Hey there,

I'm trying to connect my android client to a wireguard server. This worked
absolutly fine in the past.

However now the client isn't initiating a handshake. I've tried it on my
wireless and cellular network. It doesn't work with on that android device.
However it works absolutly fine on every other device in my network
(Raspberry, Linux computers etc.).

So I've done some debugging. When sniffing the traffic on my router using
tcpdump there is absolutly no connection to my server and my server doesn't
receive anything to.

Then I looked at the logcat of wireguard and saw that it stopped after
"Device started". On another device from a friend of mine it continues with
the handshake.

Here's the log of the non working device:
>>>10-04 20:08:46.663 17087 21706 D WireGuard/GoBackend: Changing tunnel
XXX to state UP
10-04 20:08:46.663 17087 21706 I WireGuard/GoBackend: Bringing tunnel up
10-04 20:08:46.687 17087 21706 D WireGuard/GoBackend: Go backend
v0.0.20180613
10-04 20:08:46.687 17087 21706 D WireGuard/GoBackend/XXX: Debug log enabled
10-04 20:08:46.687 17087 21706 I WireGuard/GoBackend/XXX: Attaching to
interface tun0
10-04 20:08:46.688 17087 17132 D WireGuard/GoBackend/XXX: Routine:
decryption worker - started
10-04 20:08:46.688 17087 17132 D WireGuard/GoBackend/XXX: Routine:
encryption worker - started
10-04 20:08:46.688 17087 17132 D WireGuard/GoBackend/XXX: Routine: event
worker - started
10-04 20:08:46.688 17087 17116 D WireGuard/GoBackend/XXX: Routine:
decryption worker - started
10-04 20:08:46.688 17087 17116 D WireGuard/GoBackend/XXX: Routine:
handshake worker - started
10-04 20:08:46.688 17087 17132 D WireGuard/GoBackend/XXX: Routine:
decryption worker - started
10-04 20:08:46.688 17087 17132 D WireGuard/GoBackend/XXX: Routine:
encryption worker - started
10-04 20:08:46.688 17087 17116 D WireGuard/GoBackend/XXX: Routine:
decryption worker - started
10-04 20:08:46.688 17087 17116 D WireGuard/GoBackend/XXX: Routine:
decryption worker - started
10-04 20:08:46.688 17087 17116 D WireGuard/GoBackend/XXX: Routine:
handshake worker - started
10-04 20:08:46.688 17087 17132 D WireGuard/GoBackend/XXX: Routine:
decryption worker - started
10-04 20:08:46.688 17087 17132 D WireGuard/GoBackend/XXX: Routine:
encryption worker - started
10-04 20:08:46.688 17087 17132 D WireGuard/GoBackend/XXX: Routine:
handshake worker - started
10-04 20:08:46.688 17087 17116 D WireGuard/GoBackend/XXX: Routine:
encryption worker - started
10-04 20:08:46.688 17087 17116 D WireGuard/GoBackend/XXX: Routine:
handshake worker - started
10-04 20:08:46.688 17087 17116 D WireGuard/GoBackend/XXX: Routine:
encryption worker - started
10-04 20:08:46.689 17087 17116 D WireGuard/GoBackend/XXX: Routine:
handshake worker - started
10-04 20:08:46.689 17087 17116 D WireGuard/GoBackend/XXX: Routine:
encryption worker - started
10-04 20:08:46.689 17087 17116 D WireGuard/GoBackend/XXX: Routine:
decryption worker - started
10-04 20:08:46.689 17087 17116 D WireGuard/GoBackend/XXX: Routine:
handshake worker - started
10-04 20:08:46.689 17087 17116 D WireGuard/GoBackend/XXX: Routine:
encryption worker - started
10-04 20:08:46.689 17087 17116 D WireGuard/GoBackend/XXX: Routine:
handshake worker - started
10-04 20:08:46.689 17087 17116 D WireGuard/GoBackend/XXX: Routine:
encryption worker - started
10-04 20:08:46.689 17087 17116 D WireGuard/GoBackend/XXX: Routine:
handshake worker - started
10-04 20:08:46.689 17087 17116 D WireGuard/GoBackend/XXX: Routine:
decryption worker - started
10-04 20:08:46.689 17087 17116 D WireGuard/GoBackend/XXX: Routine: TUN
