R0106-HP MSR Router Series Layer 3 - IP Services Command Reference(V7)

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Usage guidelines
You can configure the NAT Server feature to allow internal servers (such as Web, FTP, Telnet, POP3, and
DNS servers) in the internal network or an MPLS VPN instance to provide services for external users.
NAT Server is usually configured on the interface that connects the external network on a NAT device. By
using the global-address and global-port arguments, external users can access the internal server at
local-address and local-port. The following table describes the address-port mappings between an
external network and an internal network for NAT Server.
Table 43 Address-port mappings for NAT Server
External network
Internal network
An external address An internal address.
An external address and an external port number An internal address and an internal port number.
An external address and N consecutive external port
numbers
An internal address and an internal port number.
N consecutive internal addresses and an internal port
number.
An internal address and N consecutive internal port
numbers.
N consecutive external addresses
An internal address.
N consecutive internal addresses.
N consecutive external addresses and an external
port number
An internal address and an internal port number.
N consecutive external addresses and an internal port
number.
An internal address and N consecutive internal port
numbers.
An external address and an external port number
An internal server group.
An external address and N consecutive external port
numbers
N consecutive external addresses and an external
port number
The number of the nat server commands that can be configured on an interface varies by device model.
The number of internal servers that each command can define equals the difference between
global-port2 and global-port1.
When the protocol type is not udp (protocol number 17) or tcp (protocol number 6), you can configure
only one-to-one IP address mapping.
If one of the two arguments global-port and local-port is set to 0, the other must also be 0 or remain
undefined.
The mapping between the protocol type, external address, and external port number must be unique for
an internal server on an interface.
If the IP address of an interface used by Easy IP changes and conflicts with the IP address of an internal
server not using Easy IP, the Easy IP configuration becomes invalid. If the conflicted address is modified
to an unconflicted address or the internal server configuration without Easy IP is removed, the Easy IP
configuration takes effect.