Crestron NAT, Reference Manual

2-Series Feature 

Crestron 

NAT

Portmap Page 

The PORTMAP page, shown below, permits public access from the external network 
onto the internal network. The IP address of the internal network is protected by 
reassignment of port numbers via NAT. Port numbers are used to route the packets to 
the correct process, or program running on the network-aware device. For example, a 
process such as a telnet session receives a temporary port number when the session 
starts; data is sent using that port number, and the port number goes out of use when 
the session ends. Other port numbers, called "well-known" port numbers, are 
permanently assigned; for example, e-mail data under SMTP goes to port number 25. 
Other well-known ports are listed at the end of this section.  

NOTE:

  This phase of NAT allows up to 16 port assignments. The value of each 

port number can range from 0 to 65535. 

PORTMAP Page 

NOTE:

  The three items entered on the page above corresponds to the internal 

network, which includes a CP2E and two Isys touchpanels as shown in the example 
on page 3.  

A process performed by a network-aware device on the internal network can be 
initiated from the external network. The NAT protects the anonymity of the internal 
network by remapping its known port assignments to ones that it publicizes. Each 
publicly accessible process must have an arbitrary external port number assigned to 
its known internal port number.  

For example, suppose there was a need to remotely upload a project to the Crestron 
touchpanel that resides on the internal LAN at IP address 192.168.16.3, as shown on 
the PORTMAP page above. Configure the following values.  

External Port 

The external port field requires an arbitrary number assignment for the known 
internal network process. The user on the external network initiates the process by 
entering the IP address (of the 2-Series control system with C2ENET-2 card 

10  

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  Network Address Translator: NAT 

Reference Guide – DOC. 6001