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ZoneAlarm— the culprit

Mark’s post got me back to use BitTorrent after a few days lay-off. It wasn’t that I was too busy or anything (you just keep the client running in background, eh?) but the thing simply didn’t work. I started with BitTornado and switched to Azureus , to no avail.

On the university network, one basically got very bad speed because the firewall won’t allow inbound connections (and rightly so). But I thought at home things will be better. The firewall in this case is my router, which is under my complete control. (Buwahahahahah!!!)

But things didn’t work out as planned, and I got this nasty stuff where after a few minutes downloading, either of this happened:

  • The connection stalled completely, not just for BitTorrent but the whole computer.
  • My CPU usage goes up to 100% and everything stops.

I was wading through too many forum posts to remeber, yet I could not solve this problem. The general answer is that one should

  • open up incoming TCP connection in the range 6881-6889 (or all the way through 6999) and forward the port to your local machine.
    I could not do this because my router ( D-Link DI-624+ ) only allow forwarding of single port and not port ranges.
  • OR set up a port triggering scheme, where an outbound connection on the trigger port (in this case TCP 6969) opens up specified port(s) for inbound connection (in this case TCP/UDP 6881-6999)
    This is quite convenient as you can use dynamic IP with DHCP and it will still work. And this is what I did.

But the symptoms prevailed. Until I came to sense and check out the place I ought to have checked out first of all, the Azureus wiki . I got my answer within minutes, and it is clear the trouble was.

The Zone Labs firewall products Zone Alarm 5.0, Zone Alarm Pro 5.0, and Zone Alarm Security Suite 5.0 are not compatible with Azureus due to an issue with their TCP filter, TrueVector (vsmon.exe) Usual symptoms of this issue include but are not limited to 100% CPU usage, slow transfer speeds, corrupted files, trouble establishing incoming and outgoing transfers, complete network outages, complete system freezes, random reboots, and blue screens of death.

Disabling Zone Alarm’s firewall protection will not solve the problem as its filter will still be running in the background. A complete uninstallation is required. This issue is not limited to Azureus, and has been confirmed by users of many other filesharing clients including BitTornado, ABC, Shad0w’s Experimental, EMule/Gnutella, and Shareaza.
Azureus wiki—ZoneAlarm

After reading a few online reviews, I learnt that Outpost Firewall by Agnitum does not suffer the above problem. So I uninstalled ZoneAlarm (it puts up a fight though, had to restart into safe mode) and put in the free version of Outpost.

It’s a very nice piece of software, very intuitive. ZoneAlarm is good for newbie, if you know what you’re doing this is a much more powerful personal firewall. (And I don’t even need the pro features , so it’s free all the way.)

As I’m writing this Azureus is happily downloading at 50kB/s, give and take. 🙂


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