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PIX 501 firewall configuration: Network address translation

Systems integrators and VARs can use network address translation to give users inside the PIX firewall access to the Internet.

Now that we have IP address connectivity, we need to use Network Address Translation (NAT) to allow inside users to connect to the outside. We will use a type of NAT, called PAT or NAT Overload, so that all inside devices can share one public IP address (the outside IP address of the PIX firewall). To do this, enter these commands:


PIX1(config)# nat (inside) 1   
PIX1(config)# global (outside) 1 
Global will be Port Address Translated

With this, all inside users are able to connect to devices on the public network and share IP address However, clients don't yet have any rule allowing them to do this.

PIX firewall configuration

 Step 1: The basics
 Step 2: Guidelines
 Step 3: Configuration setup
 Step 4: PIX configuration
 Step 5: Network address translation
 Step 6: Firewall rules
 Step 7: Showing and saving configuration

David Davis
David Davis

About the author:
David Davis (CCIE #9369, CWNA, MCSE, CISSP, Linux+, CEH) has been in the IT industry for 15 years. Currently, he manages a group of systems/network administrators for a privately owned retail company and authors IT-related material in his spare time. He has written more than 50 articles, eight practice tests and three video courses and has co-authored one book. His Web site is

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