Has anyone got this Firewall recipe to work
"For a firewall to support LwM2M , it should be configured to allow outgoing UDP packets to destination port 5683 (other ports can be configured), and a llow incoming UDP packets back to the source address/port of the outgoing UDP packet for a period of at least 240 seconds."
from section 8.2.1. at this URL
The first part is easy, but the incoming packets?
We are looking for IPTABLES recipes, but any positive experience with ANY firewall will be helpful.