vpn interface keepalive—Configure how often a GRE interface sends keepalive packets (on vEdge routers only). The sending of keepalive packets is enabled by default.
Because GRE tunnels are stateless, the sending of keepalive packets is the only way to determine whether the remote end of the tunnel is up. The keepalive packets are looped back to the sender. Receipt of these packets by the sender indicates that the remote end of the GRE tunnel is up.
In Releases 17.1 and later, GRE interfaces behind a NAT device send keepalive messages. If you configure an IP address for the GRE interface, it is that address that sends the keepalive messages.
If the vEdge router sits behind a NAT and you have configured GRE encapsulation, you must disable keepalives. To do this, include a keepalive 0 0 command in the configuration. You cannot disable keepalives by issuing a no keepalive command. This command returns the keepalive to its default settings.
vManage Feature Template
For vEdge routers only:
Configuration ► Templates ► VPN Interface GRE
Configuration ► Templates ► VPN Interface PPP Ethernet
- Keepalive Time
How often the GRE interface sends keepalive packets on the GRE tunnel.
Range: 0 through 65535 seconds
Default: 10 seconds
- Keepalive Retries
How many times the GRE interface tries to resend keepalive packets before declaring the remote end of the GRE tunnel to be down. With the default keepalive time of 10 seconds and the default retry of 3 times, if the router receives no looped-back keepalive packets from the remote end of the GRE tunnel, the tunnel would be declared to be down after 40 seconds.
Range: 0 through 255
Configure the keepalive time for a GRE tunnel:
vEdge(config-vpn-0)# interface gre1 vEdge(config-interface-gre1)# keepalive 60 10 vEdge(config-interface-gre1)# show full configuration vpn 0 interface gre1 ip address 10.0.111.11/24 keepalive 60 10 tunnel-source 10.0.5.11 tunnel-destination 220.127.116.11 no shutdown ! !
Command introduced in Viptela Software Release 15.4.1.
In Release 17.1, add support for GRE interfaces to send keepalive messages.