Nokia M11 T66220, User Manual

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Nokia M11 User’s Manual
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Copyright Nokia Networks Oy C33833001SE_00 6-4
6.4.1 Pinhole
The basic NAPT functionality does not allow access from the Internet
to a host on LAN because the private addresses cannot be seen outside
the router. In order to support access from the global Internet to a server
on a private subnet, the static NAPT mapping is used. In M11 this
functionality is called pinhole.
In the static mapping, the WAN IP address and service related
protocol/destination socket number are mapped to a private IP address
and protocol/destination socket number. This functionality allows
access from the Internet to only allowed server/services. If two
services, such as HTTP servers in different machines, are located on
the same LAN segment, they must have different socket numbers so
that the NAPT can map the address correctly. Only one server on each
socket number can be used.
6.5 IP address management
IP addresses can be used in M11 in two different ways:
D
WAN interface belongs to one logical IP subnet and the Ethernet
interface belongs to another logical IP subnet. This is how a
normal router operates.
D
WAN port has only one public IP address. The Ethernet interface
uses private IP addressing. Network Address Port Translation
(NAPT) is used to map the private IP addresses to and from a
single public IP address. The operation is analogous to existing
dial-up implementation, which consumes only a single IP address
and is the most efficient way to use IP addresses.
The IP address of the WAN interface can be set statically or
dynamically. Dynamic allocation of the IP address using IPCP (IP
control protocol) is possible when PPP over ATM AAL5 is used on an
ADSL WAN link. This operation is preferred when NAPT is used. For
bridged WAN encapsulation, the DHCP client can be used to retrieve
the IP configuration to the WAN port.
The IP address of the Ethernet interface and the subnet must be set
statically. However, the built-in DHCP server functionality can be
used to allocate an IP address, subnet mask, default gateway and DNS
address to host.