Draytek Vigor 3220 SERIES User Manual page 82

Available settings are explained as follows:
Item
Enable / Disable
Keep WAN Connection
WAN Connection
Detection
70
Description
Click Enable for activating this function. If you click Disable,
this function will be closed and all the settings that you
adjusted in this page will be invalid.
Normally, this function is designed for Dynamic IP
environments because some ISPs will drop connections if
there is no traffic within certain periods of time. Check
Enable PING to keep alive box to activate this function.
PING to the IP - If you enable the PING function, please
specify the IP address for the system to PING it for keeping
alive.
PING Interval - Enter the interval for the system to execute
the PING operation.
Such function allows you to verify whether network
connection is alive or not through ARP Detect or Ping Detect.
Mode – Choose ARP Detect or Ping Detect or Always On for
the system to execute for WAN detection. If you choose Ping
Detect as the detection mode, you have to type required
settings for the following items.

Primary/Secondary Ping IP – If you choose Ping Detect as
detection mode, you have to type Primary or Secondary IP
address in this field for pinging.

Ping Gateway IP – If you choose Ping Detect as detection
mode, you also can enable this setting to use current WAN
gateway IP address for pinging. With the IP address(es)
pinging, Vigor router can check if the WAN connection is
on or off.

TTL (Time to Live) – Set TTL value of PING operation.
Vigor2832 Series User's Guide