Can your ISP see what ports you are using?

[Paddy]

My connection stalled last night and I had to contact my ISP to reinitialise it. I enquired about changing to a better product as my current connection is 1024/256.

My download last month was 125GB So that would be a no. They are happy to continue offering me my current unrestricted package, but it I want a faster download then I will be capped to 20GB/month with £1 for each additional GB.

Now, due to my distance from the exchange, my signal/noise ratio is quite high so I don't think that I would be able to get speeds > 3072/512. As that is the case I cant justify the upgrade.

Now he asked what I used the connection for, and I explained that it cached uncompressed MR/CT/X-ray images onto a local server for diagnostic viewing at home. That is partly true, although bittorrent plays a part in there too.

Can they see what ports I am using? Should I change the bittorrent port so that it resembles that of my medical imaging viewer?

[az]

Of course they can - they provide them to you. The question is whether there are records (there most certainly are records for when you are connected, and probably more, "for everyone's security" - and the record industry - even if you are on an unrestricted plan) and whether the tech has access to them. Many providers also do traffic shaping in that they throttle traffic on popular p2p ports.

[Gurm]

Certainly they can see what ports you're using. Can they tell what data is passing over those ports? No. But a good rule of thumb is to ALWAYS change your p2p ports to something else.

[Paddy]

What port range would you suggest?

[Paddy]

Cheers for the info.

I have changed my bittorrent port to 989 which is FTP over SSL

[The PIT]

Certainly they can see what ports you're using. Can they tell what data is passing over those ports? No. But a good rule of thumb is to ALWAYS change your p2p ports to something else.

I guess this how we caught a naughty boy abusing our network who changed ports

Because protocol analysis focuses on the packet payload and raises alerts only on a definite match, any client-side tricks that use non-default or dynamic ports to avoid detection by P2P applications will fail. Using this approach, the result is normally more accurate and believable, but it still has some shortcomings.

[Gurm]

I guess this how we caught a naughty boy abusing our network who changed ports

Because protocol analysis focuses on the packet payload and raises alerts only on a definite match, any client-side tricks that use non-default or dynamic ports to avoid detection by P2P applications will fail. Using this approach, the result is normally more accurate and believable, but it still has some shortcomings.

Yes of course they can run analysis software. And if they're super-concerned about torrents, and they're scanning for torrent packets, then... well, yeah you're pretty much SOL. But the reality is that most of the time nobody is scanning THAT stringently. Remember that it takes time/resources/money for them to monitor you.

[The PIT]

Gurn your replay go me wondering as we had a naughty boy at the UNI. He was asked to stop using P2P and was blocked. He claimed to have removed it and it popped up on another port as soon as we allowed him back on.

I think ISP's look for large bandwidth hoggers and then study what they're using. When I was on Plusnet they chucked quite a few bad boys onto a very slow network as they wouldn't cut down on the usage.

Of course you ahd the argument that they had signed up for an unlimited usage which was fair enough but then they must have also agreed to the new terms and conditions that Plusnet had sent out.

[Wombat]

It doesn't matter what port you use, BitTorrent is blatantly obvious. Nothing else a computer user does causes so many connections. If they even glance at your traffic, they'll know it's BT.

[Paddy]

perhaps. But there are other legitimate p2p based applications

[az]

BitTorrent isn't illegitimate per se. World of Warcraft patches get distributed over BT, and other legitimate content, too.

[Gurm]

Exactly. There are plenty of legitimate uses for BT, and not every ISP out there is interested in just indiscriminately blocking you from downloading stuff.

[Greebe]

Ditto on that. Was watching a show on CNBC lastnight discussing a private film company who plans to use BT for distributing their works... and especially so once they get into HD movies/vids and such

[The PIT]

A lot do Suse do it for linux.

You've still got to be careful connecting to the wrong sites can get your machine full of crap and I've seen this in action.

Now how can I get the moth out thats climbed inside my keyboard while I was typing.

[az]

You've still got to be careful connecting to the wrong sites can get your machine full of crap and I've seen this in action.

Just use a proper browser and some common sense and that won't happen