Draytek Vigor 3220 SERIES User Manual page 90

Available settings are explained as follows:
Item
WAN Connection
Detection
Below shows an example for successful IPv6 connection based on PPP mode.
Info
78
Description
Such function allows you to verify whether network
connection is alive or not through Ping Detect.
Mode – Choose Always On or Ping Detect for the system to
execute for WAN detection. Always On means no detection
will be executed. The network connection will be on always.

Ping IP/Hostname – If you choose Ping Detect as
detection mode, you have to type IP address in this field
for pinging.

TTL (Time to Live) –If you choose Ping Detect as
detection mode, you have to type TTL value.
At present, the IPv6 prefix can be acquired via the PPPoE mode connection which is
Vigor2832 Series User's Guide