HP 6125XLG R2306-HP 6125XLG Blade Switch Security Configuration Guide - Page 239

Configuring the IKE NAT keepalive function, Configuring IKE DPD

Page 239 highlights

• Configure IKE DPD instead of the IKE keepalive function unless IKE DPD is not supported on the peer. The IKE keepalive function sends keepalives at regular intervals, which consumes network bandwidth and resources. • The keepalive timeout time configured at the local 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 function: Step 1. Enter system view. 2. Set the IKE SA keepalive interval. 3. Set the IKE SA keepalive timeout time. Command system-view ike keepalive interval seconds ike keepalive timeout seconds Remarks N/A By default, no keepalives are sent to the peer. By default, IKE SA keepalive never times out. Configuring the IKE NAT keepalive function If IPsec traffic passes through a NAT device, you must configure the NAT traversal function. 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 function 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 function: Step 1. Enter system view. 2. Set the IKE NAT keepalive interval. Command system-view ike nat-keepalive seconds Remarks N/A The default interval is 20 seconds. 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. This mode is recommended. 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 send the DPD message again. The system allows a maximum of two retries. 230

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230
Configure IKE DPD instead of the IKE keepalive function unless IKE DPD is not supported on the peer.
The IKE keepalive function sends keepalives at regular intervals, which consumes network
bandwidth and resources.
The keepalive timeout time configured at the local 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 function:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Set the IKE SA keepalive
interval.
ike keepalive interval
seconds
By default, no keepalives are sent
to the peer.
3.
Set the IKE SA keepalive
timeout time.
ike keepalive timeout
seconds
By default, IKE SA keepalive never
times out.
Configuring the IKE NAT keepalive function
If IPsec traffic passes through a NAT device, you must configure the NAT traversal function. 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 function 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 function:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Set the IKE NAT keepalive
interval.
ike nat-keepalive
seconds
The default interval is 20 seconds.
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. This mode is recommended.
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 send the DPD message again. The
system allows a maximum of two retries.