Debugging and Decoding

The Mib Browser application provides facility to view the debug output of the SNMP operations. The Debug window is used to show the PDU that is sent from the manager and the response PDU that is got from the agent.

Invoking the Debug Window

Click the Debug icon in the toolbar or select View-->Debug from the menu bar. You can also use the shortcut key combination Alt + D. This would invoke the Debug window.
As long as this Debug window is opened, debugging is turned on and the debugging output is displayed. When this window is closed, debugging is turned off.

The image below depicts a Debug window.

The three icons in the debug window provide the following function.

Save MibBrowser Debug Results - Saves the debug information to a file.

Print MibBrowser Debug Results - Prints the debug information to a file.

Snmp Decoder - Switches over to the Decoder window.

The Clear button clears the debug information and the Close button closes the Debug window.

Invoking the Decoder Window

To switch over from the Debug window to the Decoder window, click the Decoder icon. The Decoder icon toggles to a Debug button.
The three icons in the Debug window provide the following functions.

Save MibBrowser Decoder Results - Saves the debug information to a file.

Print MibBrowser Decoder Results - Prints the debug information to a file.

Debug - Switches over to the Debug window.

Note: The Save and Print options are available only when the MibBrowser is invoked as an application and not as an applet because of security restrictions.

Performing the Decoding Operation

The Snmp Decoder is used to decode the SNMP debug messages. The figure below depicts the SNMP Decoder.

To decode the debug information, select the PDU in the debug window and click the Snmp Decoder icon. This will switch over to the decoder window. Now, the selected debug information is available in the "Hex PDU" text area. Click the Decode button to decode the information. The decoded message is displayed in the bottom panel of the Decoder window.

If the debug message was stored in a file, the decoding can be done by loading the file. This can be done by clicking the Browse button in the Debug frame. You can also enter the URL in the File URL text field and press the 'Enter' key. However, saving and loading of debug information files is done only in applications and not in applets.

Warning: You can select the entire PDU debug message displayed in the Debug window with all the strings and click the Decoder button to display the selected information in the Hex PDU text area. You can also save the debug message in the Debug window and load it in the Decoder window. The decoder will decode all the PDU dumps leaving the informative strings. The limitation in this is that the two continuous PDUs should have a string delimiter as a new line in between them.

A sample PDU is depicted below.

3 0 26 02 01 00 04 06 70 75 62 6c 69 63 a0 19 02 01 04 02 01
00 02 01 00 30 0e 30 0c 06 08 2b 06 01 02 01 01 05 00 05 00

Packet from: 192.168.1.215 : 161
DATA:
30 2e 02 01 00 04 06 70 75 62 6c 69 63 a2 21 02 01 04 02 01
00 02 01 00 30 16 30 14 06 08 2b 06 01 02 01 01 05 00 04 08
4b 41 4e 4e 41 4e 4b 41

The highlighted strings will be the delimiter between the two continuous PDU dumps. In case there is no string delimiter as above, only the first PDU is decoded. You can also save the decoded information using the Save button. The Save button in the Debug view saves the debug information.