Linux dig Command: Simple DNS Lookup Examples

#networking #linux #dns #devops

The dig (Domain Information Groper) command helps developers check DNS records and troubleshoot domain resolution on Linux. It is one of the first tools to reach for when a domain isn't behaving the way you expect.

1. Install dig

On Debian/Ubuntu-based systems, dig ships in the dnsutils package:

sudo apt update
sudo apt install dnsutils

2. Find a Domain's IP Address

dig safal.me +short

The +short flag trims the output down to just the IP addresses found in the DNS response.

3. Check DNS Records

Pass a record type after the domain name:

dig safal.me A
dig safal.me AAAA
dig safal.me MX
dig safal.me NS
dig safal.me TXT

Record	Purpose
`A`	IPv4 address
`AAAA`	IPv6 address
`MX`	Mail servers
`NS`	Name servers
`TXT`	Text records (SPF, domain verification, etc.)

4. Query a Specific DNS Server

dig @8.8.8.8 safal.me

This sends the query to Google's public DNS resolver instead of your system default, which is handy for checking whether a problem is local to your resolver.

5. Trace DNS Resolution

dig safal.me +trace

This shows the delegation process step by step, from the root servers down to the domain's authoritative name servers.

Conclusion

The dig command is a useful tool for developers and DevOps engineers troubleshooting DNS issues. Once you know these few flags, most DNS debugging becomes quick and predictable.

Next: Linux nslookup Command: Simple Examples.