reader - started
10-04 20:08:46.690 17087 21706 D WireGuard/GoBackend/XXX: Interface has MTU
1280
10-04 20:08:46.690 17087 21706 D WireGuard/GoBackend/XXX: UAPI: Removing
all peers
10-04 20:08:46.690 17087 21706 D WireGuard/GoBackend/XXX: UAPI: Updating
private key
10-04 20:08:46.694 17087 21706 D WireGuard/GoBackend/XXX: UAPI: Transition
to peer configuration
10-04 20:08:46.699 17087 21706 D WireGuard/GoBackend/XXX: peer(lrQt5XFs)
- UAPI: Created
10-04 20:08:46.699 17087 21706 D WireGuard/GoBackend/XXX: peer(lrQt5XFs)
- UAPI: Updating endpoint
10-04 20:08:46.700 17087 21706 D WireGuard/GoBackend/XXX: peer(lrQt5XFs)
- UAPI: Updating persistent keepalive interva
10-04 20:08:46.701 17087 21706 D WireGuard/GoBackend/XXX: peer(lrQt5XFs)
- UAPI: Adding allowedip
10-04 20:08:46.703 17087 17108 D WireGuard/GoBackend/XXX: Routine: receive
incoming IPv6 - starting
10-04 20:08:46.703 17087 20915 D WireGuard/GoBackend/XXX: Routine: receive
incoming IPv4 - starting
10-04 20:08:46.703 17087 21706 D WireGuard/GoBackend/XXX: UDP bind has been
updated
10-04 20:08:46.703 17087 21706 D WireGuard/GoBackend/XXX: peer(lrQt5XFs)
- Starting...
10-04 20:08:46.704 17087 17135 D WireGuard/GoBackend/XXX: peer(lrQt5XFs)
- Routine: sequential receiver - started
10-04 20:08:46.704 17087 17108 D WireGuard/GoBackend/XXX: peer(lrQt5XFs)
- Routine: nonce worker - started
10-04 20:08:46.704 17087 17135 D WireGuard/GoBackend/XXX: peer(lrQt5XFs)
- Routine: sequential sender - started
10-04 20:08:46.704 17087 21706 I WireGuard/GoBackend/XXX: Device started
'
And here's the log on the working device:
10-04 20:14:13.349 13605 13622 D WireGuard/GoBackend: Changing tunnel
vserver to state UP
10-04 20:14:13.349 13605 13622 I WireGuard/GoBackend: Bringing tunnel up
10-04 20:14:13.350 13605 13622 D WireGuard/GoBackend: Requesting to start
VpnService
10-04 20:14:13.518 13605 13622 D WireGuard/GoBackend: Go backend
v0.0.20180613
10-04 20:14:13.519 13605 13622 D WireGuard/GoBackend/vserver: Debug log
enabled
10-04 20:14:13.520 13605 13622 I WireGuard/GoBackend/vserver: Attaching to
interface tun0
10-04 20:14:13.545 13605 13631 D WireGuard/GoBackend/vserver: Routine:
event worker - started
10-04 20:14:13.545 13605 13631 D WireGuard/GoBackend/vserver: Routine:
encryption worker - started
10-04 20:14:13.545 13605 13631 D WireGuard/GoBackend/vserver: Routine:
decryption worker - started
10-04 20:14:13.545 13605 13631 D WireGuard/GoBackend/vserver: Routine:
handshake worker - started
10-04 20:14:13.545 13605 13631 D WireGuard/GoBackend/vserver: Routine:
handshake worker - started
10-04 20:14:13.545 13605 13631 D WireGuard/GoBackend/vserver: Routine:
encryption worker - started
10-04 20:14:13.545 13605 13631 D WireGuard/GoBackend/vserver: Routine:
decryption worker - started
10-04 20:14:13.545 13605 13623 D WireGuard/GoBackend/vserver: Routine:
decryption worker - started
10-04 20:14:13.545 13605 13631 D WireGuard/GoBackend/vserver: Routine:
handshake worker - started
10-04 20:14:13.545 13605 13631 D WireGuard/GoBackend/vserver: Routine:
encryption worker - started
10-04 20:14:13.545 13605 13631 D WireGuard/GoBackend/vserver: Routine:
handshake worker - started
10-04 20:14:13.545 13605 13623 D WireGuard/GoBackend/vserver: Routine:
encryption worker - started
10-04 20:14:13.545 13605 13623 D WireGuard/GoBackend/vserver: Routine:
handshake worker - started
10-04 20:14:13.545 13605 13623 D WireGuard/GoBackend/vserver: Routine:
decryption worker - started
10-04 20:14:13.546 13605 13631 D WireGuard/GoBackend/vserver: Routine: TUN
