Asymmetrical OpenVPN speeds on symmetrical Gigabit service



  • I've been racking my brains over this for a while and finally decided that I'd gotten as far as I was going to be able to with Google-Fu and my own two remaining brain cells... and that letting go of my sense of pride and asking for help would be the wisest choice, so:

    I'm running pfSense on a dedicated box with an Intel Pentium CPU G4400 (3.30GHz), 8 GB of RAM, and an Intel PRO/1000 PT Dual Port Server Adapter card at home. My ISP is Sonic (I'm in the US), but the actual connection is through AT&T, so I like connecting to Sonic through their own OpenVPN server in order to maintain some semblance of privacy.

    Now, when I run a speed test from a desktop computer in my LAN without the OpenVPN connection, I pretty much get symmetrical speeds that are virtually 1 Gbps. Needless to say, I expected the speeds to be lower when running the OpenVPN connection, but what I don't get is the following: With OpenVPN, the download speed is around 350 Mbps and the upload speed is around 150 Mbps. I have no clue why this is happening, i.e., why they're asymmetrical. Anyone have any idea?

    Relevant details:

    Traffic shaping is completely disabled
    AES-NI is enabled
    Hardware Crypto is set to None
    NCP algorithms: AES-256-GCM and AES-128-GCM
    UDP Fast I/O is enabled
    Playing with the Send/Receive Buffer has not made much of a difference
    I've added the net.inet.ip.fastforwarding tunable and set it to 1

    I'll be more than happy to do any testing required, but I'll be honest and say that the testing stuff is pretty new to me, so please be patient if I ask dumb questions - I want to make sure I get you the information you need instead of wasting your time!


  • LAYER 8 Netgate

    Maybe the sonic server can only receive 150 but can send 350?



  • That... uuuuuhhh... would actually make a lot of sense. I'll go ahead and ask them, thanks!


Log in to reply