Teltonika routers (OpenWRT) connection type relayed

[Silex]

Hello,

I'm using self hosted netbird and it works great.

My peers have P2P (direct) connection, e.g between laptops/phones, no problem.

But my Teltonika routers are always in "Relayed" mode, they get internet through 4G/5G with a SIM card.

Here's some debug logs:

netbird.debug.1078192187.zip

What is weird is that the routers have direct connexion between themselves, but none of them has direct connexion with "normal peers" (PC, phones over wifi) with classic internet.

I installed & enabled an UPNP package on the router but that did not change anything.

I plan to use netbird for ~200 of these 4G/5G routers, and probably ~100 normal machines.

I'm a bit afraid that 200 relayed+ devices will create problems on the server, even tho for the moment it works great even in relayed mode (is there some documentation about scaling?). What can I try to improve connectivity?

[Silex]

Hello,

I discovered the issue is only between windows clients and linux routers.

When the client is installed on a linux computer, there's P2P connection with the routers.

On windows I noticed fragmentation does not work:

PS C:\Users\Philippe\Downloads> ping -l 1252 rut241-2097273190ac.netbird.stvs

Pinging router.netbird.selfhosted [100.70.214.129] with 1252 bytes of data:
Reply from 100.70.214.129: bytes=1252 time=72ms TTL=64
Reply from 100.70.214.129: bytes=1252 time=119ms TTL=64

PS C:\Users\Philippe\Downloads> ping -l 1253 rut241-2097273190ac.netbird.stvs

Pinging router.netbird.selfhosted [100.70.214.129] with 1253 bytes of data:
Request timed out.
Request timed out.

1253 + 28 is 1281 which is netbird MTU.

On linux there's not this problem:

root@someserver ~ ping -s 5000 router.netbird.selfhosted
PING router.netbird.selfhosted (100.70.214.129) 5000(5028) bytes of data.
5008 bytes from router.netbird.selfhosted (100.70.214.129): icmp_seq=1 ttl=64 time=120 ms
5008 bytes from router.netbird.selfhosteds (100.70.214.129): icmp_seq=2 ttl=64 time=91.9 ms

[Silex]

Hum, actually it's even more weird than that.

A: windows client (me)
B: linux machine
C: linux router

A <-- P2P --> B
B <-- P2P --> C
A <-- RELAYED --> C

I'll try to investiguate my client logs.