“Is there any mechanism to ensure the integrity (i.e., non-modified nature) of the downloads/uploads?” - David A. Lessnau
Yes, there’s several layers to this:
The .torrent file itself contains an overall integrity check (SHA-1 or MD5 sum, I think) for each file in the torrent.
For each piece/chunk you transfer, the sending peer notifies you of the intended hash of the piece.
To prevent “poisoning” of the torrent (i.e, someone deliberately sending false data) - clients record those who consistently send bad data and refuse to communicate with them.
To prevent someone consistently leeching and giving nothing in return, (most) clients operate on a “tit-for-tat” arrangement. i.e if you send me data, I’ll send you data more regularly/faster.
If you don’t return any data, you will still get some data, but at a slower rate.
This also stops someone with access to high-bandwidth connections “soaking up” all the available bandwidth (i.e to prevent/slow down the distribution of the torrents)
"you don’t need a seed, as long as the peers have all the pieces amongst them.- nordsieck.
This needs reiterating - a lot of people seem to think that you always need a seed. If, between all peers, there is at least one copy of all pieces in the torrent, the seed can disconnect and the remaining clients will share completed pieces. It operates slower (you lose a peer which had all of the data), but will recover given time.
“Stability. I’ve tried various Bit Torrent clients (and client versions) and with the exception of the WoW updater, all have caused my firewall, antivirus, or both to crash. Then the Bit Torrent clients crash themselves” - Tom.
This is a sign of an incorrectly configured system, client, and/or network - and possibly failing hardware too.
Some routers don’t handle having many open connections, some don’t clear their NAT tables (for instance, the default Linksys WRT54G router firmware won’t flush NAT tables - you need to power-cycle it). Some routers can’t handle high volumes of traffic from many sources at once. You can mitigate this by reducing the number of torrents open, capping traffic to less than the full line-speed of your connection, and altering your Bittorrent client to keep less connections open at once.
If your antivirus software is locking up, then I suggest making these changes:
Some Bittorrent clients (such as uTorrent and Azureus) allow you to configure an “incomplete” folder. Configure your Bittorrent client to download to a seperate folder (eg: “X:\Bittorrent-Incomplete”), and when completed - get it to move to your normal use folder. eg: “X:\Bittorrent”
Remove the Bittorrent-Incomplete folder from your Antivirus scanner’s watch list.
This will stop your AV software trying to lock and scan files that change constantly. (Which can in turn cause your torrent client to lock up/crash when it needs to modify the file again)
- If your firewall is crashing due to bittorrent, then get another firewall, or configure it properly (i.e allow all incoming connections to your BT client). If you are using a modern software firewall on your PC, then it can open those ports automaticly when you load your Bittorrent Client.
Regarding the super slow downloads/availability: This sounds like either a problem with your network configuration, or using poorly shared torrents.
If you are using a NAT router or similar, you need to either enable UPnP, or manually forward certain ports - then configure your BT client to use those ports for incoming connections.