Arch Linux has depreciated the usage of net-tools in /etc/rc.conf in favor of
iproute2. The new syntax in /etc/rc.conf makes it simple to setup a single
interface though anything complicated is best done through netcfg. I didn't
really want to use netcfg for my main workstation as it's network setup never
changes and it seemed like overkill. Unfortunately I did need to configure IPv6
related settings and this was no longer easily done in rc.conf. The two items I
needed to set were the IPv6 address and the interface MTU. (If I don't set an
MTU of 1280-1480 I have trouble with my IPv6 tunnel.)
I decided to remove the IPv6 address setting completely and rely on radvd running on my router. This took care of my workstation's IPv6 address and default route. I really should have done this earlier.
I started patching the /etc/rc.d/network script to take an mtu variable but
started to have second thoughts. Most users would not need it and it seemed a
shame to complicate the network_up() function. There was a good chance the
patch would not be accepted. In the end I just added the line:
ip link set dev eth0 mtu 1280
to /etc/rc.local. This worked fine.