INFO:TriblerTunnelCommunity:Could not create circuit, no available exit-nodes

[teddyrogers]

Tribler 8.2.3 Build 179, is anyone else experiencing, "no available exit nodes", are the three to four Tribler exit nodes still working? I tried two separate systems and I couldn't get any traffic on either of them whilst using any level of anonymity. Everything works fine using zero hops.

Checking in, "Debug -> Tunnels -> Circuits & Peers", there are no exit nodes listed.

Ping tests are returning, "Destination Host Unreachable"

[qstokkink]

I would like to kindly request you, for the second time, to stop posting exit node ips. I purged them from this issue's history.

I can reproduce this. I also confirmed that our GoldenRatioStrategy is still working and dropping relay peers to try and find exits.

[teddyrogers]

I would like to kindly request you, for the second time, to stop posting exit node ips. I purged them from this issue's history.

Noted. However, since I have seen others posting similar information (e.g. issue 8795), and nothing being mentioned of it, I thought it was not a problem any longer.

I can reproduce this.

Thank you for confirming. Could this have been part of the problem in #8787 as I noticed similar performance issues before the stop in traffic?

[qstokkink]

issue 8795

Oops. Thanks for pointing that out. Fixed.

Could this have been part of the problem in #8787 as I noticed similar performance issues before the stop in traffic?

It could be. We have some users that find exit nodes and others that don't. We're currently investigating what could be causing this.

[teddyrogers]

We have some users that find exit nodes and others that don't. We're currently investigating what could be causing this.

Is this a weakness in the Tribler network? I don't want to beat a dead horse but... this event ties in to what I was trying to explain, as a possibility of shutting down the network, in #8612

[qstokkink]

Yes. This is the weakness of Tor and Tor-like technology like Tribler. That hasn't changed since my answer in #8612 (see there for a longer answer): if anyone takes down all the exit nodes, you can't download anonymously.

[teddyrogers]

This is the weakness of Tor and Tor-like technology like Tribler.

That is why I was suggesting it would be good if the Tribler network had more and diversified exit nodes across different regions.

There are a couple of other things I noticed during this outage;

1. If connections to the IP exit nodes/ hostnames are blocked this prevents Tribler from working in anonymity, no matter the hop count. This seems to suggest that Tribler always needs to communicate directly with the exit nodes for it to function in anonymity?
2. I tried a torrent in the IPV8/ overlay network, from a Tribler located in the Netherlands, that is still connected and working with the exit node/s. I wasn't able to start or share the torrent within the overlay network, whilst the exit nodes are down. Again this leads me to suspect Tribler is broken, working within the overlay network, if it cannot connect to the exit nodes?

[qstokkink]

communicate directly with the exit nodes for it to function in anonymity

This "directly" depends on the hop count. If you have 1 node/hop in your circuits: correct. However, if you have multiple hops, you indirectly communicate with an exit node.

Regarding your second point: we're still investigating this part.

[teddyrogers]

This "directly" depends on the hop count. If you have 1 node/hop in your circuits: correct.

I should add, my comments here are based on anonymity being set to either two or three hops. I am aware one hop is directly connecting to the exit node. Even with hops set to two or three there is no connection to the exit node via another Tribler or sharing of torrents with another Tribler within the overlay network.

[SOglf]

I also lost all connectivity to exit nodes ip address space, whole /24 block. ISP level or an attack, or BGP hijack, who knows. Can confirm the same behavior.
ALSO: tribler is unable to build circuits, with 2 or 3 hops to those exit nodes, BUT, read carefuly: Tribler in a different location, where a DIRECT IP access to the exit nodes is possible, WORKS.

Also, please read carefuly:

1. After doing extensive tests for weeks, two Triblers WILL NOT share a torrent inside the overlay/ipv8 network in the sense of a connection between them. No matter what. Connection always go through an exit node and back into tribler network. This breaks a basic use/understanding of the tribler network and puts a very high load on the exit nodes. I would propose, to change connections a bit, and if there is 1 hop set, or 2, or 3, Tribler SHOULD:
   a) Connect to a random RELAYING peer.
   b) Request a rendezvous with another peer INSIDE THE TRIBLER NETWORK, which has the torrent. DO NOT CONNECT TO AN EXIT NODE.
   c) The other peer should also open a connection to a different RELAYING peer, and then from there to the rendezvous point, STILL INSIDE THE TRIBLER NETWORK.
   Tribler is ALREADY able to relay traffic inside it's network, I see completely NO REASON for two Triblers unable to communicate with each other via 2 hops or more. Also "hidden swarms" in debug mode always show ZERO peers/seeders.

It would tremendously lower the exit node loads and would allow tribler to work even without a single exit node.

I would also like to know if this is an ABNORMAL behavior, or it was DESIGNED this way. I understand there is basically only one maintainer right now and I really respect that, HOWEVER there may be a very big design flaw if Tribler was designed NOT TO carry traffic inside it's own network directly between peers possessing the wanted torrent file.

[teddyrogers]

@qstokkink for the past 12 hours

1. I have had Tribler running here, with hops set to three, running a single torrent for testing.
2. My Tribler is unable to reach the exit nodes.
3. There is a Tribler in the Netherlands, that has the same torrent with his hops set to three. He can still connect to exit nodes.
4. We are unable to share the same torrent over IPV8.

Is Tribler fundamentally broken, if we cannot connect and share torrents between Tribler users, within the IPV8 network, without us both being able to reach the exit nodes?

There seems to be some validity with issue #8727 and the event here, that could be further investigated. I tried to highlight in post #8727 (comment) if this was normal behaviour, if whilst using two or three hops, the exit node needs to be contacted?

[qstokkink]

I would also like to know if this is an ABNORMAL behavior, or it was DESIGNED this way.

@SOglf The "hidden swarms" should work exactly as you described/proposed. Tribler was indeed designed to "carry traffic inside it's own network directly between peers possessing the wanted torrent file". If this isn't happening, this is indeed broken/abnormal.

@teddyrogers we are indeed investigating. Regarding "if whilst using two or three hops, the exit node needs to be contacted": when contacting the open Internet: yes. However, Tribler-to-Tribler communication should not need an exit node, i.e., "hidden swarms", but this is apparently broken (see my answer to @SOglf).

[qstokkink]

I just wanted to give a bit of insight into what we are doing about this very disruptive event. A little wrap up of what we found so far:

• Some people connect just fine and others don't.
• We used VPNs to confirm that, from some locations, no packets receive a response from exit nodes.
• This does not seem to have to do with IPv4/IPv6 or other protocol support related things.
• On affected machines, this lack of responses happens for older Tribler versions as well, which were previously working just fine.

Our current working theory is that some ISP(s) has/have started blacklisting Tribler's exit node IPs and we have found some blacklist registers that have Tribler's exit nodes listed. Our response - so far - has consisted of an "unblacklist"/whitelist request to those blacklist registers. We are still contemplating our following moves.