STUN server can become unresponsive #251
Description
It has happened twice so far. STUN server reaches a state where OpenTTD clients fail to connect. It appears to affect every server that uses STUN, and any client that tries to connect to such servers. Restarting the OpenTTD does not seem to have any effect.
First time it happened:
[2025-07-24 09:04:43] dbg: [net:9] NetworkClientConnectGame(): connection_string=+BWyCMXB
[2025-07-24 09:04:43] dbg: [net:5] Closed UDP listeners
[2025-07-24 09:04:43] dbg: [net:3] Initializing UDP listeners
[2025-07-24 09:04:43] dbg: [net:9] status = CONNECTING
[2025-07-24 09:04:43] dbg: [net:9] Stun::Connect(): family=10
[2025-07-24 09:04:43] dbg: [net:9] Stun::Connect(): family=2
[2025-07-24 09:04:43] dbg: [net:6] stun.openttd.org:3975 resolved in:
[2025-07-24 09:04:43] dbg: [net:6] - 3.254.230.109:3975 (IPv4)
[2025-07-24 09:04:43] dbg: [net:6] - 52.213.78.185:3975 (IPv4)
[2025-07-24 09:04:43] dbg: [net:6] stun.openttd.org:3975 resolved in:
[2025-07-24 09:04:43] dbg: [net:6] - [2a05:d018:5fd:4605:5234::1]:3975 (IPv6)
[2025-07-24 09:04:43] dbg: [net:6] - [2a05:d018:5fd:4604:4420::1]:3975 (IPv6)
[2025-07-24 09:04:43] dbg: [net:5] Attempting to connect to [2a05:d018:5fd:4605:5234::1]:3975 (IPv6)
[2025-07-24 09:04:43] dbg: [net:1] Could not connect to [2a05:d018:5fd:4605:5234::1]:3975 (IPv6): Network is unreachable
[2025-07-24 09:04:43] dbg: [net:5] Attempting to connect to 3.254.230.109:3975 (IPv4)
[2025-07-24 09:04:43] dbg: [net:5] Attempting to connect to [2a05:d018:5fd:4604:4420::1]:3975 (IPv6)
[2025-07-24 09:04:43] dbg: [net:1] Could not connect to [2a05:d018:5fd:4604:4420::1]:3975 (IPv6): Network is unreachable
[2025-07-24 09:04:43] dbg: [net:9] Stun::OnFailure(): family=10
[2025-07-24 09:04:43] dbg: [net:3] Connected to stun.openttd.org:3975
[2025-07-24 09:04:43] dbg: [net:5] - using 3.254.230.109:3975 (IPv4)
[2025-07-24 09:04:43] dbg: [net:9] Stun::OnConnect(): family=2
[2025-07-24 09:05:03] dbg: [net:9] Client::OnFailure(): connection_string=+BWyCMXB
Second time it happened:
[2025-08-23 21:54:34] dbg: [net:9] NetworkClientConnectGame(): connection_string=+BWyCMXB
[2025-08-23 21:54:34] dbg: [net:5] Closed UDP listeners
[2025-08-23 21:54:34] dbg: [net:3] Initializing UDP listeners
[2025-08-23 21:54:34] dbg: [net:9] status = CONNECTING
[2025-08-23 21:54:34] dbg: [net:9] Stun::Connect(): family=10
[2025-08-23 21:54:34] dbg: [net:9] Stun::Connect(): family=2
[2025-08-23 21:54:34] dbg: [net:6] stun.openttd.org:3975 resolved in:
[2025-08-23 21:54:34] dbg: [net:6] - [2a05:d018:5fd:4604:4420::1]:3975 (IPv6)
[2025-08-23 21:54:34] dbg: [net:6] - [2a05:d018:5fd:4605:5234::1]:3975 (IPv6)
[2025-08-23 21:54:34] dbg: [net:6] stun.openttd.org:3975 resolved in:
[2025-08-23 21:54:34] dbg: [net:6] - 3.254.230.109:3975 (IPv4)
[2025-08-23 21:54:34] dbg: [net:6] - 52.213.78.185:3975 (IPv4)
[2025-08-23 21:54:34] dbg: [net:5] Attempting to connect to [2a05:d018:5fd:4604:4420::1]:3975 (IPv6)
[2025-08-23 21:54:34] dbg: [net:1] Could not connect to [2a05:d018:5fd:4604:4420::1]:3975 (IPv6): Network is unreachable
[2025-08-23 21:54:34] dbg: [net:5] Attempting to connect to 3.254.230.109:3975 (IPv4)
[2025-08-23 21:54:34] dbg: [net:5] Attempting to connect to [2a05:d018:5fd:4605:5234::1]:3975 (IPv6)
[2025-08-23 21:54:34] dbg: [net:1] Could not connect to [2a05:d018:5fd:4605:5234::1]:3975 (IPv6): Network is unreachable
[2025-08-23 21:54:34] dbg: [net:9] Stun::OnFailure(): family=10
[2025-08-23 21:54:34] dbg: [net:3] Connected to stun.openttd.org:3975
[2025-08-23 21:54:34] dbg: [net:5] - using 3.254.230.109:3975 (IPv4)
[2025-08-23 21:54:34] dbg: [net:9] Stun::OnConnect(): family=2
[2025-08-23 21:54:43] dbg: [net:5] Closed UDP listeners
[2025-08-23 21:54:43] dbg: [net:3] Initializing UDP listeners