ipfs get over one hop not working

[ligi]

to reproduce this I need 3 machines - all run go-ipfs 0.4.21:

machine 1 (lets call 'server' here) has a public IP
machine 2 (lets call 'client' here) is behind a NAT

now I can connect from machine 2 to machine 1 via ipfs swarm connect and get content that is pinned on machine 1

now introducing machine 3 which is in the same network as machine 1 and connect them via ipfs swarm connect in both ways (I think there should be a way to do it one way only - see this coment: #6271 (comment)) so I can get content pinned on machine 1 by machine 3 and the other way around
But now when I try to get content pinned on 3 with machine 2 it is not working. It is directly downloading when I ipfs get the content on machine 1

[Stebalien]

If I'm understanding this correctly, the issue is that machine 1 will not fetch content from machine 3 on behalf of machine 2. This was a planned feature in the original IPFS whitepaper but has a bunch of legal implications that need to be thought through before it's practical.

At the moment, machine 1 can make itself a public relay but then it'll relay traffic for any peer on the network.

[ligi]

Can't machine 1 not just establish a encrypted communication between node 2 and 3 so it does not know the content it is transporting? Was already puzzled that I manually have to connect nodes to get content from A to B - if what you say is true that makes IPFS unusable for me.

[deviousasti]

I'm assuming there's peer exchange happening on all nodes.
But will the public peer be able to assist in traversing NAT?

I can't get 1 to talk to 2. They can both talk to the public peer though.

             +-------------------+ Public Server  +---------------+
             |                                                    |
             |                                                    |
             |                                                    |
             |                                                    |
             +                                                    |
+----------CGNAT+-------+                            +---------Single NAT---+
|            +          |                            |            |         |
|            +          |                            |            +         |
|        Machine 2      |                            |      Machine 1       |
|                       |                            |                      |
|                       |                            |                      |
+-----------------------+                            +----------------------+

At the moment, machine 1 can make itself a public relay but then it'll relay traffic for any peer on the network.

Is circuit relay operational at the moment?

[Stebalien]

@ligi

Can't machine 1 not just establish a encrypted communication between node 2 and 3 so it does not know the content it is transporting?

It can using the p2p-circuit ("relay") transport. However:

Nodes won't relay traffic by default as this can easily run up a large bandwidth bill. However, you can enable this on node 1 by setting Swarm.EnableRelayHop to true.

There's no way for node 2 to know that node 3 is connected to node 1 as well unless node 1 says so by announcing a special relay address. You can do this manually by adding a p2p-circuit address to Addresses.Announce ("/p2p/QmNode1/p2p-circuit").

You can also automatically use a public relay by enabling Swarm.EnableAutoRelay. If you do that, your node will (a) find a public relay and (b) advertise a relay address using that relay. However, node 1 won't automatically be a public relay.

You can make it a public relay by additionally setting Swarm.EnableRelayHop. However, doing so will make your node very popular and may cost quite a bit in terms of bandwidth.

[Stebalien]

@deviousasti

Is circuit relay operational at the moment?

Yes (ish). Nodes will connect to other nodes through relays by default if those nodes advertise a relay. However:

1. Nodes won't act as relays by default unless configured to do so (Swarm.EnableRelayHop).
2. Nodes won't announce relays by default unless configured to do so (Swarm.EnableAutoRelay).

[godcong]

I'm assuming there's peer exchange happening on all nodes.
But will the public peer be able to assist in traversing NAT?

I can't get 1 to talk to 2. They can both talk to the public peer though.

             +-------------------+ Public Server  +---------------+
             |                                                    |
             |                                                    |
             |                                                    |
             |                                                    |
             +                                                    |
+----------CGNAT+-------+                            +---------Single NAT---+
|            +          |                            |            |         |
|            +          |                            |            +         |
|        Machine 2      |                            |      Machine 1       |
|                       |                            |                      |
|                       |                            |                      |
+-----------------------+                            +----------------------+

At the moment, machine 1 can make itself a public relay but then it'll relay traffic for any peer on the network.

Is circuit relay operational at the moment?
i used frp to link machine 2 with a public IP Machine