deviceA $ syncthing 
[start] 15:36:16 INFO: syncthing v1.19.1 "Fermium Flea" (go1.17.7 linux-amd64) deb@build.syncthing.net 2022-02-21 13:57:21 UTC [noupgrade]
[IV6CX] 15:36:16 INFO: My ID: IV6CXW4-6VQWQD6-5CEN7UE-KZPL7SO-PJOA3UU-LV7WFXY-DIAUEBJ-5VBCIAR
[IV6CX] 15:36:17 INFO: Single thread SHA256 performance is 319 MB/s using crypto/sha256 (317 MB/s using minio/sha256-simd).
[IV6CX] 15:36:17 INFO: Hashing performance is 244.07 MB/s
[IV6CX] 15:36:17 INFO: Overall send rate is unlimited, receive rate is unlimited
2022/03/10 15:36:17 failed to sufficiently increase receive buffer size (was: 208 kiB, wanted: 2048 kiB, got: 416 kiB). See https://github.com/lucas-clemente/quic-go/wiki/UDP-Receive-Buffer-Size for details.
[IV6CX] 15:36:17 INFO: Relay listener (dynamic+https://relays.syncthing.net/endpoint) starting
[IV6CX] 15:36:17 INFO: Using discovery mechanism: global discovery server https://discovery.syncthing.net/v2/?noannounce&id=LYXKCHX-VI3NYZR-ALCJBHF-WMZYSPK-QG6QJA3-MPFYMSO-U56GTUK-NA2MIAW
[IV6CX] 15:36:17 INFO: Using discovery mechanism: global discovery server https://discovery-v4.syncthing.net/v2/?nolookup&id=LYXKCHX-VI3NYZR-ALCJBHF-WMZYSPK-QG6QJA3-MPFYMSO-U56GTUK-NA2MIAW
[IV6CX] 15:36:17 INFO: Using discovery mechanism: global discovery server https://discovery-v6.syncthing.net/v2/?nolookup&id=LYXKCHX-VI3NYZR-ALCJBHF-WMZYSPK-QG6QJA3-MPFYMSO-U56GTUK-NA2MIAW
[IV6CX] 15:36:17 INFO: Using discovery mechanism: IPv4 local broadcast discovery on port 21027
[IV6CX] 15:36:17 INFO: Using discovery mechanism: IPv6 local multicast discovery on address [ff12::8384]:21027
[IV6CX] 15:36:17 INFO: TCP listener ([::]:22000) starting
[IV6CX] 15:36:17 INFO: QUIC listener ([::]:22000) starting
[IV6CX] 15:36:17 INFO: GUI and API listening on 127.0.0.1:8384
[IV6CX] 15:36:17 INFO: Access the GUI via the following URL: http://127.0.0.1:8384/
[IV6CX] 15:36:17 INFO: My name is "deviceA"
[IV6CX] 15:36:17 INFO: Device CYV3HUA-LJNFR6S-7M4MCZ2-EGACII6-3EUB6NI-FLQNAOW-HBQLY72-UEJVHA6 is "deviceB" at [dynamic]
[IV6CX] 15:36:18 INFO: quic://0.0.0.0:22000 detected NAT type: Full cone NAT
[IV6CX] 15:36:18 INFO: quic://0.0.0.0:22000 resolved external address quic://92.213.92.65:61239 (via stun.syncthing.net:3478)
[IV6CX] 15:36:28 INFO: Detected 3 NAT services
[IV6CX] 15:36:57 INFO: Joined relay relay://185.75.118.191:22067
[IV6CX] 15:37:11 INFO: Established secure connection to CYV3HUA-LJNFR6S-7M4MCZ2-EGACII6-3EUB6NI-FLQNAOW-HBQLY72-UEJVHA6 at 192.168.2.35:22000-192.168.2.2:22000/tcp-server/TLS1.3-TLS_CHACHA20_POLY1305_SHA256
[IV6CX] 15:37:11 INFO: Device CYV3HUA-LJNFR6S-7M4MCZ2-EGACII6-3EUB6NI-FLQNAOW-HBQLY72-UEJVHA6 client is "syncthing v1.19.1" named "deviceB" at 192.168.2.35:22000-192.168.2.2:22000/tcp-server/TLS1.3-TLS_CHACHA20_POLY1305_SHA256
[IV6CX] 15:37:12 INFO: Failed to exchange Hello messages with CYV3HUA-LJNFR6S-7M4MCZ2-EGACII6-3EUB6NI-FLQNAOW-HBQLY72-UEJVHA6 at [fe80::1a3d:a2ff:fec9:8b69%wlp2s0]:22000-[fe80::d8:4ff:fe02:fb4f%wlp2s0]:22000/tcp-server/TLS1.3-TLS_CHACHA20_POLY1305_SHA256: write tcp [fe80::1a3d:a2ff:fec9:8b69%wlp2s0]:22000->[fe80::d8:4ff:fe02:fb4f%wlp2s0]:22000: write: connection reset by peer


deviceB $ syncthing
[start] 15:37:07 INFO: syncthing v1.19.1 "Fermium Flea" (go1.17.7 linux-arm) deb@build.syncthing.net 2022-02-21 13:57:21 UTC [noupgrade]
[CYV3H] 15:37:08 INFO: My ID: CYV3HUA-LJNFR6S-7M4MCZ2-EGACII6-3EUB6NI-FLQNAOW-HBQLY72-UEJVHA6
[CYV3H] 15:37:08 INFO: Single thread SHA256 performance is 10 MB/s using minio/sha256-simd (10 MB/s using crypto/sha256).
