A very useful package for testing and troubleshooting DNS issues is the dnsutils package. Some of the most useful setups are: Caching Server In this configuration BIND9 will find the answer to name queries and remember the answer for the next query.
This can be useful for a slow internet connection. By caching DNS queries, you will reduce bandwidth and more importantly latency. Primary Master Server BIND9 can be used to serve DNS records groups of records are referred to as zones for a registered domain name or an imaginary one but only if used on a restricted network.
Secondary Master Server A secondary master DNS server is used to complement a primary master DNS server by serving a copy of the zone s configured on the primary server. Secondary servers are recommended in larger setups. If you intend to serve a registered domain name they ensure that your DNS zone is still available even if your primary server is not online. All that is required is simply combining the different configuration examples.
These are effectively the same as Primary and Secondary DNS servers, but with a slight organizational difference. A is the Primary, B and C are secondaries. It's still a secondary, but it's not going to be asked about the zone you are serving to the internet from A and B If you configure your registered domain to use B and C as your domain's DNS servers, then A is a stealth primary.
Any additional records or edits to the zone are done on A, but computers on the internet will only ever ask B and C about the zone. Address Records The most commonly used type of record. This record maps an IP Address to a hostname. But it doubles the number of requests made to the nameserver, thus making it an inefficient way to do so. Multiple MX records can exist if multiple mail servers are responsible for that domain. IN MX 10 mail. This is where Primary and Secondary servers are defined.
Stealth servers are intentionally omitted. IN NS ns. This is due to the server caching the query. Any host label within a record that uses a fully qualified domain terminating with an ending period will not append the origin hostname. This is typically used for the apex of a zone. A Start Of Authority record is required for each zone. A zone file is a collection of resource records with each record entry described in the following sequence:.
Hostmaster Email — Address of the party responsible for the zone. Serial Number — Version number of the zone. This is where BIND has a role to play. Above all, this open-source software allows a user to publish the DNS information on the Internet.
Hence it resolves DNS queries quickly. The named is the service that executes the DNS server daemon. The default port of the named service is A zone file is a text-based file stored in a DNS server. This file contains the mapping between the domain name and IP address. A zone file can be a DNS master file or a file authoritatively describing a zone.
The file usually contains A record, MX record, domain name, mail servers, nameservers details and so on. So, this file is critically important as it holds the domain details. Any error in this file can cause trouble while loading the domain. Because DNS lookup resolves a domain with the help of this zone file. A zone file is a text file so it can contain syntax errors. Hence we need to check the syntax and integrity of this important configuration file. For this, we can make use of the command, named-checkzone.
Alternatively, we can check the configuration file of BIND. For this, we can make use of the command, named-checkconf. The command usage is as,. In short, to check the BIND9 zone file we can use the command named-checkzone.
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