Site-to-Site OpenVPN compression slower than Viscosity client

  • Greetings all,

    I am running a test between my house and the data center using pfSense 2.1.5 and pfSense OpenVPN client vs Viscosity client (Mac version 1.5.3).

    I have two server instances of OpenVPN setup at the DC; one for my Viscosity client listening on port 1194 and the other for the pfSense site-to-site configuration listening on port 1195.  I have enabled LZO compression on both server configs (the server configs are almost 100% identical).  I have enabled LZO compression in my Viscosity config file as well as enabled LZO compression on my client OpenVPN config in pfSense.

    To test the compression speeds, I created a 100MB null test file on a remote server (dd if=/dev/zero of=file bs=1M count=100) and moved this to the web server's directory.  When I establish the OpenVPN connection with my Viscosity client, I get 12MB/sec download using the command, "curl -O".  When I establish the OpenVPN connection using pfSense as the client, I get 7MB/sec download using the same command.  During this time, the CPU on the client side hovers around 55% while the server side stays around 3%.

    I have tried various LZO options on both the OpenVPN client and server configs, but nothing has worked as well as the Viscosity client connection.  I looked over the Viscosity configuration file and made sure the same options were set in the pfSense configs.

    Any pointers?  I would expect both client connection types (Viscosity and pfSense) to give the same compression speeds…


  • Rebel Alliance Developer Netgate

    How many cores on the client firewall? Sitting at 55% sounds like two cores and one core is fully maxed out.

    Your PC probably has a faster CPU (and perhaps crypto acceleration), so it's not too surprising it handles more VPN traffic than the firewall alone in that case.

  • Thanks jump.

    Yep, that seems to be it.  I am running an ATOM Dual-Core 1.66GHz D510 CPU, and it can only muster about 7-8MB/sec with compression on the OpenVPN tunnel.  I can easily hit 10-11MB/sec using my Mac laptop (Quad-core i7).

    Appreciate the reply.

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