[CYV3H] 15:37:09 INFO: Hashing performance is 9.13 MB/s
[CYV3H] 15:37:09 INFO: Overall send rate is unlimited, receive rate is unlimited
[CYV3H] 15:37:09 INFO: Using discovery mechanism: global discovery server https://discovery.syncthing.net/v2/?noannounce&id=LYXKCHX-VI3NYZR-ALCJBHF-WMZYSPK-QG6QJA3-MPFYMSO-U56GTUK-NA2MIAW
[CYV3H] 15:37:09 INFO: Using discovery mechanism: global discovery server https://discovery-v4.syncthing.net/v2/?nolookup&id=LYXKCHX-VI3NYZR-ALCJBHF-WMZYSPK-QG6QJA3-MPFYMSO-U56GTUK-NA2MIAW
[CYV3H] 15:37:09 INFO: Using discovery mechanism: global discovery server https://discovery-v6.syncthing.net/v2/?nolookup&id=LYXKCHX-VI3NYZR-ALCJBHF-WMZYSPK-QG6QJA3-MPFYMSO-U56GTUK-NA2MIAW
[CYV3H] 15:37:09 INFO: Using discovery mechanism: IPv4 local broadcast discovery on port 21027
[CYV3H] 15:37:09 INFO: Using discovery mechanism: IPv6 local multicast discovery on address [ff12::8384]:21027
[CYV3H] 15:37:09 INFO: Relay listener (dynamic+https://relays.syncthing.net/endpoint) starting
2022/03/10 15:37:09 failed to sufficiently increase receive buffer size (was: 176 kiB, wanted: 2048 kiB, got: 352 kiB). See https://github.com/lucas-clemente/quic-go/wiki/UDP-Receive-Buffer-Size for details.
[CYV3H] 15:37:09 INFO: TCP listener ([::]:22000) starting
[CYV3H] 15:37:09 INFO: QUIC listener ([::]:22000) starting
[CYV3H] 15:37:09 INFO: GUI and API listening on [::]:8384
[CYV3H] 15:37:09 INFO: Access the GUI via the following URL: http://127.0.0.1:8384/
[CYV3H] 15:37:09 INFO: My name is "deviceB"
[CYV3H] 15:37:09 INFO: Device IV6CXW4-6VQWQD6-5CEN7UE-KZPL7SO-PJOA3UU-LV7WFXY-DIAUEBJ-5VBCIAR is "deviceA" at [dynamic]
[CYV3H] 15:37:09 INFO: Device SBROZYR-BAEAAKQ-CFX7ZXR-D5S52N6-WK2K5IE-6KL54ZL-NW4ZZI2-YP4D3QR is "deviceC" at [dynamic]
[CYV3H] 15:37:10 INFO: quic://0.0.0.0:22000 detected NAT type: Full cone NAT
[CYV3H] 15:37:10 INFO: quic://0.0.0.0:22000 resolved external address quic://92.213.92.65:22000 (via stun.syncthing.net:3478)
[CYV3H] 15:37:11 INFO: Established secure connection to IV6CXW4-6VQWQD6-5CEN7UE-KZPL7SO-PJOA3UU-LV7WFXY-DIAUEBJ-5VBCIAR at 192.168.2.2:22000-192.168.2.35:22000/tcp-client/TLS1.3-TLS_CHACHA20_POLY1305_SHA256
[CYV3H] 15:37:11 INFO: Device IV6CXW4-6VQWQD6-5CEN7UE-KZPL7SO-PJOA3UU-LV7WFXY-DIAUEBJ-5VBCIAR client is "syncthing v1.19.1" named "deviceA" at 192.168.2.2:22000-192.168.2.35:22000/tcp-client/TLS1.3-TLS_CHACHA20_POLY1305_SHA256
[CYV3H] 15:37:20 INFO: Detected 3 NAT services
[CYV3H] 15:37:47 INFO: Joined relay relay://91.121.221.176:10007
[CYV3H] 15:38:10 INFO: Established secure connection to SBROZYR-BAEAAKQ-CFX7ZXR-D5S52N6-WK2K5IE-6KL54ZL-NW4ZZI2-YP4D3QR at 192.168.2.2:22000-192.168.2.22:22000/tcp-server/TLS1.3-TLS_CHACHA20_POLY1305_SHA256
[CYV3H] 15:38:10 INFO: Device SBROZYR-BAEAAKQ-CFX7ZXR-D5S52N6-WK2K5IE-6KL54ZL-NW4ZZI2-YP4D3QR client is "syncthing v1.19.1" named "deviceC" at 192.168.2.2:22000-192.168.2.22:22000/tcp-server/TLS1.3-TLS_CHACHA20_POLY1305_SHA256
[CYV3H] 15:39:19 INFO: Ready to synchronize "Default Folder" (default) (sendreceive)
[CYV3H] 15:39:19 INFO: Device SBROZYR folder "Default Folder" (default) has a new index ID (0x4418F325AB154929)
[CYV3H] 15:39:19 INFO: Unpaused folder "Default Folder" (default) (sendreceive)
[CYV3H] 15:39:20 INFO: Completed initial scan of sendreceive folder "Default Folder" (default)


deviceC $ syncthing
[start] 15:38:07 INFO: syncthing v1.19.1 "Fermium Flea" (go1.17.7 linux-amd64) deb@build.syncthing.net 2022-02-21 13:57:21 UTC [noupgrade]
[SBROZ] 15:38:07 INFO: My ID: SBROZYR-BAEAAKQ-CFX7ZXR-D5S52N6-WK2K5IE-6KL54ZL-NW4ZZI2-YP4D3QR
[SBROZ] 15:38:08 INFO: Single thread SHA256 performance is 163 MB/s using crypto/sha256 (163 MB/s using minio/sha256-simd).
