With laptops, systems can be always on the move. As a result, the system may not always have an Ethernet cable or plugged in or an access point available. Also, the user may want networking to automatically work when an Ethernet cable is plugged in or an access point is found.
In this chapter, we cover how this can be done.
This document only talks about ifplugd, but there are alternatives such as netplug. netplug is a lightweight alternative to ifplugd, but it relies on the kernel network drivers working correctly, and many drivers do not.
ifplugd is a daemon that starts and stops interfaces when an Ethernet cable is inserted or removed. It can also manage detecting association to Access Points or when new ones come in range.
emerge --ask sys-apps/ifplugd
Configuration for ifplugd is fairly straightforward too. The configuration is held in /etc/conf.d/net. Run man ifplugd for details on the available variables. Also, see /usr/share/doc/netifrc-*/net.example.bz2 for more examples.
# Replace eth0 with the interface to be monitored ifplugd_eth0="..." # To monitor a wireless interface ifplugd_eth0="--api-mode=wlan"
In addition to managing multiple network connections, users may want to add a tool that makes it easy to work with multiple DNS servers and configurations. This is very handy when the system receives its IP address via DHCP.
emerge --ask net-dns/openresolv
See man resolvconf to learn more about its features.