Tracing L2TP Events for Troubleshooting

By default, the name of the file that records trace output for L2TP is jl2tpd. You can specify a different name with the file option.

To configure the filename for L2TP tracing operations:

• Specify the name of the file used for the trace output.

You can optionally specify the number of compressed, archived trace log files to be from 2 through 1000. You can also configure the maximum file size to be from 10 KB through 1 gigabyte (GB); the default size is 128 kilobytes (KB).

The archived files are differentiated by a suffix in the format .number.gz. The newest archived file is .0.gz and the oldest archived file is .(maximum number)-1.gz. When the current trace log file reaches the maximum size, it is compressed and renamed, and any existing archived files are renamed. This process repeats until the maximum number of archived files is reached, at which point the oldest file is overwritten.

For example, you can set the maximum file size to 2 MB, and the maximum number of files to 20. When the file that receives the output of the tracing operation, filename, reaches 2 MB, filename is compressed and renamed filename.0.gz, and a new file called filename is created. When the new filename reaches 2 MB, filename.0.gz is renamed filename.1.gz and filename is compressed and renamed filename.0.gz. This process repeats until there are 20 trace files. Then the oldest file, filename.19.gz, is simply overwritten when the next oldest file, filename.18.gz is compressed and renamed to filename.19.gz.

To configure the number and size of trace files:

• Specify the name, number, and size of the file used for the trace output.

By default, only the user who configures the tracing operation can access the log files. You can enable all users to read the log file and you can explicitly set the default behavior of the log file.

To specify that all users can read the log file:

• Configure the log file to be world-readable.

To explicitly set the default behavior, only the user who configured tracing can read the log file:

• Configure the log file to be no-world-readable.

By default, the trace operation output includes all lines relevant to the logged events.

You can refine the output by including regular expressions to be matched.

To configure regular expressions to be matched:

• Configure the regular expression.

For subscriber usernames that have the expected form of user@domain, you can filter on the user, the domain, or both. You can use an asterisk (*) as a wildcard to substitute for characters at the beginning or end of either term or both terms to match a greater number of subscribers.

When you enable filtering by username, traces that have insufficient information to determine the username are automatically excluded.

To configure subscriber filtering:

• Specify the filter.

  Note:

  This syntax is different than the syntax used to filter subscribers on M Series routers.

Consider the following examples of using the wildcard for filtering:

• Filter results for the specific subscriber with the username, tom@example.com.

• Filter results for all subscribers whose username begins with tom.

• Filter results for all subscribers whose username ends with tom.

• Filter results for subscribers with the username tom at all domains beginning with ex.

• Filter results for all subscribers at all domains that end with ample.com.

• Filter results for all subscribers whose username begins with tom at domains that end with example.com.

By default, only important events are logged. You can specify which events and operations are logged by specifying one or more tracing flags.

To configure the flags for the events to be logged:

• Configure the flags.

The messages associated with a logged event are categorized according to severity level. You can use the severity level to determine which messages are logged for the event type. A low severity level is less restrictive—filters out fewer messages—than a higher level. When you configure a severity level, all messages at that level and all higher (more restrictive) levels are logged.

The following list presents severity levels in order from lowest (least restrictive) to highest (most restrictive). This order also represents the significance of the messages; for example, error messages are of greater concern than info messages.

• verbose

• info

• notice

• warning

• error

The severity level that you configure depends on the issue that you are trying to resolve. In some cases you might be interested in seeing all messages relevant to the logged event, so you specify all. You can also specify verbose with the same result, because verbose is the lowest (least restrictive) severity level; it has nothing to do with the terseness or verbosity of the messages. Either choice generates a large amount of output. You can specify a more restrictive severity level, such as notice or info to filter the messages. By default, the trace operation output includes only messages with a severity level of error.

To configure the type of messages to be logged:

• Configure the message severity level.