VPN server: high cpu % utilization with 0 active sessions

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neskire
Posts: 4
Joined: Sat Apr 12, 2014 10:55 am

VPN server: high cpu % utilization with 0 active sessions

Post by neskire » Sat Apr 12, 2014 11:30 am

Hello,
I am currently running VPN server on windows, and i find that the VPN server is using CPU % based on the amount of traffic is going through the server (i.e. file transfers, browsing, torrents).
I want to point out that the vpn-server is only running, it currently has no open sessions, thus i don't see why it listens and utilize so much CPU, when it has no tasks to fulfill?.

I can understand that CPU usage goes up whenever a client is connected, and that CPU usage is linked to how the encryption is done and how much bandwidth the client is using through the vpn tunnel.

Point in case is: If I'm transferring with 100mbits from SMB shares, the VPN cpu usage is about 25%. I can manually click VPN-server to "Offline" and the cpu usage drops to 0.

[attachment=0]softether-vpn.jpg[/attachment]

1. Windows 8.1 Pro
==================================

2. "ipconfig /all" (Windows)

C:\Users\neskire>ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : microserver
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : zyxel.com

Ethernet adapter Ethernet:

Connection-specific DNS Suffix . : zyxel.com
Description . . . . . . . . . . . : Broadcom NetXtreme Gigabit Ethernet
Physical Address. . . . . . . . . : C8-CB-B8-CA-F0-0A
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::bc39:4c49:b4a7:4a13%3(Preferred)
IPv4 Address. . . . . . . . . . . : 10.0.0.100(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : 10. april 2014 07:47:26
Lease Expires . . . . . . . . . . : 12. april 2014 23:44:42
Default Gateway . . . . . . . . . : 10.0.0.1
DHCP Server . . . . . . . . . . . : 10.0.0.1
DHCPv6 IAID . . . . . . . . . . . : 63491000
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-1A-D6-99-56-C8-CB-B8-CA-F0-0A

DNS Servers . . . . . . . . . . . : 10.0.0.1
8.8.8.8
8.8.4.4
NetBIOS over Tcpip. . . . . . . . : Enabled

Tunnel adapter isatap.zyxel.com:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . : zyxel.com
Description . . . . . . . . . . . : Microsoft ISATAP Adapter
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Local Area Connection* 3:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
IPv6 Address. . . . . . . . . . . : 2001:0:5ef5:79fd:30f3:33b3:7d1d:6295(Pref
erred)
Link-local IPv6 Address . . . . . : fe80::30f3:33b3:7d1d:6295%5(Preferred)
Default Gateway . . . . . . . . . : ::
DHCPv6 IAID . . . . . . . . . . . : 134217728
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-1A-D6-99-56-C8-CB-B8-CA-F0-0A

NetBIOS over Tcpip. . . . . . . . : Disabled[/code]
==================================

3. "systeminfo" (Windows)
C:\Users\neskire>systeminfo

Host Name: MICROSERVER
OS Name: Microsoft Windows 8.1 Pro
OS Version: 6.3.9600 N/A Build 9600
OS Manufacturer: Microsoft Corporation
OS Configuration: Standalone Workstation
OS Build Type: Multiprocessor Free
Registered Owner: neskire
Registered Organization:
Product ID: 00261-50000-00000-AA989
Original Install Date: 09-04-2014, 08:05:59
System Boot Time: 10-04-2014, 07:47:08
System Manufacturer: HP
System Model: ProLiant MicroServer
System Type: x64-based PC
Processor(s): 1 Processor(s) Installed.
[01]: AMD64 Family 16 Model 6 Stepping 3 AuthenticAMD
~2200 Mhz
BIOS Version: HP O41 , 01-10-2013
Windows Directory: C:\Windows
System Directory: C:\Windows\system32
Boot Device: \Device\HarddiskVolume1
System Locale: da;Dansk
Input Locale: da;Dansk
Time Zone: (UTC+01:00) København, Stockholm, Oslo, Madrid, Paris

Total Physical Memory: 2.015 MB
Available Physical Memory: 833 MB
Virtual Memory: Max Size: 4.465 MB
Virtual Memory: Available: 2.147 MB
Virtual Memory: In Use: 2.318 MB
Page File Location(s): C:\pagefile.sys
Domain: WORKGROUP
Logon Server: \\MICROSERVER
Hotfix(s): 58 Hotfix(s) Installed.
....[HOT FIX ECHO REMOVED]....

