Performance issues

[FPyro 2]

Hi!

I have noticed a really strange problem. I'll try to explain it just as it happens.

Without connecting to the vpn, I can run a speedtest which gives me good 80-90Mbit/s. I can run the torrent client, run a stream and run a speedtest at the same time, almost maxing my connection.

Now, when I connect to a vpn, and I've tried 3 different german servers now, I can run a speedtest, which gives me good 30-60Mbit.

As soon as I start my torrent client, the performance issues become apparent. Having the client running severely impacts the speedtest, which goes to about 10Mbit, although the torrent client needs only a few hundred kbit/s.

My average speed while running the stream and the torrent client reach peaks of about 1Mbit/s, averaging about half of that, making the stream unstable.

Torrent performance seems to be about 20% compared to my normal ISP connection (public tracker, always same torrents, same client) - with stream (1080p) off.

I also noticed that my TCP/UDP established connections are rather high as soon as I connect to the vpns (going to about 260 connections total).

Can anybody explain to me this very strange issue. I noticed it before somewhat, but never performed these specific tests.

It kinda feels like a sort of traffic shaping, because the speedtest gives great results, but as soon as the torrents start downloading, everything gets slow and the stream laggs.

Please help me!

[Staff 9972]

Hello!

Please make sure that you have no "defense" program which might wrongly identify UDP packets as an attack and subsequently start to drop packets. When you connect over OpenVPN, all the packets come from the same IP and port on your physical network interface, regardless of the real protocols and applications you use (as you know): the real headers and payload are still encrypted when a packet arrives to your physical network card (the decryption occurs later, when the packets are on the tun adapter they are already decrypted). Having a massive amount of UDP packets all coming from the same IP and toward the same inbound port may trigger a flood alert for some firewall or network monitor/packet filtering programs.

Kind regards

[FPyro 2]

Hi!

OMG! You are a genius. This problem lead me to subscribe to 3 different vpns now... I blamed air at first, just because of no other explanation, but the problem persisted with every server.

Now, I started utorrent, download got to about 100kb/s, upload wouldn't go proberly at all.

-- > DISABLED COMODO FIREWALL!

-----> Speed EXPLODED...right away, literally. Download going to 800+kb/s, download now stable at about 300kb/s. This is absolutely insane. I actually didn't believe you before somehow

... so sorry, but when it just wouldn't work, I followed your advice, with extremely unexpected results.

The question is, WHY does comodo firewall mess up the torrent speeds. I allowed utorrent of course, and openVPN and Air and everything else. How must I configure the firewall to still defend my pc without blocking my filesharing?

Thanks so much, you're awesome! Never thought comodo would do such a thing...

[Staff 9972]

Hi!

OMG! You are a genius. This problem lead me to subscribe to 3 different vpns now... I blamed air at first, just because of no other explanation, but the problem persisted with every server.

Now, I started utorrent, download got to about 100kb/s, upload wouldn't go proberly at all.

-- > DISABLED COMODO FIREWALL!

-----> Speed EXPLODED...right away, literally. Download going to 800+kb/s, download now stable at about 300kb/s. This is absolutely insane. I actually didn't believe you before somehow

... so sorry, but when it just wouldn't work, I followed your advice, with extremely unexpected results.

The question is, WHY does comodo firewall mess up the torrent speeds. I allowed utorrent of course, and openVPN and Air and everything else. How must I configure the firewall to still defend my pc without blocking my filesharing?

Thanks so much, you're awesome! Never thought comodo would do such a thing...

Hello!

Glad to hear it.

Some things to check on Comodo:

- logging: an excessive logging may slow down the whole system

- in the "Advanced" tab of the "Firewall Behavior Settings", the following items must NOT be selected:

"perform protocol analysis"

"block fragmented IP datagrams"

and finally probably the most important thing to check: make sure, when you're connected to the VPN, that no task/process is flooding Comodo with an attempt to send packets outside the tunnel (even if they are not harming because directed within your private network, typical example Windows system tasks which start sending an incredible amount of packets toward broadcast addresses under rare conditions). You can check that on the "View Active Connections" windows or even better in the Comodo logs (if you enabled logs for the Block rule(s)).

Kind regards

[FPyro 2]

Hi!

Alright, I believe I fixed it now!

Somehow incoming UDP connections to my virtual network card (beginning with 10. ) got blocked.

The destination port was the same port used in utorrent.

So I created a global rule "Allow UDP in From MAC Any To In [VPN] Where Source Port is Any And Destination Port Is Any"

I thought about putting the torrent port as destination port, but I have it change randomly...

The VPN Network zone is defined as [10.0.0.0 - 10.255.255.255]

Hope that rule is safe?

At least now I don't get all those blocked incomming connections anymore

[computerninja 0]

I am trying to figure out why DL speeds are so slow in utorrent.

I've tried the port forwarding technique outlined on your site where you keep the fields blank and generate a port to forward. Then I use that port created here and enter it in my utorrent client.

I get download speeds like 4kB/s. When I'm not connected with AirVPN, I get download speeds over 100kB/s for these specific torrents.

I left my Windows 8 firewall alone.

Any help would be appreciated.

[Staff 9972]

@computerninja

Hello!

Your post has been moved into this thread which might provide you with some important hints.

Kind regards

[RaggaMuffin 0]

The thread is very helpful.

I'm running on a Windows 7 x64 system.

I'm afraid I have severe problems as soon as I am launching my utorrent client.

As soon as it is running web pages are loading very slow or even fail to load at all.

Streaming radio isn't able to hold it's connection. The windows firewall is disabled.

Port forwarding is set up as it should. The client is working fine, even so it feels slow.

There is no other firewall interfering with traffic. And no anti malware program that's

actively scanning traffic. The only things in the background are AVG Anti Virus and

OpenDNS. I just tested disabling the Anti Virus, to no effect. Which I wouldn't have

expected to have one.

I'll be glad to provide further information. I can't shake the feeling I'm missing something.

Kind regards

[Staff 9972]

@RaggaMuffin

Hello!

Please make sure that the torrent client is not "strangling" your line with excessive upload or download bandwidth (if you have an asymmetric line, saturation of upload bw will clog download bandwidth as well). Set your torrent client upload and download limits in order not to exceed 75-80% of your total available bandwidth.

Additionally, test different ports and protocols (in particular, try 53 UDP and 80 TCP) just in case your ISP performs port shaping.

Kind regards