I'm trying do do a PPP serial tunnel between two RB devices. It somewhat works but I have some strange fenomenas.
First I seem to get a lots of junk traffic on the tunnel, I see that the lights of the serial connect is blinking extremly fast and until connection seem to reset and calms down a bit and then it start talking more and more and squence repeats itself again. The only traffic that is sent over the tunnel is a modbus TCP (port 502) from host 172.16.11.34 on one side to .11.36 on the other side of the PPP tunnel.
When I do a packet capture on the ppp-in interface I don't even see the request packet from .11.34 to .11.36 but I do see the response from .11.36 to .11.34 now and then so that means the .11.36 sometimes gets a request packets even if that isn't visible in the packet dump. Very strange. I wonder if a PPP interface packet capture bug is part of my problem? It records lots of "bogus" packets where IP version IP version is set to 0 (should be 4 as wireshark sais) and IP addresses looks completely wrong. See image for a short example. A full 4 second capture is attach in zip file.
Can someone help me explain this?
PPP server is setup like this (tunneled, not routed):
> export hide-sensitive (PPP parts)
set *0 bridge=bridge1 local-address=126.96.36.199 remote-address=188.8.131.52 use-compression=yes
add disabled=no name=ppp-in1 null-modem=yes port=serial0 ring-count=0
model = 450G