5. Configuring the FrameSaver SLV Router

Network Address Translation

Network Address Translation (NAT) is used when a private network’s internal IP addresses cannot be used outside the private network. IP addresses may be restricted for privacy reasons, or they may not be valid public IP addresses.

he router provides NAT as described in RFC 1631, The IP Network Address ranslator (NAT). NAT allows hosts in a private (local) network to transparently

access the external (public or global) network by using a block of public addresses. Static mapping enables access to selected local hosts from the outside using these external IP addresses.

raditional NAT and Network Address Port Translation (NAPT) are supported. When both NAT and NAPT are enabled, one-to-one NAT mapping is performed by translating a range of assigned public IP addresses to a similar-sized pool of private addresses, followed by many-to-one NAPT bindings. Up to 254 IP addresses can be allocated for NAT usage.

IP Options Processing

he NAT and NAPT functions handle and process the IP datagrams with options set as described below. No command is available to set IP options.

he router does not process (and drops) any IP datagrams with the following IP options:

Loose source and record route (type 131)

Strict source and record route (type 133)

Security (type 130)

Stream ID (type 136)

he router does process IP datagrams with the following IP options, but does not provide its IP address or timestamp information in the response message:

Record route (type 7)

Timestamp (type 68)

Applications Supported by NAT

he router supports the following applications and protocols:

FTP

HTTP

Ping

RealPlayer

TTelnet

TFTP

9128-A2-GB20-80

September 2002

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Paradyne CSU, DSU, 9126-II, 9128-II Network Address Translation, IP Options Processing, Applications Supported by NAT