Network Card(s): 1 NIC(s) Installed.
[01]: Broadcom NetXtreme Gigabit Ethernet
Connection Name: Ethernet
DHCP Enabled: Yes
DHCP Server: 10.0.0.1
IP address(es)
[01]: 10.0.0.100
[02]: fe80::bc39:4c49:b4a7:4a13
Hyper-V Requirements: VM Monitor Mode Extensions: Yes
Virtualization Enabled In Firmware: Yes
Second Level Address Translation: Yes
Data Execution Prevention Available: Yes

==================================

4. The build number of SoftEther VPN
build 9437
==================================

5. Which SoftEther VPN component are you using?
SERVER
==================================

6. Whether or not there is a NAT or Firewall between your VPN server and the Internet.
There is a NAT, however i am only doing local testing as of yet so opening nat ports is irrelevant atm.
==================================

7. Are you using SecureNAT?
No, i am using Local Bridged Mode
==================================

8. Your current vpn_server.config or vpn_bridge.config file should be attached on the post.
vpn_server.config : https://www.dropbox.com/s/6y84ttpfymggl ... config.zip
Settings point in time when screenshots were taken.


ps. Any other VPN server software i have had installed on previous machines have had 0-1% cpu usage when 0 clients were connected, Even if i was transferring large amounts of data off or onto the server. However did i connect a client, and transfer these same data through the vpn tunnel, of course cpu usage rose to 100%.
You do not have the required permissions to view the files attached to this post.

thisjun
Posts: 2150
Joined: Mon Feb 24, 2014 11:03 am

Re: VPN server: high cpu % utilization with 0 active session

Post by thisjun » Tue Apr 15, 2014 7:55 am

Your server receive a lot of packet.
Is there many PCs in your LAN?

neskire
Posts: 4
Joined: Sat Apr 12, 2014 10:55 am

Re: VPN server: high cpu % utilization with 0 active session

Post by neskire » Wed Apr 16, 2014 11:23 am

It's receiving a lot of packages because i'm transferring with 5 mb/s over SMB.
That shouldnt affect the vpn the sligtest since its not connecting over vpn. Granted the VPN server is active, but isn't handling any packages, so why should the CPU spike so high?
I can tolerate that it has to listen on various ports and pick of a few packages, but to act exactly like its running the whole show, that doesnt seem right.

The "Softether VPN server.exe" CPU usage is equally high whether or not im transfering 5mb/s over VPN or 5mb/s locally without connecting through the VPN.

Is there any settings to eliminate this behaviour or should i change to OpenVPN ?

mesa57
Posts: 153
Joined: Fri Oct 11, 2013 4:00 pm
Location: Netherlands

Re: VPN server: high cpu % utilization with 0 active session

Post by mesa57 » Tue Oct 28, 2014 9:00 pm

*bump*
Same problem here on a raspberry with smb.

thisjun
Posts: 2150
Joined: Mon Feb 24, 2014 11:03 am

Re: VPN server: high cpu % utilization with 0 active session

Post by thisjun » Thu Nov 06, 2014 7:49 am

Classification of packets on usermode is heavy task.
How about using bridge function of OS?

neskire
Posts: 4
Joined: Sat Apr 12, 2014 10:55 am

Re: VPN server: high cpu % utilization with 0 active session

Post by neskire » Thu Nov 06, 2014 10:55 am

I never thought of that. Would I need to disable ip table and virtual dhcp server for that, and then just mark both lan and vpn-lan and bridge then with windows context menu?

mesa57
Posts: 153
Joined: Fri Oct 11, 2013 4:00 pm
Location: Netherlands

Re: VPN server: high cpu % utilization with 0 active session

Post by mesa57 » Thu Nov 06, 2014 11:34 am

In my configuration the softether server is bridged with eth0. I do not use Securenat.
How should I use the OS bridge function ?

BitingChaos
Posts: 4
Joined: Tue Nov 11, 2014 3:49 am

Re: VPN server: high cpu % utilization with 0 active session

Post by BitingChaos » Tue Nov 11, 2014 6:31 am

Add me to the list that this impacts.

Zero users, yet "vpnserver_x64.exe" takes up a ton of CPU. Up to 34% CPU usage.

Pentium D (Dual-Core) @ 2.8 GHz, 4GB RAM, Server 2008 R2 (x64).

neskire
Posts: 4
Joined: Sat Apr 12, 2014 10:55 am

Re: VPN server: high cpu % utilization with 0 active session

Post by neskire » Tue Nov 11, 2014 7:23 am

Yeah am i running clean setup, no securenat, only the virtual bridge. Can't use OS own bridge setting since Softether doesnt create a new virtual nat interface that windows can interact with.

Since we know this problem is there and persist. Lets put our brains to work and make a work-around. Any other ideas?

thisjun
Posts: 2150
Joined: Mon Feb 24, 2014 11:03 am

Re: VPN server: high cpu % utilization with 0 active session

Post by thisjun » Tue Nov 25, 2014 6:16 am

Did you try a tap mode localbridge?

thisjun
Posts: 2150
Joined: Mon Feb 24, 2014 11:03 am

Re: VPN server: high cpu % utilization with 0 active session

Post by thisjun » Thu Apr 30, 2015 8:06 am

mulltone wrote:
> I have the same problem.
> My Windows 2008 R2 Server is VPN server and File Server so when i copy large files
> over network the CPU goes up to 35 %.
>
> Have someone found a solution for the problem ?

It seems normal situation.
?????

serhan
Posts: 2
Joined: Sat Oct 10, 2015 10:14 pm

Re: VPN server: high cpu % utilization with 0 active session

Post by serhan » Sat Oct 17, 2015 5:20 pm

This is still the case with version 4.19. If real ethernet card is utilized, softethernet card (vpnserver.exe) starts consuming serious cpu time. I think this is the softethers nature by its design. So not much to expect as a solution.

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