alt Hacker NewsOr, you could've fixed your server's configuration. Probably would've been faster than to "disable, remove and nuke ipv6". In general, the mistake is that it says "0.0.0.0" or "0.0.0.0:8080" somewhere where it should really say "::" or "[::]:8080".
(IPv6 sockets by default accept IPv4 connections, unless you disable that either system-wide or on the specific socket.)
By the way, I do agree the colon was a really poor choice for separating the blocks, when it is also used to separate the port number.
I fixed the problem once for all. Now my program even refuses to start, if IPv6 is enabled. I am not going to spend time debugging problem, that can be easily prevented. Pretty valid solution on private networks and local only kubernetes deployments.
If customer wants proper ipv6 support, we can sign a contract and talk about it. But do not expect me to support some technology for free, just because it is enabled by default.