The following is a form that gets posted to your NVG510 router. Do NOT use it if you do not have such a router and in any event, use at your own risk.

Enable Telnet on your NVG510

1. Get a session identifier

1.1 Go to a page while logged in

Go to http://192.168.1.254/cgi-bin/etherlan.ha. If you are not logged in your router yet, enter your log in information.

NOTE

The same hack works using other pages such as the wanethconfig.ha page and any other values could be changed. This form allows you to modify the mgmt.shell.telnet-port variable, but there are a few hundred values to change in your router!

1.2 Retrieve the nonce value

Once the page loaded, it contains the session identifier in a value named "nonce". It is part of the HTML code, so use your right mouse button to open the HTML source code of that page (if you're on a Mac, good luck) and then do a find (Ctrl-F) on the word nonce. You should see something that looks like the following: 

<input type="hidden" name="nonce"
      value="815a0aaa0000176012db85d7d7cac9b31e749a44b6551d02" />

Copy the nonce parameter value, the long string of letters and digits, in the nonce field below. In this example, you'd copy:

815a0aaa0000176012db85d7d7cac9b31e749a44b6551d02

But do not copy this very value, chances for your nonce to be the same are really slim.

2. Enable/Disable Telnet

2.1 Select whether you want to enable or disable telnet

Select whether you want to enable (Telnet Port 23) or disable (Telnet Disable) telnet access to your NVG510.

Telnet Port:

2.2 Copy the nonce session identifier

The nonce value is your current session identifier. It is required for forms to be accepted by your NVG510. It will work only if you are connected via 192.168.1.254 and logged in. Step 1.2 shows you how to get the value.

Nonce value:

2.3 Save Telnet Port

Now you are ready to save the new information. Note that you can use this mechanism to restore the telnet port to zero by selecting the Disable Telnet option.

When you click the Save button, you are sent back to your router. There the router should reply saying that the changes were saved successfully with the message: Changes Saved

References: