Currently Coova Chilli does a great job of automatically selecting the upstream (or WAN) interface if it’s not specified in the config file. Unfortunately, if you don’t have a downstream (LAN) interface specified in the config file (with HS_LAN) then chilli will fail to start.

Placing the following in the config file in place of the HS_LAN=ethx spot will auto select the first unused ethernet network card.

HS_LANIF=$(cat /proc/net/dev|grep -o eth.|grep -v $(route -n|grep '^0.0.0.0'|head -n1|awk '{print $8}') | head -n1)