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    High download, but low upload bandwidth for gateway routing

    Scheduled Pinned Locked Moved Routing and Multi WAN
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    • D
      david97643
      last edited by david97643

      I'm routing traffic from single SIM cards via pfSense via a second EC2 gateway, but my upload speeds continuously converge to 0 mbit.

      I'm using an AWS pfSense instance as a NAT gateway for SIM card internet traffic. The internet traffic is routed to my AWS VPC via direct connect. All traffic is then routed to the pfSense instance. I'm routing traffic from the SIM to a gateway (different EC2) via a firewall rule (if source is X -> gateway Y).

      It all works (the internet-facing public IP of the SIM is that of the second EC2) but when performing speed tests, the upload bandwidth converges to 0Mbit (where the download bandwidth is quite good). When I use the pfSense to NAT traffic to the internet, upload speeds are way better. My guess is that there is some kind of mismatch, or congestion, but that seems unlikely as there is hardly any traffic going through the setup, let alone the 1Gb+ Mbit network performance of EC2's.

      I've tried:

      • Traffic shaping (including Bufferbloat tests)

      • MTU tweaking

      But these things don't seem to have the intended effect.

      Does anyone have an idea where to look? I'm out of options...

      Best regards,

      David

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      • D
        david97643
        last edited by

        overview.png

        I made a sketch to clarify

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