Download Configuring NAT

Office Mode Solution
IP Address Lease duration
When a remote user’s machine is assigned an IP address, that machine can use it
for a certain amount of time. This time period is referred to as the “IP address
lease duration.” The remote client automatically asks for a lease renewal after half
of the IP lease duration period has elapsed. Hence, if the IP lease duration time is
set to 60 minutes, a renewal request will be sent after 30 minutes. If a renewal is
granted, the client will request a renewal again after 30 minutes and so on. If the
renewal fails, the client attempts again after half of the remaining time, e.g. 15
minutes, then 7.5 minutes, etc. If no renewal is granted and the 60 minutes of the
lease duration times out, the tunnel link terminates. To renew the connection the
remote user must reconnect to the gateway. Upon reconnection, an IKE
renegotiation is initiated and a new tunnel created.
When the IP address is allocated from a predefined IP pool on the gateway, the
gateway determines the IP lease duration period, default being 15 minutes.
When using a DHCP server to assign IP addresses to users, the DHCP server’s
configuration determines the IP lease duration. When a user disconnects and
reconnects to the gateway within a short period of time, it is likely that the user will
get the same IP address as before.
Using name resolution - WINS and DNS
To facilitate access of a remote user to resources on the internal network, the
administrator can specify WINS and DNS servers for the remote user. This
information is sent to the remote user during IKE config mode along with the IP
address allocation information, and is used by the remote user’s operating system
for name-to-IP resolution when the user is trying to access the organization’s
internal resources.
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