In /etc/init.d/network:runip(), 'ip address add "$@" dev "$int"' is called, but iproute does not by default bring that link up. Hence, you end up with addressed interfaces but no link or route (which is automatically added when the link goes up). You need to add a call to do the following as well: ip link set "$int" up That would also be the appropriate time to set a requested MTU.
Created attachment 207231 [details] fix-iproute2.patch All, this patch will fix the runip function as described in the previous comment. Also it shows an example of how to use the ifup_ethx variable to set an MTU for an interface using iproute2.
http://roy.marples.name/projects/openrc/changeset/fdca530d4fe159e086ca0ac1d6e4f188ddcc3fad http://roy.marples.name/projects/openrc/changeset/da08e3822fda548e39473b6ad4e5c18c55ca7bc0