[SOLVED] As soon as my bandwidth gets saturated I can't establish/keep VPN co...

[Cyberturtle]

Hi there,

currently I have a problem. I recognized something yesterday when I was starting a huge download on my Xbox Series X. Suddenly my wife's and my laptop lost their VPN connections to our work and we haven't been able to work with our RDP connections reliably. Every now and then our connections timed out.

I already have setup FQ-CoDel like recommended by many howtos in the WWW. Bufferbloat tests show A or A+. After the connection drops occured I set up additional prio queues for TCP ack, DNS and of course the network address of our work. After that I reduced the bandwidth in the pipes as well. The shaper status shows that the rules are being used.

I can reproduce this issue by starting a huge download on any client in our home network. The Ubuntu Iso download is a good test for reproduction. As soon as I start it and the bandwidth gets saturated, the issue occurs. I need many tries to establish a VPN connection on my client. It seems as some packets are getting lost or so.

My hardware is:
VENEON P09B
Intel I-225V B3
Intel J4125 CPU
Crucial 16 GB RAM DDR4
Kingston SSD 256 GB

My provider is Deutsche Telekom with dual stack. PPPoE is being handled by OPNsense 23.1.7_3. I'm using a Speedport Smart 4 as modem. If I'm using a Fritzbox 4060 as test device, everythin is working fine. My line is synced with 179 Mbit/s down and 46,9 Mbit/s up. The pipes are configured with 160 Mbit/s down and 43 Mbit/s up. I also tried toggling ECN.

By the way a huge download don't affect watching Disney+ or Netflix. It seems to affect only our working VPN.

Sadly, I don't know what else I could try.

I'm so sad as I like OPNsense and all the stuff really much.

Thanks in advance,
Cyberturtle

[Supermule]

Thats normal. You are DDoS'ing yourself and the pipe cannot keep up. It builds a queue and eventually the connection dies.

You need to throttle the connection so vital traffic is kept alive.

[Cyberturtle]

Thanks for your immediate answer. Which connection should I throttle and how do I do this? I’m pretty new to OPNsense.

[Cyberturtle]

Hi there,
maybe I have found the issue. Today I tried pfSense. At first after initial setup it worked. Then I plugged everything back to the switch and boom heavy packet loss. My switch in the cabinet screwed up everything. After installing new firmware for it which fixes saturation problems and memory hogs the problem disappeared on my pfSense installation.
Tomorrow I’ll try recovering OPNsense and hope it’ll run with the fixed switch as good as today.
Will keep you updated.
Thanks a lot for helping.

[Cyberturtle]

Finally I can say it has been a faulty switch.