NetScreen Technologies NetScreen-10 Series, Руководство по установке

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When in Network Address Translation (NAT) mode, the NetScreen device
translates two components in the header of an outgoing IP packet traversing the
firewall from the Trusted side: its source IP address and source port number. The
NetScreen device replaces the source IP address of the host that sent the packet
with the IP address of the Untrusted port
1
of the NetScreen device. Also, it
replaces the source port number with another random port number generated by
the NetScreen device.
When the reply packet arrives at the NetScreen device, the device translates two
components in the IP header of the incoming packet: the destination address and
port number, which are translated back to the original numbers. The packet is
then forwarded to its destination.
1. If the outbound traffic is destined for the DMZ, then the source IP address is translated to that of
the DMZ port.
Private Address
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Public Address
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