dig Command in Linux

Syntax of dig Command in Linux

The basic syntax of the dig command in Linux is as follows:

Where:

• @server: This is the name or IP address of the DNS server that you wish to send the DNS query to. This is an optional part of the syntax.
• name: This is the name of the domain that you wish to investigate. This could be any domain, like 'google.com' or 'microsoft.com'.
• type: This indicates the type of the DNS record that you want to query. Examples could be 'A' (Address Record), 'MX' (Mail Exchange Record), 'NS' (Name Server Record), etc.

Options in dig Command in Linux

1. +short: This option provides a concise answer, stripping off the additional information.

   For example -

   Output:

   This command returns the IP address of 'google.com' without any additional information.

2. +trace: This option allows for a trace of the DNS path, showing the path that a DNS request takes to get to the server.

   For example -

   Output:

   This command returns the complete path that the DNS request takes to reach the 'google.com' server.

3. +nocmd: This option removes the initial comment section from the output.

   For example -

   Output:

   This command provides the DNS information of 'google.com', but without the initial command section.

Example Usages

• Basic use of dig to query the A record of a domain.:

  Output:

  Explanation: This command returns the A (Address) record of 'google.com', which typically includes the IP address among other information.

• Using dig to query the MX record of a domain.:

  Output:

  Explanation: This command returns the MX (Mail Exchange) record of 'google.com', which contains information about mail servers responsible for accepting emails on behalf of the domain.

Advanced Use Cases of dig Command in Linux

• Using dig to perform a reverse DNS lookup.:

  Output:

  Explanation: This command performs a reverse DNS lookup for the IP address '8.8.8.8', which often returns the hostname associated with the IP address.

• Using dig to query a specific DNS server.:

  Output:

  Explanation: This command sends the DNS query for 'google.com' specifically to the DNS server '8.8.8.8'.

• Using dig with the ANY option to get all available DNS records.:

  Output:

  Explanation: This command returns all available DNS records for 'google.com'. It's equivalent to performing multiple dig commands for each record type.