• The issue is present in the latest release.
• I have searched the issues of this repository and believe that this is not a duplicate.

What happened?

If you have IPv6 configured and set

udp_bind = "0.0.0.0:1700" 

in your /etc/chirpstack-gateway-bridge/chirpstack-gateway-bridge.toml file (this isthe default setting),
ChirpStack Gateway Bridge binds to ipv6 socket only:

# netstat -lnup | grep 1700 udp6 0 0 :::1700 :::* 4077/chirpstack-gat

If you set a valid IPv4 socket, it binds only to it as expected.

Tested with the latest precompiled Debian binaries.

What did you expect?

It binds only IPv4 socket or both IPv4 and IPv6.

Steps to reproduce this issue

Steps:

1. Set up an IPv4 end IPv6 dual stack configuration with static adresses.
2. Leave udp_bind parameter on the default 0.0.0.0:1700 value.
3. See if it binds to the IPv4 socket.

Could you share your log output?

# chirpstack-gateway-bridge -c /etc/chirpstack-gateway-bridge/chirpstack-gateway-bridge.toml INFO[0000] starting ChirpStack Gateway Bridge docs="https://www.chirpstack.io/gateway-bridge/" version=4.0.11 INFO[0000] backend/semtechudp: starting gateway udp listener addr="0.0.0.0:1700" WARN[0000] [store] memorystore wiped module=mqtt INFO[0000] integration/mqtt: connected to mqtt broker

Your Environment