Bind9 Equivalent to Dnsmasq's Resolv-File Option

If you're a system administrator, you're probably familiar with the resolv-file option in the Dnsmasq DHCP server. This option allows you to specify a custom file for the DHCP server to use for DNS resolution. But what if you're using BIND9 instead of Dnsmasq? Is there an equivalent option for BIND9?

The answer is yes, there is an equivalent option in BIND9. It's called the forwarders option in the options section of the BIND9 configuration file. In this article, we'll show you how to use the forwarders option in BIND9 to achieve the same result as the resolv-file option in Dnsmasq.

What is the forwarders Option in BIND9?

The forwarders option in BIND9 is used to specify a list of DNS servers that the BIND9 DNS server should forward queries to. The DNS servers specified in the forwarders option will be used for all queries, unless the query matches a zone defined in the BIND9 configuration file. In that case, the query will be resolved using the zone data instead of being forwarded.

The forwarders option is specified in the options section of the BIND9 configuration file. The options section is used to specify global options for the BIND9 DNS server. Here's an example of how to use the forwarders option in BIND9:

options {
  forwarders {
    8.8.8.8;
    8.8.4.4;
  };
};

In this example, the BIND9 DNS server will forward all queries to the Google DNS servers at 8.8.8.8 and 8.8.4.4. You can specify as many DNS servers as you want, separated by semicolons. If you want to use a local DNS server instead of a public one, just replace the IP addresses with the IP addresses of your local DNS servers.

How to Use the forwarders Option in BIND9

Using the forwarders option in BIND9 is easy. Just follow these steps:

1. Open the BIND9 configuration file. The location of the configuration file depends on your operating system. On Ubuntu, the configuration file is located at /etc/bind/named.conf.
2. Add the forwarders option to the options section of the configuration file. Here's an example:

options {
  directory "/var/cache/bind";

  // If there is a firewall between you and nameservers you want
  // to talk to, you may need to fix the firewall to allow multiple
  // ports to talk. See http://www.kb.cert.org/vuls/id/800113

  // If your ISP provided one or more IP addresses for stable
  // nameservers, you probably want to use them as forwarders.
  // Uncomment the following block, and insert the addresses replacing
  // the all-0's placeholder.

  forwarders {
    8.8.8.8;
    8.8.4.4;
  };

  //========================================================================
  // If BIND logs error messages about the root key being expired,
  // you will need to update your keys. See https://www.isc.org/bind-keys
  //========================================================================
  dnssec-validation auto;

  auth-nxdomain no;    # conform to RFC1035
  listen-on-v6 { any; };
};

In this example, the BIND9 DNS server will forward all queries to the Google DNS servers at 8.8.8.8 and 8.8.4.4. You can replace the IP addresses with the IP addresses of your local DNS servers if you want to use a local DNS server instead of a public one.

3. Save the changes and exit the text editor. 4. Restart the BIND9 DNS server to apply the changes. On Ubuntu, you can use the following command to restart BIND9:

sudo systemctl restart bind9

5. Test the changes to make sure they're working properly. You can use the dig command to test the DNS resolution. Here's an example:

dig www.google.com

The dig command should return the IP address of the Google website. If it does, the forwarders option is working properly.

The forwarders option in BIND9 is the equivalent of the resolv-file option in Dnsmasq. It allows you to specify a list of DNS servers that the BIND9 DNS server should forward queries to. Using the forwarders option in BIND9 is easy, and it can be done in just a few steps. If you're using BIND9 instead of Dnsmasq, the forwarders option is the way to go.

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