neither Mini Program nor H5's client code can obtain the ip address, but both can obtain the ip on the server side. The method of obtaining the ip on the server side depends on the server used.

of course, if you are developing in Wechat, you can try to use Wechat's own authorization mechanism, so that a large number of malicious requests can be filtered through Wechat's authorization mechanism. Instead of letting your server filter directly

Mini Program does not understand that the client ip address can be obtained by sending a request to some websites, such as ifconfig.me, but it is only a public network address.

. Learn the TCP/IP protocol

you confirm one thing first. When a user initiates a CAPTCHA request, is it client-> SMS server or client-> Wechat server-> SMS server