Android stays disconnected

Hi,

My FairPhone 5 is no longer able to connect to my Linux box. Nothing has changed with regards to my network configurations, so I’m a bit at a loss at what could have caused the issue.

Log output from this morning after restarting syncthing:

--------- beginning of main
01-31 07:14:17.967 I/SyncthingNativeCode( 7165): [V5RX5] INFO: QUIC listener ([::]:22000) shutting down
01-31 07:14:17.968 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Relay listener (dynamic+https://relays.syncthing.net/endpoint) shutting down
01-31 07:14:18.401 I/SyncthingNativeCode( 7165): [V5RX5] INFO: TCP listener ([::]:22000) shutting down
01-31 07:14:18.409 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Exiting
01-31 07:14:19.165 I/SyncthingNativeCode( 7165): [start] INFO: syncthing v1.27.2 "Gold Grasshopper" (go1.20.11 android-arm64) vagrant@bullseye 2023-12-25 03:45:16 UTC [noupgrade, stguiassets, sthashing, stnoupgrade]
01-31 07:14:19.194 I/SyncthingNativeCode( 7165): [V5RX5] INFO: My ID: V5RX5SE-OUYVZKX-RU7WVQ5-KK4UWBO-TOLMIWS-34NXA4H-3RIKDQA-JMBGEQE
01-31 07:14:19.652 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Hashing performance is 847.57 MB/s
01-31 07:14:19.652 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Overall send rate is unlimited, receive rate is unlimited
01-31 07:14:19.654 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Using discovery mechanism: global discovery server https://discovery.syncthing.net/v2/?noannounce&id=LYXKCHX-VI3NYZR-ALCJBHF-WMZYSPK-QG6QJA3-MPFYMSO-U56GTUK-NA2MIAW
01-31 07:14:19.655 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Using discovery mechanism: global discovery server https://discovery-v4.syncthing.net/v2/?nolookup&id=LYXKCHX-VI3NYZR-ALCJBHF-WMZYSPK-QG6QJA3-MPFYMSO-U56GTUK-NA2MIAW
01-31 07:14:19.655 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Using discovery mechanism: global discovery server https://discovery-v6.syncthing.net/v2/?nolookup&id=LYXKCHX-VI3NYZR-ALCJBHF-WMZYSPK-QG6QJA3-MPFYMSO-U56GTUK-NA2MIAW
01-31 07:14:19.655 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Using discovery mechanism: IPv4 local broadcast discovery on port 21027
01-31 07:14:19.655 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Using discovery mechanism: IPv6 local multicast discovery on address [ff12::8384]:21027
01-31 07:14:19.656 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Relay listener (dynamic+https://relays.syncthing.net/endpoint) starting
01-31 07:14:19.656 I/SyncthingNativeCode( 7165): [V5RX5] INFO: QUIC listener ([::]:22000) starting
01-31 07:14:19.656 I/SyncthingNativeCode( 7165): [V5RX5] INFO: TCP listener ([::]:22000) starting
01-31 07:14:19.656 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Listing network interfaces: route ip+net: netlinkrib: permission denied
01-31 07:14:19.656 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Detected 0 NAT services
01-31 07:14:19.656 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Ready to synchronize "Scans" (e5hti-b6pwm) (sendreceive)
01-31 07:14:19.657 I/SyncthingNativeCode( 7165): [V5RX5] INFO: GUI and API listening on 127.0.0.1:8384
01-31 07:14:19.658 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Access the GUI via the following URL: https://127.0.0.1:8384/
01-31 07:14:19.658 I/SyncthingNativeCode( 7165): [V5RX5] INFO: My name is "FP5"
01-31 07:14:19.658 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Device QPG5PJU-NWJ7XCK-RPAHGJT-GZYG2TU-6PKVORY-IWCXKAR-ADRNSKN-CHXX5AQ is "t480s" at [dynamic]
01-31 07:14:20.515 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Ready to synchronize "FP5/Camera" (e7dq3-ro6ja) (sendreceive)
01-31 07:14:20.573 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Ready to synchronize "Music" (oeshx-vnjuo) (receiveonly)
01-31 07:14:20.600 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Completed initial scan of sendreceive folder "Scans" (e5hti-b6pwm)
01-31 07:14:23.045 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Completed initial scan of sendreceive folder "FP5/Camera" (e7dq3-ro6ja)
01-31 07:14:23.463 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Completed initial scan of receiveonly folder "Music" (oeshx-vnjuo)
01-31 07:14:23.472 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Puller (folder "Music" (oeshx-vnjuo), item "CompulsoryListeningTest1"): syncing: symlink create: symlink /home/kf/emta/EarlyMusicHistory/CompulsoryListeningTest1 /storage/emulated/0/Music/CompulsoryListeningTest1: permission denied
01-31 07:14:23.473 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Puller (folder "Music" (oeshx-vnjuo), item "CompulsoryListeningTest2"): syncing: symlink create: symlink /home/kf/emta/EarlyMusicHistory/CompulsoryListeningTest2 /storage/emulated/0/Music/CompulsoryListeningTest2: permission denied
01-31 07:14:23.473 I/SyncthingNativeCode( 7165): [V5RX5] INFO: "Music" (oeshx-vnjuo): Failed to sync 2 items
01-31 07:14:23.473 I/SyncthingNativeCode( 7165): [V5RX5] INFO: Folder "Music" (oeshx-vnjuo) isn't making sync progress - retrying in 1m0s.

