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OpenVPN Connection Loss Issue
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OpenVPN Connection Loss Issue

TheOnlyDKTheOnlyDK Member
edited September 2015 in Help

I'm having this weird issue with my OpenVPN server. I'm able to connect to the server just fine, able to browse the sites and etc, all are fine until if I use a lot of bandwidth (youtube, speedtest.net, etc) then which it will just have no more connection until I restart the connection (or wait a super long time).

I am still able to ping the VPN server and the VPN server can still ping the internet, but I won't be able to directly ping the internet when connected to the VPN.

Anyone know what might be the cause of this? Could it be that the VPS provider has some sort of monitor tool that will cut the connection for a period of time if it uses a lot of bandwidth?

Comments

  • its propabbly your dynamic connection or like that.

  • @RockBeltHOST said:
    its propabbly your dynamic connection or like that.

    What do you mean by that? My other servers are fine, just this one server is having issue, so it shouldn't be the setup or my connection.

  • CasterCaster Member
    edited September 2015

    @TheOnlyDK said:
    What do you mean by that? My other servers are fine, just this one server is having issue, so it shouldn't be the setup or my connection.

    can you ping and do traceroot from your PC to the vps and provide the info here . mask the servers IP and your IP when posting.

  • I don't have anything to post actually. When the connection fails, everything times out.

  • when OpenVpn fails just disconnect and trace route the VPS IP then if the issue is on the servers network you can figure it out

    if the above traceroute didn't show any signs of packet loss then just reinstall the OpenVPN server on a Fresh OS

  • If I disconnect the VPN, I can traceroute the server IP just fine, the server seems to be online all the time just my VPN has no connection. But if I reconnect again, it would work again until I use a lot of BW.

  • do you setup it up using nyr script

  • @simonindia said:
    do you setup it up using nyr script

    Yes and I manually installed it too, nothing changes.

  • @TheOnlyDK said:
    Yes and I manually installed it too, nothing changes.

    Hello are you using UDP or TCP, also did the VPS has a capable of high port? is it 100mbps nor 1gbps on port? this could be also a scenario also iptables is on eth0 check your ifconfig please if your eth0 or venet0 then if venet0 then set the rules to venet0.

  • It's using UDP. I'm sure all the rules are correct and set to venet. If iptables are set to use the wrong interface, then it should not work at all. Port speed of the server should be irrelevant to this issue shouldn't it?

  • Check your mtu

    Thanked by 1TheOnlyDK
  • @TheOnlyDK said:
    It's using UDP. I'm sure all the rules are correct and set to venet. If iptables are set to use the wrong interface, then it should not work at all. Port speed of the server should be irrelevant to this issue shouldn't it?

    MTU is depend also in your port speed. If port speed is much lower MTU won't effect it must be balance just use default tun-mtu 1500 nor me don't use tun-mtu. or don't use comp-lzo neither.

    Thanked by 1TheOnlyDK
  • @Trollburn said:
    MTU is depend also in your port speed. If port speed is much lower MTU won't effect it must be balance just use default tun-mtu 1500 nor me don't use tun-mtu. or don't use comp-lzo neither.

    I'll check my mtu and maybe disable lzo and see how that goes. It's late here, will try tomorrow. Thanks to all who helped.

  • singsingsingsing Member
    edited September 2015

    TheOnlyDK said: Anyone know what might be the cause of this? Could it be that the VPS provider has some sort of monitor tool that will cut the connection for a period of time if it uses a lot of bandwidth?

    Hard to tell if this is actually what is going on, but, I'd say that, yes, this is possible.

    TheOnlyDK said: It's using UDP.

    That's a bummer, and possibly the problem, because there's no "gentle" way to throttle UDP.

    With TCP, hosts can be told to pipe down by anything that the traffic passes through:

    https://en.wikipedia.org/wiki/Explicit_Congestion_Notification#Operation_of_ECN_with_TCP

    And the OS will respect this, independently of the application. Whereas, with UDP, there is no way for the OS to tell the application (in this case OpenVPN) to slow down. That is, it wouldn't work even if anyone bothered to define and set ECN bits for a UDP protocol. The reason it works for TCP is the application is -blocked- from sending more if the kernel buffer is full, and UDP does not have this concept. Try TCP (in the hope that you'll get consistent, shaped performance). Or try tuning OpenVPN parameters, it should have some parameters, at least in UDP mode, to control the transmission rate.

    Thanked by 1TheOnlyDK
  • @singsing said:

    Well, I tried TCP, seems to be fine. Did a speedtest, it completed just fine. The speed got reduced 50% however, but at least it works :)

    Thanks

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