web ui only listen ipv6 address

[Wanxp]

problem: can not visit web ui from http://ip:9876

ubuntu: 24.04
docker: 27.3.1
start cmd

docker run -d --name ddns-go --restart=always --net=host -v /opt/ddns-go:/root waterlemons2k/ddns-go

result:

netstat -nlp | grep 9876

out put

tcp6       0      0 :::9876                 :::*                    LISTEN      80686/ddns-go       

[WaterLemons2k]

problem: can not visit web ui from http://ip:9876/

I think it might be a firewall issue, check ufw or something.
And make sure you can connect to it with curl on the host first:

curl -v localhost:9876

---

net.Listen will listen on both IPv4 and IPv6, as this app uses the tcp network:
https://github.com/jeessy2/ddns-go/blob/v6.7.6/main.go#L197

Also a common problem in Go:
golang/go#9334
golang/go#17615
golang/go#48723
hashicorp/nomad#10189
mholt/caddy-l4#47

---

result:

netstat -nlp | grep 9876

out put

tcp6       0      0 :::9876                 :::*                    LISTEN      80686/ddns-go       

This is a false positive from netstat (https://stackoverflow.com/a/58839676), so don't worry.