Android version 13, syncthing 1.27.1.

Settings:

It seems like that it just struggles creating the (attempted to be) synced symlinks. Afaik Android is a bit picky about it, should probably check if it’s actually supported in the specified location.

Hi Eric,

Unfortunately not. These symlinks have been there for a long time without causing a disconnect. I tried to remove them on the linux box now, just in case. In addition I tried to remove the linux system and re-adding it in the android app, all to no avail…

EDIT: Also tried removing the android device from linux and re-adding it. No luck.

Can you post screenshots of the Web GUI from both sides? On Android, you can access the Web GUI using the left slide-out menu. The important part is “Discovery” and “Listeners” under “This Device”.

android:

linux:

2024-01-31_14:49:06

Is global discovery enabled? How are you running syncthing on your Linux box?

Running it as a user systemd service… The android device popped up briefly when I allowed it to connect over mobile data a litte while ago, but haven’t seen it since, neither via 4G or LAN. I am suspecting that something is off with my network settings, though…

Global discovery i enabled.

Update… throwing stuff against the wall to see what sticks. Disabled NordVPN on both devices to see if this was the cause of the trouble. Apparently not, as it’s still not connecting. However, occasionally something’s coming through, f.x. requests from the linux side to share a folder. The folder is created on the android side, but after this nothing more happens.

Furthermore, this kind of activity shows up in the linux web-gui:

Don’t know if that helps…

Is global discovery enabled on your Linux box?

Yes

Could you check which addresses the phone is trying to dial?

Not exactly sure how to do that, but here’s the latest log:


2024-02-02 10:58:38 Hashing performance is 834.60 MB/s
2024-02-02 10:58:38 Overall send rate is unlimited, receive rate is unlimited
2024-02-02 10:58:38 Using discovery mechanism: global discovery server https://discovery.syncthing.net/v2/?noannounce&id=LYXKCHX-VI3NYZR-ALCJBHF-WMZYSPK-QG6QJA3-MPFYMSO-U56GTUK-NA2MIAW
2024-02-02 10:58:38 TCP listener ([::]:22000) starting
2024-02-02 10:58:38 Using discovery mechanism: global discovery server https://discovery-v4.syncthing.net/v2/?nolookup&id=LYXKCHX-VI3NYZR-ALCJBHF-WMZYSPK-QG6QJA3-MPFYMSO-U56GTUK-NA2MIAW
2024-02-02 10:58:38 Relay listener (dynamic+https://relays.syncthing.net/endpoint) starting
2024-02-02 10:58:38 QUIC listener ([::]:22000) starting
2024-02-02 10:58:38 Using discovery mechanism: global discovery server https://discovery-v6.syncthing.net/v2/?nolookup&id=LYXKCHX-VI3NYZR-ALCJBHF-WMZYSPK-QG6QJA3-MPFYMSO-U56GTUK-NA2MIAW
2024-02-02 10:58:38 GUI and API listening on 127.0.0.1:8384
2024-02-02 10:58:38 ...
2024-02-02 10:58:38 Access the GUI via the following URL: https://127.0.0.1:8384/
2024-02-02 10:58:38 My name is "FP5"
2024-02-02 10:58:38 Device QPG5PJU-NWJ7XCK-RPAHGJT-GZYG2TU-6PKVORY-IWCXKAR-ADRNSKN-CHXX5AQ is "t480s" at [dynamic]
2024-02-02 10:58:38 Using discovery mechanism: IPv4 local broadcast discovery on port 21027
2024-02-02 10:58:38 Using discovery mechanism: IPv6 local multicast discovery on address [ff12::8384]:21027
2024-02-02 10:58:38 Listing network interfaces: route ip+net: netlinkrib: permission denied
2024-02-02 10:58:38 Detected 0 NAT services
2024-02-02 10:58:38 Ready to synchronize "Scans" (e5hti-b6pwm) (sendreceive)
2024-02-02 10:58:39 Ready to synchronize "FP5/Camera" (e7dq3-ro6ja) (sendreceive)
2024-02-02 10:58:39 Completed initial scan of sendreceive folder "Scans" (e5hti-b6pwm)
2024-02-02 10:58:39 Ready to synchronize "Documents/Music" (oeshx-vnjuo) (sendonly)
2024-02-02 10:58:39 Ready to synchronize "Calibre-library" (qr34r-blnj7) (receiveonly)
2024-02-02 10:58:39 Completed initial scan of receiveonly folder "Calibre-library" (qr34r-blnj7)
2024-02-02 10:58:41 Completed initial scan of sendreceive folder "FP5/Camera" (e7dq3-ro6ja)
2024-02-02 10:58:41 Completed initial scan of sendonly folder "Documents/Music" (oeshx-vnjuo)
2024-02-02 10:58:58 quic://0.0.0.0:22000 detected NAT type: Port restricted NAT
2024-02-02 10:58:58 quic://0.0.0.0:22000 resolved external address quic://217.159.161.200:22000 (via stun.syncthing.net:3478)
2024-02-02 10:59:34 Joined relay relay://83.146.237.228:22067

Open the web GUI in the app and post a screenshot of thd device IPs of t480s

Weird… all of a sudden the android connected with the linux through no fault of my own. No changes in config, no restarts of any services, just boom and connect and full sync. Let’s hope it stays like that…