Commands Reference, Volume 4

named4 Daemon

Purpose

Provides the server function for the Domain Name Protocol.

Syntax

/usr/sbin/named4 [ -d DebugLevel ] [ -p PortNumber ] [ -b BootFile ]

Description

The /usr/sbin/named4 daemon is the server for the Domain Name Protocol (DOMAIN). The named4 daemon runs on name-server hosts and controls the domain-name resolution function.

This operating system provides two name server daemons, the named4 daemon and the named8 daemon. While both provide the same service of domain-name resolution, the named8 daemon supports the more robust configuration file named.conf. The named4 daemon is provided and enabled by default for backwards compatibility as it is configured with the more simplistic named.boot file.

Selection of which name server daemon to use is controlled by the /usr/sbin/named and /usr/sbin/named-xfer symbolic links. By default, these are links to the named4 and named4-xfer executables, but can be changed to reference the named8 and named8-xfer executables. Note that it is required that both symbolic links are changed in tandem, as the version 4 name server is not compatible with the version 8 zone transfer, and visa-versa.

Note:The named4 daemon can be controlled using the System Resource Controller (SRC) or the System Management Interface Tool (SMIT). Use the rc.tcpip file to start the daemon with each system startup.

Thenamed4daemon listens for name-server requests generated by resolver routines running on foreign hosts. The daemon listens to the socket defined in the /etc/services file; the entry in the /etc/services file begins with domain . However, this socket assignment can be overridden using the -pflag on the command line.

Note:The /etc/resolv.conf file tells the local kernel and resolver routines to use the DOMAIN protocol. The /etc/resolv.conf file must exist and contain either the local host's address or the loopback address (127.0.0.1), or be empty to use the named4 daemon on the DOMAIN name server host. If the /etc/resolv.conf file does not exist, the local kernel and resolver routines use the /etc/hosts database. When this occurs, the named4daemon does not function properly.

Manipulating the named4 Daemon with the System Resource Controller

The named4 daemon is a subsystem controlled by the System Resource Controller (SRC). The named4 daemon is a member of the tcpip system group. This daemon is disabled by default and can be manipulated by the following SRC commands:

startsrc	Starts a subsystem, group of subsystems, or a subserver.
stopsrc	Stops a subsystem, group of subsystems, or a subserver.
refresh	Causes the named4daemon to reread the /etc./named.boot file. Depending on the contents of the file, the refresh command may or may not reload the database.
traceson	Enables tracing of a subsystem, group of subsystems, or a subserver.
tracesoff	Disables tracing of a subsystem, group of subsystems, or a subserver.
lssrc	Gets the status of a subsystem, group of subsystems, or a subserver.

Flags

-bBootFile	Specifies an alternate boot file.
-dDebugLevel	Provides a debugging option. The -d flag causes the named4daemon to write debugging information to a file named /var/tmp/named.run. The DebugLevel variable determines the level of messages printed, with valid levels from 1 to 11, where level 11 supplies the most information.
-pPortNumber	Reassigns the Internet socket where thenamed4daemon listens for DOMAIN requests. If this variable is not specified, thenamed4daemon listens to the socket defined in the /etc/services file; the entry in the /etc/services file begins with `domain` .

Signals

The following signals have the specified effect when sent to the named4 daemon process using the kill command:

SIGHUP	Thenamed4 daemon rereads the /etc/named.bootfile. Depending on the contents of the file, the SIGHUP signal may or may not reload the database.
SIGINT	The named4 daemon dumps the current database to a file named/var/tmp/named_dump.db. In the dump file, names with the label name error indicate negative cache entries. This happens when a server responds that the specified domain name does not exist. Names labeled as data error also indicate negative cache entries. This happens when a server responds that there are no records of the specified type for the (valid) domain name.
SIGUSR1	Thenamed4 daemon turns on debugging; each subsequent SIGUSR1 signal increments the debugging level. The debugging information is written to the /var/tmp/named.run file.
SIGUSR2	Thenamed4 daemon turns off debugging.
SIGABRT/SIGIOT	Thenamed4 daemon dumps the current statistics to the /var/tmp/named.stat file.

Examples

To start the named4 daemon normally, enter the following:
```
startsrc -s named
```
This command starts the daemon. You can use this command in the rc.tcpip file or on the command line. The -s flag specifies that the subsystem that follows is to be started. The process ID of the named4 daemon is stored in the /etc/named.pid file upon startup.
To stop the named4 daemon normally, enter:
```
stopsrc -s named
```
This command stops the daemon. The -s flag specifies that the subsystem that follows is to be stopped.
To get short status from the named4 daemon, enter:
```
lssrc -s named
```
This command returns the name of the daemon, the process ID of the daemon, and the state of the daemon (active or inactive).
To enable debugging for the named4 daemon, enter:
```
traceson -s named
```
OR
```
kill -30 `cat /etc/named.pid`
```
Thenamed4 daemon turns on debugging in response to either of these commands; each subsequent command increments the debugging level. The debugging information is written to the /var/tmp/named.run file.
To turn off debugging for the named4 daemon, enter:
```
tracesoff
```
OR
```
kill -35 `cat /etc/named.pid`
```
Either of these commands immediately turns off all debugging.
To start the named4 daemon at the highest debugging level using the startsrc command, enter the following:
```
startsrc -s named -a -d 11
```
This command writes debugging messages to the /var/tmp/named.run file.

Files

/usr/sbin/named4	Contains the named daemon.
/etc/resolv.conf	Specifies the use of domain name services.
/etc/rc.tcpip	Initializes daemons at each system restart.
/etc/named.pid	Stores process IDs.
/etc/services	Defines socket service assignments.
/usr/samples/tcpip/named.boot	Contains the sample named.boot file with directions for its use.
/usr/samples/tcpip/named.data	Contains the sample DOMAIN data file with directions for its use.
/usr/samples/tcpip/hosts.awk	Contains the sample awk script for converting an /etc/hosts file to an /etc/named.data file. This file also contains directions for its use.
/usr/samples/tcpip/addrs.awk	Contains the sample awk script for converting an /etc/hosts file to an /etc/named.rev file. This file also contains directions for its use.
/usr/samples/tcpip/named.dynamic	Contains a dynamic database setup.

Related Information

The nslookup command, traceroute command, kill command.

The named8 daemon.

The named.conf file format, DOMAIN Cache file format, DOMAIN Data file format, DOMAIN Reverse Data file format, DOMAIN Local Data file format, resolv.conf file format.

TCP/IP Name Resolution and TCP/IP Daemons in AIX 5L Version 5.2 System Management Guide: Communications and Networks.

Configuring Name Servers and Planning for DOMAIN Name Resolution in AIX 5L Version 5.2 System Management Guide: Communications and Networks.