blog/source/_posts/2014-02-08-internet-sharing-ipv4-and-ipv6-on-archlinux-using-dnsmasq.markdown

layout	title	date	comments	categories
post	Internet sharing (ipv4 and ipv6) on archlinux using dnsmasq	2014-02-08 20:02:22 +0100	true	arch dhcp ipv6 router advertisement network

Update: Added adhoc wlan network

A guide to connect with a different machine using a ethernet cable for internet sharing or just transferring files:

1. Install dnsmasq and iproute2

   $ pacman -S dnsmasq iproute2

2. Copy over the configuration files at the end of the article and edit the /etc/conf.d/share-internet@<device> to match your network setup. (where <device> is your network device)

3. Start the sharing service with systemd

   $ sudo systemctl start internet-sharing@.service

After that the other machine can connect via dhcp. It will get an ipv4 address from the 10.20.0.0/24 subnet and a ipv6 address from the fd21:30c2:dd2f:: subnet. Your host will be reachable via 10.20.0.1 or fd21:30c2:dd2f::1. Thanks to ipv6 router advertising, an AAAA record for each host is automatically set based on the hostname. This means if your hostname is foo, all members of the network can just connect to it using the address foo. You should disable the share-internet.service, if you don't need it. Otherwise you might mess up network setups, if you connect to a network with the device on which the dhcp service is running.

Happy networking!

{% include_code /etc/systemd/system/share-internet.service lang:ini share-internet/share-internet.service %}

{% include_code /etc/dnsmasq.conf lang:ini share-internet/dnsmasq.conf %}

Ethernet to Wlan:

{% include_code /etc/conf.d/share-internet@enp0s25 lang:bash share-internet/share-internet@enp0s25 %}

Wlan to Ethernet:

If you have luck and your wifi driver is capable of the infrastructure mode, you should take a look at hostadp, in my case I have to create an adhoc network. To enable the adhoc network:

$ sudo systemctl enable wireless-adhoc@<device>.service

{% include_code /etc/conf.d/share-internet@wlp3s0 lang:bash share-internet/share-internet@wlp3s0 %}

{% include_code /etc/systemd/system/wireless-adhoc@.service lang:ini share-internet/wireless-adhoc@.service %}

{% include_code /etc/wpa_supplicant/wpa_supplicant-adhoc-wlp3s0.conf lang:bash share-internet/wpa_supplicant-adhoc-wlp3s0.conf %}