All command line options for DNS server are optional.
If the DNS server is loaded without any options, default values for all of the options, wherever applicable, are used.
To start a DNS server, enter the following command at the server console prompt:
load named
Command line options can be specified in three different scenarios:
Load: This is the first time the DNS server is loaded.
Stop state: The server can be stopped by using the management utilities. The NLM remains loaded, but it supports only a limited set of services.
Reload: The load named command can be issued repeatedly after a new load. After a new load, the load named command is used to issue command line options.
The command line options are listed in the table below.
Table 4-2 Named Command Line Options
Some command line options can be specified only at load time. These options control the behavior that can be set only once for a particular running session (load, followed by multiple reloads, and finally the unload) of the DNS server. If you specify an invalid value for such an option at the load time, the server exits, because after the server is up and running, these options cannot be used again. These options are ignored at reload time or when the server is in the stop state. However, the server comes up if the options are also available in reload because the user can set the desired behavior later.
Syntax: named [-dc categories] [-dl debuglevel] [-ft on|off] [-jsize] [-info] [-mstats] [-n no_of_cpus] [-p port_no] [-pa] [-qstats] [-r on|off] [-rp character] [-s] [-v volumename] [-zi zonename] [-?]
Usage Syntax: –?
Cluster Enabling Syntax: –v volume_name
By default, the DNS server uses the sys: volume to store backup zone files, journal files, and other files.
This option enables clustering, by providing a volume other than sys:. The volume name specified as the argument should exist and be mounted on the NetWare server.
Example: Load named –v new_volume
If new_volume exists and is mounted on the NetWare server, the DNS server stores all files to this volume. For example, the log file named.run is created at new_volume:named.run and the zone data files are stored at new_volume:etc\dns\*.db.
Debugging Categories Syantax: –dc categories
Logging is enabled for the categories specified with this option. For all other categories, no information is logged. When you specify the value all, logging is enabled for all the categories. By default, logging is enabled for all categories with the current debugging level as specified by the -dl option.
Table 4-3 Command Line Description
Debugging Level Syntax: –dl level
This option sets the level of information to be logged. If –dl is given 0 as the input, the debug messages of type information (level -1)/notice/warning/error/critical (level –5) are logged for all categories. For a positive level, for example n, all debug messages up to level n are logged.
It is recommended that the debug level should be less (not more than +2) while running named in a live environment because this impacts the server performance.
The default value for logging is notice [-2]. Only critical and error messages are displayed on the named screen. All other messages are logged in volume_name:\named.run file, where volume_name is the volume that is specified with -v option. The default volume is sys:.
DNS Port Syntax: –p port_number
The port specified in this option is used by the DNS server to listen for queries. The values for this option can be in the range 1-65535. The default port number is 53. This option is ignored if it is specified at the reload or in the stop state.
Dynamic Reconfiguration Syntax: –r on|off
If dynamic reconfiguration is enabled, the DNS server periodically checks the configuration data for the server and zones. As part of this activity, it will automatically detects added, deleted, and modified zones. This option has no effect on periodically checking the directory for changes in the zone data. Even if the dynamic reconfiguration is set to off, periodic detection of zone data will occurs. The default period for dynamic reconfiguration is 15 minutes.
Fault Tolerance Syntax: –ft on|off
When this option is set to on, the DNS server can start by using the backup files if eDirectory is inaccessible. If off is specified for a new load, the DNS server will not service the zones for which eDirectory is not available.
Force Zone-In Syntax: –zi zone_name
Zone transfers can be initiated by using this option for secondary zones. The domain name of the zone should be specified as the argument to the command line option. Force zone-in is only initiated if the zone is secondary and the DNS server is a designated secondary server for the zone. This option is ignored in the Stop mode or fresh load.
NOTE:Force Zone-In is not supported on Linux.
Number of CPUs Syntax: –n number_of_cpus
Specifies the number of CPUs available. The default value is 1 and the maximum value that can be specified is 32.
Replace Characters Syntax: –rp characters
A set of characters that are not allowed in the hostnames. The current list is ~!@#$%^&*+=?’`:;,"<>\/()[]{}|. This option can be used to add characters to this list. If these characters are found in the hostnames, the DNS server replaces these characters with a dash (-) before storing them in eDirectory. This option is included for backward compatibility and only allows adding one more character to the existing list.
Memory Statistics Syntax: –mstats
This option saves the memory usage information for the DNS server to a file named.mem in the volume_name:sys\etc\ directory. This information is very important to determine the load on the DNS server.
Named.mem contains information for each memory pool. The following information is saved to the named.mem file.
Name of the memory pool
Size of each item in the pool
Maximum number of items allowed
Number of items currently allocated
Number of items in the reserved list
Number of items allowed in the free list
Number of items to fetch in each fill
Number of requests to this pool
Pool locked YES (Y)/NO (N)
Query Statistics Syntax: -qstats
This option saves the DNS server query statistics information to volume_name:etc\dns\named.sta. This information is similar to the memory statistics information and helps to determine the load on the DNS server. Using this information, the DNS server can be configured for better performance. The following information is saved to the named.sta file:
Number of queries answered successfully
Number of queries referred to other servers
Number of queries that were replied with non-existent RRset error code
Number of queries that were replied with non-existent domain error code
Number of queries that caused recursion
Number of queries that failed
Purge All Cache Syntax: –pa
This option causes the server to purge all cache maintained in it.
Screen Logging Syntax: –s
Displays the log information on the named screen along with the named.run file.
Zone Information Syntax: –info info_file
This option provides information about the zones that are currently loaded in the server.
The syntax of the information is: Zone ZONE_NAME of type MASTER/SLAVE has N nodes and SOA sr no, is SOA_SR_NO
This information is saved to the file, if specified in the command line. Otherwise, it is displayed on the console screen.
Restricting Journal Log File Size Syntax: - jsize Size in Kilo Bytes
The journal log file is used by the DNS servers for incremental zone transfers, and the size of the file increases based on the changes made. By default, there is no restriction on the size of a journal log file. This option can be used to specify the size (in KB) of the journal log file.
During dynamic reconfiguration, the journal log file is deleted if its size exceeds the specified amount. Because the journal log files are deleted only on the lapse of the dynamic reconfiguration interval (minimum 10 minutes and maximum of 1 day), adequate size must be allocated for the journal log files.
Example. Named -jsize 5000.
During dynamic reconfiguration, this command deletes all the journal log files exceeding 5000 KB (or 5 MB).