LINUX Name Service

The LINUX Name Service is used to provide DNS on the sipXecs server.

RedHat files of interest:

/etc/named.conf
/var/named/*.zone (on DNS master)
/var/named/data/*.zone (on DNS slave)

SUSE files of interest:

/etc/named.conf
/var/lib/named/*.zone (on DNS master)
/var/lib/named/data/*.zone (on DNS slave)

Commands of interest:

service named restart (used if named.conf or *.zone file updated)
rndc reload (used if *.zone file updated)

Generation of sipXecs DNS files

The initial installation of sipXecs creates the named.conf file and a host domain zone file. If the host domain name is different from the SIP domain name it will also generate a SIP domain zone file. However after installation only the host domain zone file (which is also the only zone file in a typical installation) will be updated by sipXecs server profile generation. The SIP domain zone file (if present) must be updated manually.

After the initial installation of sipXecs the generated named.conf file will contain a comment warning the installer that the host domain zone file may get overwritten. The named.conf file will also contain the DNS mode, for example:

// WARNING: Name server configuration is a sipX automatically generated file.
// Contents may be overwritten unless you change the mode to "Manual".
// Available modes:
// "Master" - Master name server (on primary server).
// "Slave" - Slave named server (on distributed server).
// "Caching" - Caching only name server.
// "Manual" - Blocks future automatic updates.
// DNS_MODE="Master"

The DNS_MODE line can be changed by the installer so that the host domain zone file no longer gets overwritten.

The sipXecs configuration options are described below:

Primary system SHOULD NOT be my DNS server (caching-only DNS server):
- Primary server
  - The named.conf file will have DNS_MODE "Caching".
  - No named/*.zone file will be generated.
- Distributed server
  - The named.conf file will have DNS_MODE "Slave", DNS is slaved to the primary server.
    (Unchanged by this update but not sure if this is the best choice, perhaps it should use "Caching" also).

Primary system SHOULD be my DNS server (master DNS server):
- Primary server
  - The named.conf file will have DNS_MODE "Master".
  - The *.zone file will be automatically regenerated (can be forced using Send Profile to the primary server).
- Distributed server
  - The named.conf file will have DNS_MODE "Slave", DNS is slaved to the primary server.
  - The *.zone file will be automatically copied from the primary server whenever a file update is detected.
    (zone file is copied into the named/data directory)
    (detects changes in the serial number in the *.zone file)

If the installer changes the DNS_MODE in named.conf from "Master" to "Manual" then the *.zone file will no longer be automatically generated on the primary server. The installer can then add additional DNS names to the *.zone file and they won't get overwritten by the system. The installer will then be responsible for changing the serial number in the zone file so that it gets automatically copied to the slave DNS servers.

GUI Configuration of DNS

Webmin provides a comprehensive DNS configuration system that eases DNS administration. This assumes you've changed the

// DNS_MODE="Master"

line in /etc/named.conf to

// DNS_MODE="Manual"

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