Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Single Public IP, many PC's and a WEB/FTP server

I have NAT running on my 1605R perfectly with my single public IP. Now I want to put a webserver behind the NAT.

Found a tech article:

Question is this:

How come the PC's cruising the web don't get diverted to the WEB server instead? PC1 might request a website and the reply should not go to the web server, but back to the PC. How is this accomplished. My mind tells me that there might be a problem with the port 80 replies.


Re: Single Public IP, many PC's and a WEB/FTP server

Your static NAT entry perform ing the port translation only comes into picture when an external devices wants to establish a connection to the public ip on port 80. It will not affect your other client connections as these will create their own NAT translations depending on your configuration. Another thing to note is that www replies to your internal clients will have a source port of 80 and the destination port will be 1024 or higher as chosen by the client when initiating the web connection.

New Member

Re: Single Public IP, many PC's and a WEB/FTP server

AHH, forgot about the Ephemeral port.

That clears it up in my head. Thanks.