Some Open DNS operators provide a way to return the IP address of the request packet.
dig o-o.myaddr.l.google.com txt @ns1.google.com +short
dig myip.opendns.com @resolver1.opendns.com +short
$ dig +short TXT whoami.ds.akahelp.net "ns" "2001:db8::abcd" "ecs" "203.0.113.0/24/0" "ip" "203.0.113.132"
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