Accessing an IPv6 server with an IPv4 address?

Solution 1:

An IPv6 tunnel broker is a service that provides you with IPv6 connectivity on networks where you only have IPv4. As IPv4 addresses are very scarce these days it is unlikely that someone will let you use an IPv4 address for free. Your best bet is to rent a (virtual) server somewhere that has both IPv4 and IPv6 and then use tools like haproxy to forward incoming connections over IPv4 to your machine over IPv6.

Such workarounds are necessary until every network properly supports IPv6. A lot of people have been pushing ISPs and enterprises for many many years to deploy IPv6 so that workarounds like this wouldn't be necessary. Unfortunately a lot of networks still don't have IPv6 which is why it is now difficult for those of us who don't have IPv4 addresses anymore to keep things reachable.

Once most networks support IPv6 you can just use IPv6 everywhere. Until then: keep making it clear to network operators that only offer IPv4 how much trouble they are causing and encourage them to deploy IPv6.