The `awk` Command
To determine whether a website is using only IPv6 or if it supports both IPv4 and IPv6 (dual stack), you can do:
a. Use ping
# To ping via IPv6
ping6 example.com
# To ping via IPv4
ping example.com
If only the IPv6 ping is successful, the site might not support IPv4.
b. Use nslookup
with -type
# Check for IPv6 address
nslookup -type=AAAA example.com
# Check for IPv4 address
nslookup -type=A example.com
If only the AAAA record returns an address and the A record returns nothing, the site may only use IPv6.
c. Use dig
The dig
command provides a detailed DNS query. You can check for both address records:
# For IPv6
dig AAAA example.com
# For IPv4
dig A example.com
Again, if only the AAAA record has an entry and the A record does not, the site probably just supports IPv6.
d. Use curl
curl -I -6 http://example.com # For IPv6
curl -I -4 http://example.com # For IPv4
2. Using Online Tools
There are several online tools that can help you check a domain's IPv4 and IPv6 support: - MXToolbox (https://mxtoolbox.com): Allows you to check DNS records, including A and AAAA. - DNSChecker (https://dnschecker.org): Provides a global view of DNS records, including IPv4 and IPv6. - WhatIsMyIPAddress (https://whatismyipaddress.com): Offers tools to check if a site is reachable via IPv4 or IPv6.