Proxmox GRE tunnel permanently lost connection after 1 week uptime

[KingArthur98]

Hi Folks,

I have a serious problem; i'm using an external VPS with an (unbound) failover ip to make a GRE-TAP tunnel to my Proxmox server at Hetzner.
I have one node with one windows guest. The tunnel worked absolutely perfect for a week, but then suddenly it quit working.

I thought it was on the VPS side; reinstalled that completely to be sure but the tunnel just doesnt work anymore.
I can still ping through it from the Hetzner side; and with TCPdump I see the traffic sending and reaching the Hetzner server but the Windows guest can't reach the internet anymore

I thought maybe this was related but I am not sure:
https://github.com/virtio-win/kvm-guest-drivers-windows/issues/416

VPS:

ip link add tunnel0 type gretap remote 46.4.XX.XX local 5.196.XXX.XXX
ip link set up tunnel0

ip route add 10.10.10.0/24 dev tunnel0
ip addr add 10.10.10.2/24 dev tunnel0

arp -s 137.74.XX.XXX 02:00:00:XX:XX:XX -i eth0 pub
ip route add 137.74.XX.XXX/32 dev tunnel0

Proxmox:

ip link add tunnel1 type gretap remote 5.196.XXX.XXX local 46.4.XX.XX
ip link set up tunnel1

ip route add 10.10.10.0/24 dev tunnel1

brctl addif vmbr1 tunnel1
ip addr add 10.10.10.1/24 dev vmbr1

Proxmox /interfaces:

# network interface settings; autogenerated
# Please do NOT modify this file directly, unless you know what
# you're doing.
#
# If you want to manage parts of the network configuration manually,
# please utilize the 'source' or 'source-directory' directives to do
# so.
# PVE will preserve these directives, but will NOT read its network
# configuration from sourced files, so do not attempt to move any of
# the PVE managed interfaces into external files!

source /etc/network/interfaces.d/*

auto lo
iface lo inet loopback

iface lo inet6 loopback

auto eno1
iface eno1 inet static
        address  46.4.XX.XX
        netmask  255.255.255.255
        gateway  46.4.XX.X
        up route add -net 46.4.XX.X netmask 255.255.255.192 gw 46.4.XX.X dev eno1

iface eno1 inet6 static
        address  2a01:4f8:221:XXXX:X
        netmask  64
        gateway  fXXX::1

auto vmbr1
iface vmbr1 inet manual
        bridge-ports none
        bridge-stp off
        bridge-fd 0

Is there a bug with the GRETAP?
I am very in-experienced with networking stuff so I have no idea what to look for.

Greetings,
Merlijn

 

[KingArthur98]

Wireshark in windows