reader - started
10-04 20:14:13.546 13605 13650 D WireGuard/GoBackend/vserver: Routine:
encryption worker - started
10-04 20:14:13.546 13605 13650 D WireGuard/GoBackend/vserver: Routine:
encryption worker - started
10-04 20:14:13.546 13605 13623 D WireGuard/GoBackend/vserver: Routine:
decryption worker - started
10-04 20:14:13.546 13605 13650 D WireGuard/GoBackend/vserver: Routine:
handshake worker - started
10-04 20:14:13.546 13605 13650 D WireGuard/GoBackend/vserver: Routine:
handshake worker - started
10-04 20:14:13.546 13605 13650 D WireGuard/GoBackend/vserver: Routine:
decryption worker - started
10-04 20:14:13.546 13605 13650 D WireGuard/GoBackend/vserver: Routine:
encryption worker - started
10-04 20:14:13.546 13605 13650 D WireGuard/GoBackend/vserver: Routine:
encryption worker - started
10-04 20:14:13.546 13605 13650 D WireGuard/GoBackend/vserver: Routine:
handshake worker - started
10-04 20:14:13.546 13605 13655 D WireGuard/GoBackend/vserver: Routine:
decryption worker - started
10-04 20:14:13.547 13605 13651 D WireGuard/GoBackend/vserver: Routine:
decryption worker - started
10-04 20:14:13.547 13605 13622 D WireGuard/GoBackend/vserver: Interface has
MTU 1280
10-04 20:14:13.548 13605 13622 D WireGuard/GoBackend/vserver: UAPI:
Removing all peers
10-04 20:14:13.548 13605 13622 D WireGuard/GoBackend/vserver: UAPI:
Updating private key
10-04 20:14:13.549 13605 13622 D WireGuard/GoBackend/vserver: UAPI:
Transition to peer configuration
10-04 20:14:13.550 13605 13622 D WireGuard/GoBackend/vserver:
peer(fJY3fFm0) - UAPI: Created
10-04 20:14:13.550 13605 13622 D WireGuard/GoBackend/vserver:
peer(fJY3fFm0) - UAPI: Updating endpoint
10-04 20:14:13.550 13605 13622 D WireGuard/GoBackend/vserver:
peer(fJY3fFm0) - UAPI: Updating persistent keepalive interva
10-04 20:14:13.550 13605 13622 D WireGuard/GoBackend/vserver:
peer(fJY3fFm0) - UAPI: Adding allowedip
10-04 20:14:13.550 13605 13622 D WireGuard/GoBackend/vserver:
peer(fJY3fFm0) - UAPI: Adding allowedip
10-04 20:14:13.556 13605 13651 D WireGuard/GoBackend/vserver: Routine:
receive incoming IPv6 - starting
10-04 20:14:13.557 13605 13655 D WireGuard/GoBackend/vserver: Routine:
receive incoming IPv4 - starting
10-04 20:14:13.558 13605 13622 D WireGuard/GoBackend/vserver: UDP bind has
been updated
10-04 20:14:13.558 13605 13622 D WireGuard/GoBackend/vserver:
peer(fJY3fFm0) - Starting...
10-04 20:14:13.558 13605 13630 D WireGuard/GoBackend/vserver:
peer(fJY3fFm0) - Routine: nonce worker - started
10-04 20:14:13.558 13605 13630 D WireGuard/GoBackend/vserver:
peer(fJY3fFm0) - Routine: sequential sender - started
10-04 20:14:13.558 13605 13655 D WireGuard/GoBackend/vserver:
peer(fJY3fFm0) - Routine: sequential receiver - started
10-04 20:14:13.558 13605 13622 I WireGuard/GoBackend/vserver: Device started
10-04 20:14:13.801 13605 13655 D WireGuard/GoBackend/vserver:
peer(fJY3fFm0) - Sending handshake initiation
10-04 20:14:13.804 13605 13655 D WireGuard/GoBackend/vserver:
peer(fJY3fFm0) - Awaiting keypair
10-04 20:14:13.822 13605 13623 D WireGuard/GoBackend/vserver:
peer(fJY3fFm0) - Received handshake response
10-04 20:14:13.822 13605 13623 D WireGuard/GoBackend/vserver:
peer(fJY3fFm0) - Obtained awaited keypair

And here's the config:
[Interface]
Address = fd00:2:1::5/64
PrivateKey = YAXZKLpq+XXXX

[Peer]
AllowedIPs = fd00::/16
Endpoint = XXX.de:51820
PersistentKeepalive = 25
PublicKey = lrQtqqXosiux8XXXX

Do you've any idea why this happen? If you need further information for
debugging let me know!.

Thanks in advance
Sören