This topic helps you to understand the files Domain Name System (DNS) uses and review guidelines for backing up and maintaining them.
You can use i5/OS™ DNS to create and manage DNS server instances on your iSeries™. The configuration files for DNS are managed by iSeries Navigator. You should not manually edit the files. Always use iSeries Navigator to create, change, or delete DNS configuration files. DNS configuration files are stored in the integrated file system paths listed below.
Note: The file structure below applies
to DNS running on BIND 8. If you are using DNS based on BIND 4.9.3, see Backing up DNS configuration files and maintaining log files in
the V4R5 DNS Information Center topic.
In the following table, files
are listed in the hierarchy of paths shown. Files with a save icon 
should be backed
up to protect data. Files with a delete icon 
should be deleted on a regular basis.
| Name | Icon | Description |
|---|---|---|
| QIBM/UserData/OS400/DNS/ | Starting point directory for DNS. | |
| ATTRIBUTES | |
DNS uses this file to determine which BIND version you are using. |
| QIBM/UserData/OS400/DNS/ <instance-n>/ | Starting point directory for a DNS instance. | |
| ATTRIBUTES | |
Configuration attributes used by iSeries DNS. |
| NAMED.CONF | |
This file contains configuration data. Used to tell the server what specific zones it is managing, where the zone files are, which zones can be dynamically updated, where its forwarding servers are, and other option settings. |
| BOOT.AS400BIND4 | |
BIND 4.9.3 server configuration and policies file that is converted to the BIND 8 NAMED.CONF file for this instance. This file is created if you migrate a BIND 4.9.3 server to BIND 8. It serves as a backup for migration, and can be deleted when the BIND 8 server is working properly. |
| NAMED.CA | |
List of root servers for this server instance. |
| NAMED_DUMP.DB | |
Server data dump created for the active server database. |
| NAMED.STATS | |
Server statistics. |
| NAMED.PID | Holds Process ID of running server. This file is created each time the DNS server is started. It is used for the Database, Statistics, and Update server functions. Do not delete or edit this file. | |
| QUERYLOG | |
The DNS server log of queries received. The file is created when the DNS server log is active. When active, this file becomes large and it should be deleted on a regular basis. |
| <zone-name-a>.DB | |
Zone file for a particular domain to be served by this server. Contains all of the resource records for this zone. |
| <zone-name-b>.DB | |
Zone file for a particular domain to be served by this server. Contains all of the resource records for this zone. Each zone has a separate .DB file. |
| *.ixfr.* | |
Incremental zone transfer (IXFR) files. These files are used by secondary servers to load only changed data since the last zone transfer. As updates are made, the number of IXFR files will grow. You should periodically delete the older IXFR files. Leaving files that were created within a day or two will allow most secondaries to still load IXFRs. If you delete all of the files, the secondary will request a full transfer (AXFR). |
| TMP | Directory used by server instance for creating temporary work files. | |
| QIBM/UserData/OS400/DNS/TMP | Temp directory used by QTOBH2N program to create intermediate files dumped from the host table for later import using iSeries Navigator. | |
| QIBM/UserData/OS400/DNS/_DYN/ | Directory that holds files required for dynamic updates. | |
| <key_id-name-x>._KID | |
File containing a BIND 8 key statement for the key_id named <key_id-name-x>. |
| <key_id-name-x>._DUK. <zone-name-a> | |
Dynamic update key required to initiate a dynamic update request to <zone-name-a> using the <key_id-name-x> key. |
| <key_id-name-y>._KID | |
File containing a BIND 8 key statement for the key_id named <key_id-name-y>. |
| <key_id-name-y>._DUK. <zone-name-a> | |
Dynamic update key required to initiate a dynamic update request to <zone-name-a> using the <key_id-name-y> key. |
| <key_id-name-y>._DUK. <zone-name-b> | |
Dynamic update key required to initiate a dynamic update request to <zone-name-b> using the <key_id-name-y> key. |