Logging Domain Name System server messages

Domain Name System (DNS) provides numerous logging options that can be adjusted when you are trying to find the source of a problem. Logging provides flexibility by offering various severity levels, message categories, and output files so that you can fine-tune logging to help you find problems.

BIND 8 offers several new logging options. You can specify what types of messages are logged, where each message type is sent, and what severity of each message type to log. In general, the default logging settings are suitable, but if you want to change them, it is recommended that you refer to other sources of BIND 8 documentation for information about logging.

Logging channels

The DNS server can log messages to different output channels. Channels specify where logging data is sent. You can select the following channel types:

• File channels

  Messages logged to file channels are sent to a file. The default file channels are as400_debug and as400_QPRINT. By default, debug messages are logged to the as400_debug channel, which is the NAMED.RUN file, but you can specify to send other message categories to this file as well. Message categories logged to as400_QPRINT are sent to a QPRINT spool file for user profile QTCP. You can create your own file channels in addition to the default channels provided.

• Syslog channels

  Messages logged to this channel are sent to the servers job log. The default syslog channel is as400_joblog. Logging messages routed to this channel are sent to the joblog of the DNS server instance.

• Null channels

  All messages logged to the null channel will be discarded. The default null channel is as400_null. You can route categories to the null channel if you do not want the messages to appear in any log file.

Message categories

Messages are grouped into categories. You can specify what message categories should be logged to each channel. There are many categories, including:

• config: Configuration file processing

• db: Database operations

• queries: Generates a short log message for every query the server receives

• lame-servers: Detection of bad delegations

• update: Dynamic updates

• xfer-in: Zone transfers the server is receiving

• xfer-out: Zone transfers the server is sending

Log files can become large and they should be deleted on a regular basis. All DNS server log file contents are cleared when the DNS server is stopped and started.

Message severity

Channels allow you to filter by message severity. For each channel, you can specify the severity level for which messages are logged. The following severity levels are available:

• Critical

• Error

• Warning

• Notice

• Info

• Debug (specify debug level 0-11)

• Dynamic (inherit the server startup debug level)

All messages of the severity you select and any levels above it in the list are logged. For example, if you select Warning, the channel logs Warning, Error, and Critical messages. If you select Debug level, you can specify a value from 0 to 11 for which you want debug messages to be logged.

Changing logging settings

To access logging options, follow these steps:

1. In iSeries™ Navigator, expand your system > Network > Servers > DNS.

2. In the right pane, right-click your DNS server and select Configuration.

3. In the DNS configuration window, right-click DNS server and select Properties.

4. In the Server Properties window, select the Channels tab to create new file channels or properties of a channel, such as the severity of messages logged to each channel.

5. In the Server Properties window, select the Logging tab to specify which message categories are logged to each channel.

Troubleshoot tip

The as400_joblog channel default severity level is set to Error. This setting is used to reduce the volume of informational and warning messages, which can otherwise degrade performance. If you are experiencing problems but the joblog is not indicating the source of the problem, you might need to change the severity level. Follow the procedure above to access the Channels page and change the severity level for the as400_joblog channel to Warning, Notice, or Info so you can view more logging data. After you have resolved the problem, reset the severity level to Error to reduce the number of messages in the joblog.

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