Automatic network configuration

What's very likely the case if the system's network was configured automatically?
If the system's network was configured automatically, it is likely that the system is connected to an Ethernet network with an IPv6 router or DHCP server.

Using DHCP

What does DHCP stand for?
DHCP stands for Dynamic Host Configuration Protocol.

What does Dynamic Host Configuration Protocol (DHCP) assist with?
DHCP assists with network configuration for a variety of parameters.

What parameters can Dynamic Host Configuration Protocol (DHCP) automatically configure?
The parameters that DHCP can automatically configure include:

  • IP address.
  • Network mask.
  • Routes.
  • DNS servers.
  • NTP servers.

What does Dynamic Host Configuration Protocol (DHCP) require?
DHCP requires the server to run on the same Layer 2 (Ethernet) segment as the client requesting a lease.

On what type of network is Dynamic Host Configuration Protocol (DHCP) often used?
The types of network that DHCP is often used on is RFC1918 (private).

What is Dynamic Host Configuration Protocol (DHCP) also often used to acquire?
DHCP is also often used to acquire public information from ISPs.

Does the Gentoo boot media run dhcpcd automatically?
Yes, the Gentoo boot media runs dhcpcd automatically.

How do you disable dhcpcd from running on the Gentoo boot media?
To disable dhcpcd from running automatically on the Gentoo boot media, add the nodhcp argument to the boot media kernel commandline.

How do you start dhcpcd on a particular network interface?
To start dhcpcd on a particular network interface, run:

dhcpcd interface_name

How do you start dhcpcd so that the system uses the hostname and domain name provided by the DHCP server?
To start dhcpcd so that the system uses the hostname and domain name provided by the DHCP server, run:

dhcpcd -HD interface_name

How do you stop dhcpcd?
To stop dhcpcd, run:

dhcpcd -x

Testing the network

How can you check if the default route has been properly configured?
To check if the default route has been properly configured, run:

ip route

What does it mean if there's no default route defined?
If there's no default route defined, that means internet connectivity is unavailable and additional configuration is required.

How can basic internet connectivity be confirmed?
Basic internet connectivity can be confirmed by running:

ping -c 3 1.1.1.1

What should you start pinging instead of a hostname and why?
Instead of a hostname, you should start pinging known IP addresses because this can isolate DNS issues from basic internet connectivity issues.

How can you confirm outbound HTTPS access and DNS resolution?
To confirm outbound HTTPS access and DNS resolution, run:

curl --location gentoo.org --output /dev/null

Unless curl reports an error, or other tests fail, the installation process can ... ... with ... ...
Unless curl reports an error, or other tests fail, the installation process can be continued with disk preparation.

What may need configuration if curl reports an error but internet-bound pings work?
If curl reports an error, but internet-bound pings work, DNS may need configuration.

What should you do first if internet connectivity hasn't been established?
If internet connectivity hasn't been established, you should first verify interface information.

What three things should you do after verifying interface information?
The three things you should do after verifying interface information are:

  1. Using net-setup to assist in network configuration.
  2. Application specific configuration.
  3. Attempting manual network configuration.

Obtaining interface info

What is the first step to getting networking to work if it doesn't already work out of the box?
If networking doesn't already working out of the box, the first step is to enumerate host network interfaces.

What command, belonging to what package, can be used to query and configure system networking?
The command that can query and configure system networking is the ip command belonging to the sys-apps/iproute2 package.

What does the link argument do when used with the ip command?
When used with the ip command, the link argument displays network interface links.

Example of ip link output
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
4: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
    link/ether e8:40:f2:ac:25:7a brd ff:ff:ff:ff:ff:ff

What does the address argument do when used with the ip command?
When used with the ip command, the address argument queries device address information.

Example of ip address output
2: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether e8:40:f2:ac:25:7a brd ff:ff:ff:ff:ff:ff
    inet 10.0.20.77/22 brd 10.0.23.255 scope global enp1s0
       valid_lft forever preferred_lft forever
    inet6 fe80::ea40:f2ff:feac:257a/64 scope link
       valid_lft forever preferred_lft forever

What two things could be happening if no interfaces other than the lo (loopback) are displayed?
If no interfaces other than the lo are displayed, the two things that could be happening are:

  1. The networking hardware is faulty.
  2. The driver for the interface hasn't been loaded into the kernel.