Softether performance on virtual server

Post your questions about SoftEther VPN software here. Please answer questions if you can afford.
Post Reply
ivica.glavocic
Posts: 5
Joined: Thu Dec 04, 2014 7:08 am

Softether performance on virtual server

Post by ivica.glavocic » Wed Jan 10, 2018 2:46 pm

Softether installed on old P4 physical CentOS6 x64 machine with 2 interfaces (LAN + WAN) works perfectly on 40/10 Mbps link. SSTP throughput is download 40 Mbps, upload 10 Mbps.

Same Softhether server installed on same OS and same link as XEN virtual machine has limited throughput of 8 Mbps in download and same for upload.

Softether is bridged to eth0 interface. Only difference is log entry on virtualized server:
"SID-LOCALBRIDGE-1": The physical Ethernet interface "eth0" has an MTU value set to 1514. It is necessary to send and receive an Ethernet packet which has 1835 bytes. However, changing the MTU to 1835 failed. This physical Ethernet interface or device driver might be unable to process an Ethernet packet which has more 1,514 bytes (payload size: 1,500 bytes). In such case, the larger tagged-VLAN packets than 1,514 bytes cannot be transmitted. You should replace the current physical Ethernet adapter to another which supports Jumbo Frames. You can also try to update the device driver. Another possible method is to enable Jumbo Frames on the operating system or device driver settings.

Interfaces on physical machine are:
eth0: Intel(R) PRO/1000 Network Connection
eth1: VIA Rhine II

Interfaces on virtual machine are (both eth0 and eth1)
xen_netfront: Initialising Xen virtual ethernet driver

What is the problem with throughput on virtual Softether? How can I make virtualized server to be as fast as physical machine?

Thanks, regards
Ivica

ivica.glavocic
Posts: 5
Joined: Thu Dec 04, 2014 7:08 am

Re: Softether performance on virtual server

Post by ivica.glavocic » Fri Jan 12, 2018 4:30 pm

No replies so I will reply to myself. All performance issues are solved when I bridged Softether with tap interface, and then bridged tap with eth0 using standard Linux br0 bridge. I have full bandwidth now and also I can access Softether itself when connected with VPN (SSTP, OpenVPN, L2TP/IPSEC) from Internet. Solution for CentOS is easy, no additional scripts to enable bridge after boot, just usual config in /etc/sysconfig/network-scripts/ifcfg-*.
I am suprised that this is not official solution from Softether team on Linux platform.

Post Reply