Does AirVPN support compression?

tamikyle

OpenVPN allows for LZO and LZ4 compression -- do AirVPN's servers support any kind of compression?

zhang888

Compression is supported, but not recommended for all devices.

Note that most data that passes inside the tunnel is not compressible in any case, so the theoretical

gain you can benefit from using compression is very limited by what you are going to test.

Unless you are doing iperf tests with compressible data, such as /dev/zero, this is not going to benefit

you much, as most of the real-life traffic is not compressible from the beginning, such as encrypted

underlying protocols (when you use HTTPS websites) and so on.

This is based on the axiom that encrypted data is random. And random data can't be compressed.

A safer default would be turning it off, or at the best as 'adaptive'.

From the OpenVPN wiki:

With adaptive compression, OpenVPN will periodically sample the compression process to measure its efficiency. If the data being sent over the tunnel is

already compressed, the compression efficiency will be very low, triggering openvpn to disable compression for a period of time until the next re-sample test.

This was a more practical feature in the earlier days of the internet, when most traffic was counted and billed and data was mostly plain-text.

More about it here:

https://airvpn.org/topic/18418-openvpns-switches-for-performance-improvements/?p=44145