named - Internet domain name server
named [-4] [-6] [-c config-file] [-d debug-level] [-f] [-g] [-n #cpus] [-p port] [-s] [-t directory] [-u user] [-v] [-x cache-file] [-D]
named is a Domain Name System (DNS) server, part of the BIND 9 distribution from ISC. For more information on the DNS, see RFCs 1033, 1034, and 1035.
When invoked without arguments, named will read the default configuration file /etc/named.conf, read any initial data, and listen for queries.
In routine operation, signals should not be used to control the nameserver; rndc should be used instead.
SIGHUP Force a reload of the server.
The result of sending any other signals to the server is undefined.
The named configuration file is too complex to describe in detail here. A complete description is provided in the BIND 9 Administrator Reference Manual.
Red Hat SELinux BIND Security Profile:
By default, Red Hat ships BIND with the most secure SELinux policy that will not prevent normal BIND operation and will prevent exploitation of all known BIND security vulnerabilities . See the selinux(8) man page for information about SElinux.
It is not necessary to run named in a chroot environment if the Red Hat SELinux policy for named is enabled. When enabled, this policy is far more secure than a chroot environment.
With this extra security comes some restrictions: By default, the SELinux policy does not allow named to write any master zone database files. Only the root user may create files in the $ROOTDIR/var/named zone database file directory (the options { “directory” } option), where $ROOTDIR is set in /etc/sysconfig/named. The “named” group must be granted read privelege to these files in order for named to be enabled to read them. Any file created in the zone database file directory is automatically assigned the SELinux file context named_zone_t . By default, SELinux prevents any role from modifying named_zone_t files; this means that files in the zone database directory cannot be modified by dynamic DNS (DDNS) updates or zone transfers. The Red Hat BIND distribution and SELinux policy creates two directories where named is allowed to create and modify files: $ROOTDIR/var/named/slaves and $ROOTDIR/var/named/data. By placing files you want named to modify, such as slave or DDNS updateable zone files and database / statistics dump files in these directories, named will work normally and no further operator action is required. Files in these directories are automatically assigned the ‘named_cache_t’ file context, which SELinux allows named to write. You can enable the named_t domain to write and create named_zone_t files by use of the SELinux tunable boolean variable “named_write_master_zones", using the setsebool(8) command or the system-config-security GUI . If you do this, you must also set the ENABLE_ZONE_WRITE variable in /etc/sysconfig/named to 1 / yes to set the ownership of files in the $ROOTDIR/var/named directory to named:named in order for named to be allowed to write them.
Red Hat BIND named_sdb SDB support:
Red Hat ships the bind-sdb RPM that provides the /usr/sbin/named_sdb
program, which is named compiled with the Simplified Database Backend
modules that ISC provides in the “contrib/sdb” directory.
The SDB modules for LDAP, PostGreSQL and DirDB are compiled into
named_sdb.
To run named_sdb, set the ENABLE_SDB variable in /etc/sysconfig/named
to 1 or “yes", and then the “service named start” named initscript will
run named_sdb instead of named .
See the documentation for the various SDB modules in
/usr/share/doc/bind-sdb-*/ .
Red Hat system-config-bind:
Red Hat provides the system-config-bind GUI to configure named.conf and zone database files. Run the “system-config-bind” command and access the manual by selecting the Help menu.
/etc/named.conf
The default configuration file.
/var/run/named.pid
The default process-id file.
RFC 1033, RFC 1034, RFC 1035, rndc(8) , lwresd(8) , BIND 9 Administrator Reference Manual.
Internet Systems Consortium