[SBROZ] 15:38:08 INFO: Hashing performance is 149.94 MB/s
[SBROZ] 15:38:08 INFO: Overall send rate is unlimited, receive rate is unlimited
[SBROZ] 15:38:08 INFO: Ready to synchronize "Default Folder" (default) (sendreceive)
[SBROZ] 15:38:08 INFO: Using discovery mechanism: global discovery server https://discovery.syncthing.net/v2/?noannounce&id=LYXKCHX-VI3NYZR-ALCJBHF-WMZYSPK-QG6QJA3-MPFYMSO-U56GTUK-NA2MIAW
[SBROZ] 15:38:08 INFO: Using discovery mechanism: global discovery server https://discovery-v4.syncthing.net/v2/?nolookup&id=LYXKCHX-VI3NYZR-ALCJBHF-WMZYSPK-QG6QJA3-MPFYMSO-U56GTUK-NA2MIAW
[SBROZ] 15:38:08 INFO: Using discovery mechanism: global discovery server https://discovery-v6.syncthing.net/v2/?nolookup&id=LYXKCHX-VI3NYZR-ALCJBHF-WMZYSPK-QG6QJA3-MPFYMSO-U56GTUK-NA2MIAW
[SBROZ] 15:38:08 INFO: Using discovery mechanism: IPv4 local broadcast discovery on port 21027
[SBROZ] 15:38:08 INFO: Using discovery mechanism: IPv6 local multicast discovery on address [ff12::8384]:21027
[SBROZ] 15:38:08 INFO: Relay listener (dynamic+https://relays.syncthing.net/endpoint) starting
2022/03/10 15:38:08 failed to sufficiently increase receive buffer size (was: 208 kiB, wanted: 2048 kiB, got: 416 kiB). See https://github.com/lucas-clemente/quic-go/wiki/UDP-Receive-Buffer-Size for details.
[SBROZ] 15:38:08 INFO: TCP listener ([::]:22000) starting
[SBROZ] 15:38:08 INFO: QUIC listener ([::]:22000) starting
[SBROZ] 15:38:08 INFO: GUI and API listening on 127.0.0.1:8384
[SBROZ] 15:38:08 INFO: Access the GUI via the following URL: http://127.0.0.1:8384/
[SBROZ] 15:38:08 INFO: My name is "deviceC"
[SBROZ] 15:38:08 INFO: Device CYV3HUA-LJNFR6S-7M4MCZ2-EGACII6-3EUB6NI-FLQNAOW-HBQLY72-UEJVHA6 is "deviceB" at [dynamic]
[SBROZ] 15:38:08 INFO: Completed initial scan of sendreceive folder "Default Folder" (default)
[SBROZ] 15:38:10 INFO: Established secure connection to CYV3HUA-LJNFR6S-7M4MCZ2-EGACII6-3EUB6NI-FLQNAOW-HBQLY72-UEJVHA6 at 192.168.2.22:22000-192.168.2.2:22000/tcp-client/TLS1.3-TLS_CHACHA20_POLY1305_SHA256
[SBROZ] 15:38:10 INFO: Device CYV3HUA-LJNFR6S-7M4MCZ2-EGACII6-3EUB6NI-FLQNAOW-HBQLY72-UEJVHA6 client is "syncthing v1.19.1" named "deviceB" at 192.168.2.22:22000-192.168.2.2:22000/tcp-client/TLS1.3-TLS_CHACHA20_POLY1305_SHA256
[SBROZ] 15:38:19 INFO: Detected 3 NAT services
[SBROZ] 15:38:28 INFO: quic://0.0.0.0:22000 detected NAT type: Port restricted NAT
[SBROZ] 15:38:28 INFO: quic://0.0.0.0:22000 resolved external address quic://92.213.92.65:61277 (via stun.syncthing.net:3478)
[SBROZ] 15:38:46 INFO: Joined relay relay://151.80.43.167:22067
[SBROZ] 15:39:19 INFO: Device CYV3HUA folder "Default Folder" (default) has a new index ID (0xD012B0CB9F1B46D7)