If a sip phone is connected to lan port the firewall open a "udp redirect port 5060 IN from anybody" Our sip local phone only open a udp 5060 connection to to 91.194.96.33 (not to every body) This 45.

The C6 answer to another ip for wan port in case on unicast flood the switch forget the mac address of 185.8.66.90 and act like a hub. and there for it hangs the C6 for severals seconds Legacy ping fr