Services to check external IP address and to check IP addresses in common

https://ident.me/ - Get current IP address. Main domain shows IP address the was used to make a request, IPv4 or IPv6. Also, it has ipv4 (https://ipv4.ident.me/) and ipv6 (https://ipv6.ident.me/) subdomains to get IP address of exact IP protocol version


https://whatismyipaddress.com/ - different checks available

https://ip-api.com/ - nice site, provides detailed info about IP and also has an API

http://www.networktunnel.net/php/echoyourip.php - just faced it on the Internet. IP shows, but the country is defined wrong.