting

• dhcpcd not working for IPv6 (#CONFIG_PACKET is not set)
• If /etc/resolv.conf does not update with VPN's DNS, consider installing net-dns/openresolv.

See also

• The Handbook's recommendations on handling network interfaces
• Netifrc — Gentoo's default framework for configuring and managing network interfaces on systems running OpenRC.
• Network management using DHCPCD — explains how to use dhcpcd for complete network stack management.

External resources

• Dhcpcd on the Arch Wiki
• Forums post: No Internet access when update to dhcpcd 6.10.0
• DHCP on Wikipedia
• RFC 2131 - Dynamic Host Configuration Protocol