I've been experimenting with transmission, but I'm seeing a lot of strange net behaviour when (and after) I use it.

+ I have a personal firewall (UFW) with in and out denied by default.
+ I have a house firewall (openWrt) that forwards my torrent port to this machine (that shouldn't get used).
+ I use openVPN using a distant VPN service.
+ I watch all connections using sudo netstat -pcutee
+ And I tail -f /var/log/syslog to watch denied traffic, all in realtime.

As I write this, I'm seeing rejected connection attempts on /var/log/syslog on my chosen torrent port. But that's strange because I stopped my torrent d/l client an hour ago. I was running openVPN at the time. But I'm not using that either(?). I think someone saw me doing torrent and now they're port-scanning me.

Also, its several someones. Using whois ripe, there's one from Yunnan China. There're others from Netherlands and Germany. I have yet to whois all the attempts. And I haven't waded into my openWrt logs yet.

Anyone need me to send excerpted/modified logs? Am I being port scanned? Is this typical? What about all the people that don't have multiple stateful packet firewalls set up to catch all this...and who don't watch the net traffic free-for-all?

One last speculation: I may have poisoned my test since at one point I turned off most things so that my building IP address would have been visible...out of curiosity.

Another thing: I don't get all these bumps in the night when i d/l a linux distro.

Anybody else want to speculate?

Those peers have discovered you and are trying to establish or re-establish sessions with your host. I don't know the timeouts or how long/short it would be before they give up. Further, someone else may shut down their torrent application, it remembers you as a peer and at some random time when they next start their torrent app, it may also try to peer up with your station yet again.

I think the only way to really deal with this is to try and block torrent traffic entirely via a network appliance device, router or gateway. But some security persons may know better.

Clients in a swarm may not be configured to immediately accept inavailability as not being temporary. (Kind of like the same backscatter one had back in the modem days ;-p)


Run tcpdump and save packets to file. That could be more interesting.


Sorry. I favor operating on facts alone, not fiction.

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It's pretty typical. I see it all the time for a few days after I download a popular torrent, and those are typically Linux distributions. It's worse right after a new release becomes available, when there are just a few seeds and lots of leechers. As other downloaders exchange the list of peers they have seen, it can take a while for you to be forgotten. There isn't much effect beyond clutter in your firewall logs.

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