User Guide
Vigor2910 Series User’s Guide 
98 
Idle Timeout: The default value is 300 seconds. If the 
connection has been idled over the value, the router will drop 
the connection. 
Enable PING to keep alive  This function is to help the router to determine the status of 
IPSec VPN connection, especially useful in the case of 
abnormal VPN IPSec tunnel disruption. For details, please 
refer to the note below. Check to enable the transmission of 
PING packets to a specified IP address. 
PING to the IP  Enter the IP address of the remote host that located at the 
other-end of the VPN tunnel. 
Enable PING to Keep Alive is used to handle abnormal 
IPSec VPN connection disruption. It will help to provide 
the state of a VPN connection for router’s judgment of 
redial. 
Normally, if any one of VPN peers wants to disconnect 
the connection, it should follow a serial of packet 
exchange procedure to inform each other. However, if the 
remote peer disconnect without notice, Vigor router will 
by no where to know this situation. To resolve this 
dilemma, by continuously sending PING packets to the 
remote host, the Vigor router can know the true existence 
of this VPN connection and react accordingly. This is 
independent of DPD (dead peer detection). 
ISDN  Build ISDN LAN-to-LAN connection to remote network. You 
should set up Link Type and identity like User Name and 
Password for the authentication of remote server. You can 
further set up Callback (CBCP) function below. This feature is 
useful for i model only. 
PPTP  Build a PPTP VPN connection to the server through the 
Internet. You should set the identity like User Name and 
Password below for the authentication of remote server. 
IPSec Tunnel  Build an IPSec VPN connection to the server through Internet. 
L2TP with …  Build a L2TP VPN connection through the Internet. You can 
select to use L2TP alone or with IPSec. Select from below: 
None: Do not apply the IPSec policy. Accordingly, the VPN 
connection employed the L2TP without IPSec policy can be 
viewed as one pure L2TP connection. 
Nice to Have: Apply the IPSec policy first, if it is applicable 
during negotiation. Otherwise, the dial-out VPN connection 
becomes one pure L2TP connection. 
Must: Specify the IPSec policy to be definitely applied on the 
L2TP connection. 
User Name  This field is applicable when you select ISDN, PPTP or L2TP 
with or without IPSec policy above. 
Password  This field is applicable when you select ISDN, PPTP or L2TP 
with or without IPSec policy above. 
PPP Authentication  This field is applicable when you select ISDN, PPTP or L2TP 
with or without IPSec policy above. PAP/CHAP is the most 
common selection due to wild compatibility. 










