Linux From Scratch - Version cross-la-r11.0-228-systemd

Chapter 7. Booting the Target System and Building Additional Temporary Tools

7.13. Setting Up Loopback Network Interface with IPRoute-5.14.0

The IPRoute2 package contains programs for basic and advanced IPV4-based networking. Now we need ip from it to bring up loopback network interface, which is expected by the testsuites of various packages.

Approximate build time: less than 0.1 SBU
Required disk space: 15 MB

7.13.1. Use IPRoute2 to Set Up Loopback Network Interface

IPRoute2 package has several dependencies not installed yet, but we only need ip utility from the package now. Disable the build of other utilities: 

sed '/SUBDIRS/s/=.*/=lib ip/' -i Makefile

Compile the package: 

PKG_CONFIG=false make

The meaning of the environment variable:

PKG_CONFIG=false

The building system attempts to find dependencies with pkg-config, which is not installed yet. We can override it since ip utility does not need these dependencies.

It's not needed to install the ip utility now. Just bring up the loopback interface: 

ip/ip link set lo up

Verify the result: 

ip/ip addr

The command above should show 127.0.0.1/8 as the IPv4 address of lo, and ::1/128 as the IPv6 address.

Details on this package are located in Section 8.61.2, “Contents of IPRoute2.”