Suggestions for a bandwidth issue.

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Butterlord
OpenVpn Newbie
Posts: 1
Joined: Fri Jun 11, 2021 4:33 pm

Suggestions for a bandwidth issue.

Post by Butterlord » Fri Jun 11, 2021 5:09 pm

Hi,

I am helpless and look for advice.

I have a setup with two freebsd boxes. BOX (A) is the OpenVPN Server, BOX (B) the OpenVPN Client. Behind BOX A are two Windows 2019 Server. Behind BOX B are Centos 8 server. Centos & Windows should exchange data through OpenVPN.

Both BOX have a Xeon E3-1230 v3 @ 3.30GHz and enabled HW crypto but i assumes its not used.
Bandwith betwen both boxes is a symetrical 1Gbit/s connection through public internet.
Lines are professional, not end user with filtering or traffic shaping.
Everything works and iperf confirmed the connection speed without OpenVPN.

But there is unexepected low bandwidth in one direction.
Server -> Client 250 - 270Mbits .. which is kind of what i expected.
Client -> Server 17,7Mbits. I am that precise because that is how iperf looks:

Code: Select all

Connecting to host 192.168.1.240, port 5201
[  4] local 172.16.220.70 port 37189 connected to 192.168.1.240 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec  30.4 MBytes   255 Mbits/sec
[  4]   1.00-2.00   sec  31.2 MBytes   262 Mbits/sec
[  4]   2.00-3.00   sec  31.8 MBytes   266 Mbits/sec
[  4]   3.00-4.00   sec  31.5 MBytes   264 Mbits/sec
[  4]   4.00-5.00   sec  31.8 MBytes   266 Mbits/sec
(...)
This is vice versa:

Code: Select all

Connecting to host 172.16.220.70, port 5201
[  5] local 192.168.1.240 port 55676 connected to 172.16.220.70 port 5201
[ ID] Interval           Transfer     Bandwidth
[  5]   0.00-1.00   sec  3.68 MBytes  30.8 Mbits/sec 
[  5]   1.00-2.00   sec  1.64 MBytes  13.8 Mbits/sec  
[  5]   2.00-3.00   sec  2.11 MBytes  17.7 Mbits/sec      
[  5]   3.00-4.00   sec  2.11 MBytes  17.7 Mbits/sec      
[  5]   4.00-5.00   sec  2.11 MBytes  17.7 Mbits/sec      
[  5]   5.00-6.00   sec  2.11 MBytes  17.7 Mbits/sec 
[  5]   6.00-7.00   sec  2.11 MBytes  17.7 Mbits/sec       
[  5]   7.00-8.00   sec  2.11 MBytes  17.7 Mbits/sec      
[  5]   8.00-9.00   sec  2.11 MBytes  17.7 Mbits/sec       
[  5]   9.00-10.00  sec  2.11 MBytes  17.7 Mbits/sec       
Freebsd shows CPU around 3% when sending. NICs are at 1000Base-T. No Errors on the NICs. UDP. There is no traffice shaper anywhere. I tried some MTUs, fast-io and sndbuf setups just to verify things and see small effects on the fast side. Absolutly nothing happens on the slow connection. I tried a different UDP Port, didnt change. The configuration is minimal, Netgate-ish. Slow remains extremly constant at 17.7 Mbits, first a burst, then reduce, then 17.7 Mbits. When simultaneously Up/Downloading (iperf bidrectional) fast remains stable (1Mbits-ish difference, but thats noise of public internet). Slow connection however gets even more unsteady:

Code: Select all

[  5] local 192.168.1.240 port 48692 connected to 172.16.220.70 port 5201
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec  3.71 MBytes  31.1 Mbits/sec       
[  5]   1.00-2.00   sec  1.76 MBytes  14.8 Mbits/sec       
[  5]   2.00-3.00   sec  2.29 MBytes  19.2 Mbits/sec    
[  5]   3.00-4.00   sec  1.58 MBytes  13.3 Mbits/sec     
[  5]   4.00-5.00   sec  1.58 MBytes  13.3 Mbits/sec   
[  5]   5.00-6.00   sec  1.58 MBytes  13.3 Mbits/sec      
[  5]   6.00-7.00   sec  1.41 MBytes  11.8 Mbits/sec    
[  5]   7.00-8.00   sec  1.41 MBytes  11.8 Mbits/sec    
[  5]   8.00-9.00   sec  1.58 MBytes  13.3 Mbits/sec       
[  5]   9.00-10.00  sec  1.23 MBytes  10.3 Mbits/sec
What th.....?!
I dont get it. Did i miss something obvious?
Any suggestions?

Thanks alot!

TinCanTech
OpenVPN Protagonist
Posts: 11137
Joined: Fri Jun 03, 2016 1:17 pm

Re: Suggestions for a bandwidth issue.

Post by TinCanTech » Fri Jun 11, 2021 7:54 pm

First of all, with the level of equipment you are describing, this is a professional network.

Second, openvpn just uses the network, how-ever you configured the network openvpn will be effected.

Third, openvpn simply runs at full speed, unless you configure it otherwise ..
and you have not even shared your VPN config files or logs.

My crystal ball says: You screwed something up.. and it's not openvpn.

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