Performance issues with Softether but not with SSH tunnel

[iahmed]

Hello

I have Softether running on a server. If I create an SSH tunnel to the server, I can saturate both my local connection and the server connection (200 mbit+). When I connect using using SSTP, OpenVPN or L2TP/IPSec, I get very slow speeds.

When using L2TP/IPsec, Softether consumes no more than 10% of CPU giving 0.5 mbit connection. Many websites don't seem to load under this mode. For example, when loading the speedtest.net site, it kept indicating that it was trying to load resources such as javascript or stylesheets but if you open those resources in a new tab, they load instantly. Even when you refresh the speedtest page it still doesn't load.

When using SSTP, Softether uses around 60% of the CPU and gives varying speeds between 90 and 120mbit.

My server is running Ubuntu 14.04. We first installed Incredible PBX and then Softether. I have attached iptable, process list and the vpnserver config. Is it possible to get better performance by changing the configuration? Unfortunately upgrading the server isn't an option.

[thisjun]

Is there any error log in the server log?

[iahmed]

thisjun wrote:
> Is there any error log in the server log?

Thank you for you reply. Unfortunately, there are no errors in the log.

[thisjun]

Is there any suspicious traffic in the session? For example, traffic is larger than expected.
If same packets appear in packet log repeatedly, loop may be formed.