User's Manual

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* This mechanism is used in coordination with the refreshing of NAT bindings. Specifically, in conjunction with use of Restricted Cone
NAT or Port Restricted Cone NAT (as may be configured in some gateways). A device’s internal address / port mappings, which the
STUN protocol is allowed to make use of, can have keep alive values attributed. These minimum and maximum keep alive times
define respectively, the minimum time to retain the mapping information STUN has discovered, and the maximum time to retain
that information, before refreshing it through forced re-discovery.
With the above-mentioned NAT schemes, it is possible the network address translation initially established may not be used after a
specified elapsed time. Such internal mapping is dropped. The gateway will then assign a different address mapping. This mech-
anism within the STUN protocol allows for coordinated refresh on the bindings for mappings it uses. For further information, review
STUN-related RFCs.
Selecting appropriate values for these two fields are influenced by a variety of environmental factors including devices types
deployed, services employed and NAT configuration options enabled within the topology.
Internet Time
On this page, you can synchronize the clock in your gateway with reliable external clocking servers available on the Internet.
1. In the left navigation bar, click Management > Internet Time. The following page appears.