Setting The Nat Keepalive Timer; Configuring A Dpd Detector; Disabling Next Payload Field Checking - HP 12500 Series Configuration Manual

Setting the NAT keepalive timer

If IPsec traffic needs to pass through NAT security gateways, you must configure the NAT traversal
function. If no packet travels across an IPsec tunnel in a certain period of time, the NAT mapping may get
aged and be deleted, disabling the tunnel beyond the NAT gateway from transmitting data to the
intended end. To prevent NAT mappings from being aged, an ISAKMP SA behind the NAT security
gateway sends NAT keepalive packets to its peer at a certain interval to keep the NAT session alive.
To set the NAT keepalive timer:
Step
1. Enter system view.
2. Set the NAT keepalive
interval.

Configuring a DPD detector

DPD irregularly detects dead IKE peers. It works as follows:
When the local end sends an IPsec packet, it checks the time the last IPsec packet was received
1.
from the peer.
If the time interval exceeds the DPD interval, it sends a DPD hello to the peer.
2.
If the local end receives no DPD acknowledgement within the DPD packet retransmission interval,
3.
it retransmits the DPD hello.
If the local end still receives no DPD acknowledgement after having made the maximum number of
4.
retransmission attempts (two by default), it considers the peer already dead, and clears the IKE SA
and the IPsec SAs based on the IKE SA.
DPD enables an IKE entity to check the liveliness of its peer only when necessary. It generates less traffic
than the keepalive mechanism, which exchanges messages periodically.
To configure a DPD detector:
Step
1. Enter system view.
Create a DPD detector and
2.
enter its view.
3. Set the DPD interval.
4. Set the DPD packet
retransmission interval.

Disabling next payload field checking

The Next payload field is in the generic payload header of the last payload of the IKE negotiation
message (the message comprises multiple payloads). According to the protocol, this field must be 0 if the
Command
system-view
ike sa nat-keepalive-timer interval
seconds
Command
system-view
ike dpd dpd-name
interval-time interval-time
time-out time-out
203
Remarks
N/A
20 seconds by default.
Remarks
N/A
N/A
Optional.
10 seconds by default.
Optional.
5 seconds by default.