dig command
Detailed Explanation
dig (Domain Information Groper) is a flexible command-line tool for interrogating DNS name servers. It performs DNS lookups and displays the answers that are returned from the name servers. Most DNS administrators use dig to troubleshoot DNS problems because of its flexibility, ease of use, and clarity of output.
Basic Syntax
dig [@server] [domain] [type] [options]
Common Flags/Options
| Option | Description |
|---|---|
+short | Provide a terse answer (just the data). |
+trace | Trace the delegation path from the root name servers to the destination. |
+noall +answer | Hide all output except the actual answer section. |
-x <ip_address> | Perform a reverse DNS lookup. |
Real-world Examples
Standard DNS lookup (A record):
dig example.com
Query a specific record type (e.g., TXT):
dig example.com TXT
Get only the IP address (short output):
dig +short example.com
Query using a specific DNS server (e.g., Google's 8.8.8.8):
dig @8.8.8.8 example.com
Perform a reverse lookup:
dig -x 8.8.8.8