Copyright: Microsoft Backoffice Resource Kit, 2nd Edition: Exchange Tools © Microsoft Corporation 1998


ASN1 Decoder Tool

The ASN1 Decoder tool enables you to decode and interpret X.409 Abstract Syntax Notation 1 (ASN.1) data. The ASN.1 language is a language for describing structured information. In Microsoft Exchange, the message transfer agent (MTA) transmits P1 envelope data and sometimes P2 content data in ASN.1 format. ASN1 Decoder can be used to decode or interpret ASN.1 data, similar to the way in which the MTA would decode and interpret the data. The ASN1 Decoder tool supports P1, P2, and P772 data.

See Also

Installing ASN1 Decoder

Using ASN1 Decoder

Troubleshooting ASN1 Decoder


 Installing ASN1 Decoder

You can install this tool when you run the Microsoft BackOffice Resource Kit, Second Edition Setup program, or you can use the following procedure:

To install ASN1 Decoder

From the Exchange\<operating system\platform>\Admin\Aspirin directory on the Microsoft BackOffice Resource Kit, Second Edition  compact disc, copy Aspirin.exe to your computer.


 Using ASN1 Decoder

To run ASN1 Decoder

1	From the Start menu, choose Run, and then choose Browse to search for the folder or subdirectory where you copied the file.

2	Select the Aspirin folder, and then select Aspirin.exe.

To open a hexadecimal or binary-format ASN.1 file

1	From the File menu, choose Open.

2	Select Hex if the file contains ASN.1 data encoded as hexadecimal ASCII. Select Binary if the file contains ASN.1 data encoded as raw binary.

To produce ASN.1 data files from a Microsoft Exchange Server MTA log file

The Microsoft Exchange MTA logs messages and other information in the Exchsrvr\Mtadata directory as BF*.log files. These files contain, among other pieces of data, ASN.1 hexadecimal dumps of messages passing through the MTA. These ASN.1 blocks can be viewed by using ASN1 Decoder if they are parsed out of a BF*.log file. To view these ASN.1 blocks, using the following procedures:

1	From the File menu, choose Parse MTA Log.

2	Select a log file, such as Bfo.log, and then choose OK.

To view ASN.1 blocks

1	From the File menu, choose Parse MTA Log.

2	Select a log file, such as Bfo.log, and then choose OK.

After you follow these steps, ASN1 Decoder produces one hexadecimal file in the same directory as the log file for each block in the log file. Some, but not all blocks, are ASN.1 data. You can view the ASN.1 hexadecimal files by following the procedure outlined earlier.


Troubleshooting ASN1 Decoder

If you have problems during ASN.1 decoding, a message should appear describing the problem. If applicable, you are prompted to choose whether you want the decoder to attempt to continue. Continuing does not guarantee that the decoding will be successful.

If a decoder error is produced, verify that:

You have access permissions on the ASN.1 data file

The selected file is actually ASN.1 data

You chose the correct data format (hexadecimal or binary). If one format didn’t work, try the other.

If you have problems parsing an MTA BF*.log file, verify that:

You have permissions to create files in the BF*.log’s directory.

You have disk space available to create additional files.

The log file is not obviously corrupted.

The log file is not empty.

Interpreting Error Messages and Reporting Bugs

Note that not all references obtained from the BF*.log file are ASN.1 blocks. If they are not ASN.1 blocks, ASN1 Decoder generates the following error message:

ERROR: HRESULT=0xe0010004; Cannot identify beginning type.

Decoding stopped at offset 0.

If the offset number shown in the error message is 0, the reference in the BF*.log was not an ASN.1 block. If the offset number is not 0, part of the ASN.1 block was parsable, but problems were encountered during the parsing process. Offsets past offset 0 indicate potential interoperability problems and may warrant reporting to rkinput@microsoft.com.

The warnings described earlier indicate places where the ASN.1 interpreter could not interpret data. The warnings also may indicate potential interoperability problems with other MTAs. The following error should be reported to rkinput@microsoft.com.

WARNING: Uknown Type encountered at offset 465. Basic Encoding Rules
will be used for this type and its children.

When reporting bugs or making requests (such as feature requests), include the following information:

A detailed description of the problem or request.

Aspirin.exe version number.

Microsoft Exchange MTA version number.

Foreign MTA (if appropriate) number, and vendor and version number.

The .hex or .bin ASN.1 file or the BF*.log with the problem.