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•
Configure IKE DPD instead of the IKE keepalive feature unless IKE DPD is not supported on
the peer. The IKE keepalive feature sends keepalives at regular intervals, which consumes
network bandwidth and resources.
•
The keepalive timeout time configured on the local device must be longer than the keepalive
interval configured at the peer. Since it seldom occurs that more than three consecutive packets
are lost on a network, you can set the keepalive timeout three times as long as the keepalive
interval.
To configure the IKE keepalive feature:
Step
1.
Enter system view.
2.
Set the IKE SA keepalive
interval.
3.
Set the IKE SA keepalive
timeout time.
Configuring the IKE NAT keepalive feature
If IPsec traffic passes through a NAT device, you must configure the NAT traversal feature. If no
packet travels across an IPsec tunnel in a period of time, the NAT sessions are aged and deleted,
disabling the tunnel from transmitting data to the intended end. To prevent NAT sessions from being
aged, configure the NAT keepalive feature on the IKE gateway behind the NAT device to send NAT
keepalive packets to its peer periodically to keep the NAT session alive.
To configure the IKE NAT keepalive feature:
Step
1.
Enter system view.
2.
Set the IKE NAT keepalive
interval.
Configuring IKE DPD
DPD detects dead peers. It can operate in periodic mode or on-demand mode.
•
Periodic DPD—Sends a DPD message at regular intervals. It features an earlier detection of
dead peers, but consumes more bandwidth and CPU.
•
On-demand DPD—Sends a DPD message based on traffic. When the device has traffic to
send and is not aware of the liveness of the peer, it sends a DPD message to query the status of
the peer. If the device has no traffic to send, it never sends DPD messages. As a best practice,
use the on-demand DPD mode.
The IKE DPD works as follows:
1.
The local device sends a DPD message to the peer, and waits for a response from the peer.
2.
If the peer does not respond within the retry interval specified by the retry seconds parameter,
the local device resends the message.
3.
If still no response is received within the retry interval, the local end sends the DPD message
again. The system allows a maximum of two retries.
4.
If the local device receives no response after two retries, the device considers the peer to be
dead, and deletes the IKE SA along with the IPsec SAs it negotiated.
Command
system-view
ike keepalive interval seconds
ike keepalive timeout seconds
Command
system-view
ike nat-keepalive seconds
296
Remarks
N/A
By default, no keepalives are sent
to the peer.
By default, IKE SA keepalive
never times out.
Remarks
N/A
The default interval is 20 seconds.
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Troubleshooting
