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[ScreenOS] How to configure the Source Interface and Destination IP options of VPN Monitor



Article ID: KB9503 KB Last Updated: 15 Feb 2021Version: 7.0

The VPN is in the Active/Down state when the VPN Monitor is down. Some possible reasons for the VPN Monitor down condition are:

  • Remote VPN connection is configured to block ICMP echo requests.

  • Remote VPN connection is a third-party product that does not respond to ICMP echo requests.

When configuring the VPN Monitor, consider the following:

  • When VPN Monitor is enabled and a source interface is not chosen, the Firewall device uses the outgoing interface as the default.

  • When VPN Monitor is enabled and a destination IP address is not specified, the Firewall device uses the IP address for the remote gateway.

This article provides the steps to configure the source interface and destination IP address options for the VPN Monitor.


  • VPN Monitor is Down.

  • VPN status shows Active/Down.



Configure VPN Monitor to use the Source interface and Destination IP address options. 

To configure these options in the WebUI, perform the following:

  1. Select VPNs > Autokey IKE.

  2. Edit the appropriate VPN, and click on the Advanced button at the bottom of the screen.  

This will take you to the Advanced settings screen. The VPN Monitor settings are at the bottom of the page. 


  1. Set the Destination IP to an internal host in the remote peer’s LAN that responds to ICMP echo requests. Also, the remote peer’s firewall must have a policy permitting the ICMP echo requests of VPN Monitor to pass through it. 

For more information, refer to the Source Interface and Destination Address and Policy Consideration sections of the following manual:
Concepts & Examples ScreenOS Reference Guide​ Version 6.3.0
  1. Source Interface: Select the interface to be used as the source interface for VPN monitor packets. For VPN monitoring through NetScreen Remote, the source interface for VPN monitor packets must be bound to the Trust zone of the network being monitored.

  2. Optimized: Select this check box if you want the Juniper Firewall device to accept incoming traffic through the VPN tunnel as a substitute for ICMP echo replies. If there is both incoming and outgoing traffic through the VPN tunnel, the device suppresses VPN monitoring pings.


To configure the above options in CLI, enter the following command:

set vpn <vpn_name> monitor source-interface <interface> destination-ip <ip_addr> optimized [rekey]


Modification History:

2017-12-23: Article reviewed for accuracy. Older hyperlinks replaced by 6.3.0 CNE. Article is correct and complete.

2021-02-15: Article reviewed for accuracy, article is correct and complete.


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