I recently started using AVAST! antivirus home edition and I am quite pleased with it. However, I recently noticed one potential problem with it. I am using openVPN openvpn.net to run my own private virtual network. I run this on a windows XP Pro machine. When I have all the providers on in Avast, there seems to be a MAJOR performance hit to my VPN. Things seem to slow down to half the normal speed (when Avast is off) and pings are frequently dropped between machines connected via VPN. As stated, when I turn off all the providers in Avast, this is not a problem, so clearly it is Avast causing the problem. Does anyone know how I can make Avast not scan things going through the VPN? That would be great. Thanks alot.
What if you stop the providers one at a time - is there a particular one that’s causing you the troubles?
I thought the web provider and the network provider would be the most resonable places to start, but turning them off on both host and client do not seem to make a great difference. The main thing that changes the speed is when I stop on access protection on both the host and client. This speeds things up considerably.
It not a surprise having a speed increase. Not scanning, not using resources… Otherwise, you lose protection 
It not a surprise having a speed increase. Not scanning, not using resources... Otherwise, you lose protection
I think you missed the question I asked –
Does anyone know how I can make Avast not scan things going through the VPN?
The VPN is behind 2 firewalls (hardware and software) and has 2048 bit encryption on the keys. I think its ok to turn off the scanning at this point because I have the scanning on for the main system. I am more interested in telling the scanner not scan data only on specific internal networks. My point was that I KNOW the scanner is causing the performance loss, I want to turn it off selectively.
Well, what provider is it then, if you say Web Shield and Network Shield don’t make any noticable difference? It has to be one of them… maybe Standard Shield?
Does the avast! icon spin often when you are connected through the VPN?
Ok, after much effort I have figured out it is a combination of the following that limits the speed of the VPN. Turning off Instant Messaging, P2P, and Standard Shield on the client allows me to get much better transfer speeds between host and client. However if anyone of these is turned on, the speeds go right back down. At this point, I am stuck. There doesn’t seem to be any setting to tell teh program “do not scan data coming on/going out on a specific IP range”.
Such an exclusion doesn’t really have much sense - these providers are disk related, i.e. they monitor the disk access. They have nothing to do with network traffic.
I would say to check if the avast! icon spins on the target machine (which would imply that the providers are really scanning something) and to find out what is it scanning - and possibly to put the relevant folder/file into the list of exclusions. However, the symptoms don’t seem to be right to me - I somehow doubt that the target machine uses P2P and IM programs so heavily and simultaneously.