Virgin block torrent ports?
Sadly, I think Si Clement's assertion that Virgin don't do deep packet analysis may no longer be true. There seems to be a lot of conflicting experience - people reckoning torrents are limited to 10K, port 80 blocked etc.
Maybe it's subscriber- or area- specific, possibly in part contingent upon which company previously owned the infrastructure (mine used to be Telewest, I think).
For me, (and I am qualified to figure this out: I'm not scrabbling around in the dark with NAT settings and port forwarding; I Know What I'm Doing) I can say that, on the XL service I'm on, I've not found any blocked low-numbered ports, indeed no ports up to the ephemeral range seem to blocked by default. Incoming web and ssh traffic works fine with proper setup. Nor are torrent speeds restricted per-se.
BUT (and it's a big But) incoming torrent connections ARE blocked dynamically, regardless of port chosen. Kill all the torrent clients and wait for a while and the blocks are lifted. Port forwarding checks out properly and definitively using plain TCP listeners on the relevant port(s). Start a torrent client though and the port is blocked. No throttling, no disconnects, just blocked.
US customers of Comcast have similar issues - they're connected via Sandvine devices which analyse traffic and purposely disrupt bit torrents by issuing bogus TCP resets. VirginMedia don't seem to issue resets, they just black-hole incoming connections - the connections just time out.
This isn't throttling or any sort of volume-based limitation, nor does it depend on time of day. Half a meg at 4 AM, makes no difference, as soon as torrent activity is detected, the port is blocked. Switching ports and/or encrypting torrent traffic makes no difference, so the block must be triggered by tracker activity rather than the main torrent traffic.
I thought at first maybe it was denial-of-service protection triggered by lots of incoming connections, but without a torrent client running, lots of connections (to the same port) work just fine.
(I confess I've not pushed this non-torrent testing to the point of triggering any actual D.O.S. defenses, if any exist. I might still be wrong about the whole thing - I'd be delighted to be proven wrong, in fact :-) )
Could it be Virgin smell a competitor in the "content provision" marketplace, who they're not about to allow to deliver via their cable infrastructure? Azureus these days styles itself a content delivery platform for digital media, particularly low budget film, trailers, pop videos and pay-per-view film and so on.
Are we going to see the BBC's iPlayer "traffic shaped" into submission, too?
What other content or connectivity are they going to quietly alter, block, throttle, or otherwise adjust?
As others have said, though BT's service is neither the cheapest nor the fastest, at least with BT's ADSL you don't get this kind of meddling with your traffic - sure they (theoretically) cap bandwidth but I'm not a heavy enough user to have EVER fallen foul of that. For occasional bit torrent use (Linux distros and VMWare/QEMU disc images, say) the 5M BT ADSL connection I used to have was quicker than my outward-connections-only 20MBit virgin cable broadband presently is (though my web browsing & downloads have speeded up, subject to following Virgin's timetable and avoiding peak hours where presumably I should be dutifully watching Virgin TV and/or paying for Virgin pay-as-you-w...er..whatever... porn).
From what I gather here, plenty of Virgin customers with a much "better sounding" so-called 10Mbit cable connection would be rather better off with 5Mbit BT ADSL.
Ho hum. In the immortal words of Jagger and Richards, you cain't always get what you want...
FWIW, if I actually watched the telly I would still reckon the virgin cable and broadband package considerably better value than Sky, and I can't see the Murdoch empire being inherently any cuddlier or less consumer-hostile than Branson's, but still, it's less attractive if you need a proper un-interfered-with internet connection and have to buy a BT one on the side. Hopefully their marketing types will eventually realise this.
This rant brought to you via an alleged 768/20000Kbit, during the Forbidden Hours best suited for short bits of text.