Some Open DNS operators provide a way to return the IP address of the request packet.

Google DNS:

dig o-o.myaddr.l.google.com txt @ns1.google.com +short

OpenDNS:

dig myip.opendns.com @resolver1.opendns.com +short

Akamai:

$ dig +short TXT whoami.ds.akahelp.net
"ns" "2001:db8::abcd"
"ecs" "203.0.113.0/24/0"
"ip" "203.0.113.132"

The ds stands for dual stack. It is also reachable under whoami.ipv6.akahelp.net to force IPv6 or whoami.ipv4.akahelp.net to force IPv4.

ns stands for the unicast IP address of the recursive resolver. ecs contains the EDNS client subnet information, if the option is used by the resolver. In this case ip contains a representative IP within the ECS, not necessarily the IP of the client.

The new version is introduced in this blog post https://www.akamai.com/blog/developers/introducing-new-whoami-tool-dns-resolver-information.

The old version might be decomissioned:

dig whoami.akamai.net. @ns1-1.akamaitech.net. +short

Source

Get your public IP using DNS