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Function Specification
|
Rekey
Connection Type
Rekey Method
Enable
On-demand
connection
Perform rekey when encrypted communication using the generated SA
exists.
No Rekey
On-demand
connection
Perform rekey regardless of the presence of the encrypted communication
using the generated SA.
Always
Continuous
connection
Perform rekey when there is encrypted communication using the
generated SA.
[Relationship of IKE SA and IPsec SA]
IKE SA is created for sending and receiving controlled packets to establish and maintain an IPsec tunnel, while IPsec
SA is created for sending and receiving the actual encrypted data using IKE SA.
[Rekey]
Rekey is performed to preserve the confidentiality of the communication path, and generate a new SA. After rekeying,
it communicates with the new SA. After the lifetime expires, the old SA is deleted.
[Specification of source and corresponding destination]
To create an IPsec tunnel, specify the IP address of the corresponding destination. Source IP address is automatically
selected.
[IPsec Operation Mode]
There are two kinds of operation modes, "policy based" and "route based".
Policy based
IPsec communication is performed only for communications that satisfy the policy set on the
IPsec setting screen
Route based
It creates a tunnel interface for IPsec and communicates with IPsec according to the routing
setting of that interface.
The initial value on IPsec setting screen is policy based. Cloud service connections use route based.
[Fragmentation methods]
When IP packets are encrypted through IPsec, its length becomes longer than the original length. Because of this,
fragments might be generated during the actual transmission. There are two methods of fragmentation, “pre-
fragment” method where it is encrypted after fragmentation, and “post-fragment” method where it is fragmented
after encryption. The initial value on IPsec setting screen is "post-fragment" method.
For cloud service connection, it is as follows:
Amazon Web Service
“
post-fragment
”
method
Microsoft Azure (Route Based)
“
pre-fragment
”
method
Microsoft Azure (Policy Based)
“
pre-fragment
”
method
[Retransmission of IKE control packet]
IKE monitors the control sequence and retransmits the IKE control packet when the sequence does not progress
normally.