Dig

dig (Domain Information Groper) queries DNS servers and returns detailed information about DNS records. It is the standard tool for DNS troubleshooting on Linux.

Basic Lookup


# Look up the A record for a domain
dig example.com
 
# Short output — just the answer
dig example.com +short

Query Specific Record Types


dig example.com A       # IPv4 address
dig example.com AAAA    # IPv6 address
dig example.com MX      # Mail exchange
dig example.com TXT     # TXT records (SPF, DKIM, etc.)
dig example.com NS      # Name servers
dig example.com CNAME   # Canonical name
dig example.com SOA     # Start of authority

Query a Specific DNS Server


# Query Cloudflare's DNS
dig @1.1.1.1 example.com
 
# Query Google's DNS
dig @8.8.8.8 example.com
 
# Useful for comparing responses between DNS servers
dig @1.1.1.1 example.com +short
dig @8.8.8.8 example.com +short

Reverse Lookup


# Resolve an IP address back to a hostname
dig -x 8.8.8.8
 
# Short output
dig -x 8.8.8.8 +short

Trace the Full Resolution Path


# Follow the full delegation chain from root servers down
dig example.com +trace

Check DNS Propagation

After making DNS changes, compare responses across multiple resolvers to verify propagation:


for server in 1.1.1.1 8.8.8.8 9.9.9.9; do
  echo "=== $server ==="
  dig @$server example.com A +short
done