Enable IP Broadcast on Linux Bridge
While packaging minidlna in a Docker container, it became clear that IP Broadcasts (required by minidlna) are not bridged by default in Ubuntu 14.04.
Adding the following file (10-fix-bridge.conf) with the following to /etc/sysctl.d/ fixes this:
# allows broadcasts to reach Docker containers
#net.bridge.bridge-nf-call-arptables = 1
#net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 0