I have tried to make connection between several nodes in my private network, but I do it with a direction enode, but Ethereum network does it without knowing my address enode, I want to know what kind of p2p communication protocols used so that all nodes are communicate with each other, and if that code is free.
when start the geth your need some config enode to connect to
by using the p2p network(kad) discover function, geth will discovery other nodes.the discover function can be disable by using --nodsicovery command line arg.
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I'm working on a data sharing app using node js, the idea is to create an application that can connect peers using node-js without using any kind of central dependency i.e a signalling server or something of its kind. After a lot of research I'm always back to this diagram but it only makes sense if there is no signalling server I'm targeting LAN networks so that I don't have to deal with NAT.
To be specific, I would like some to answer these specific question
Is it possible to connect to webrtc on LAN, i.e the webrtc connection will connect using my client's ip
Is it possible to use websockets without a central server, or something like websockets
Is it possible to connect two clients on LAN using node js without using any hardcoded Ips or asking users to enter ip.
Since you are using node.js, you can very well use raw UDP (dgram) and use UDP broadcasting for device discovery - then you do not need any form of centralization required by websockets/webRTC.
The answer to all your questions is Yes!
Also, there is a lof WebRTC server that you can use them on a simple Linux box, like Janus, Kurento, etc. I've tested them and they have worked with some mischief, lol. So, run it and next read their API to exchange anything you want on their medium.
I'm not sure about Janus but the Kurento has a nodeJS client itself. Read the Local Installation and JavaScript Kurento Client.
Additionally, if you want to make a WebSocket connection, it has enabled by default configuration.
To change the port, enter this command at the final step:
npm start -- --ws_uri=ws://https://185.164.72.144/:8888/kurento --as_uri=https://185.164.72.144:6008/
I read a lot about how bitcoin clients find each other. I would like to do a fork from bitcoin and I have a question. How my network will differ from bitcoin? How the node found by my client will understand if this is bitcoin's client or mine?
How my network will differ from bitcoin?
You will need to change the network magic for your protocol messages so the nodes on the bitcoin network can easily distinguish your network messages and theirs.
https://en.bitcoin.it/wiki/Protocol_documentation#Message_structure
How the node found by my client will understand if this is bitcoin's client or mine?
Assuming you are using the same protocol as in Bitcoin, once you change the network magic field, it should be sufficient for your fork to distinguish between messages intended for Bitcoin network and your network.
Ok. I am creating a teamviewer like app. And p2p connection is the best route based on my research on p2p. I want to know weather teamviewer works fully on p2p, and is it possible to create such an app without using any dedicated server and a static public ip address. I mean i do know all nodes in a p2p n/w act equal, but then how will these maintain a connection having dynamic ip addresses. Hoping someone can explain how p2p establishes this.
They do not need a static IP. But in absence of a static IP you need some discovery / address exchange mechanism that allows nodes to find each other.
Overlay networks like DHTs/gossip protocols/supernodes are generally used for such a thing, but it could be as simple as a user manually entering the current IP address.
In practice reachability is a much bigger concern. NATs and Firewalls may prevent incoming connections. If both nodes cannot accept incoming connections then neither can connect to the other.
I want to create peer-to-peer connections between 2 nodejs client.
using websocket (dnode)
here is the limit:
nodejs client run at 2 pc which is in different network.
they don't have static ip (192.168.1.100 && 192.168.2.200) behind NAT or firewalls
no permission to change the mapping of router.
has only static web server in public network. (can change the file by human)
can install application at pc (win)
is it possible? thanks
May be you can use PeerJS to achieve your objectives.
PeerJS simplifies WebRTC peer-to-peer data, video, and audio calls.
PeerJS wraps the browser's WebRTC implementation to provide a complete, configurable, and easy-to-use peer-to-peer connection API. Equipped with nothing but an ID, a peer can create a P2P data or media stream connection to a remote peer.
Also to broker connections, PeerJS connects to a PeerServer. Note that no peer-to-peer data goes through the server; The server acts only as a connection broker.
If by peer to peer connection, you mean direct connection between the peers (i.e., not via a server) then yes it is probably possible in theory in most cases. But I have never seen someone who has implemented the solution.
You would need to implement a NAT hole punching system for TCP connections (they are not always 100% successful because of technical constraints which can't be solved at the software layer). Then, you'd just need to implement the websocket protocol on top of this tcp connection.
If by peer to peer connection, your are ok that communication passes via a central server (with a public address), then yes it is possible too. Both peers just need to connect to the central server, and it should just transfert the traffic between both peer.
I'm trying to understand how can a magnetic link work, as I've read they use DHT and PEX to get the peers, but if I'm a new node in the network how can I find peers with only the hash of the file?! Doesn't it always require a link to a known host?
Thanks
The bittorrent DHT can be bootstrapped in many ways. It just needs the IP and Port of any other reachable DHT node out there.
Current clients generally use several of the following strategies:
bootstrap from a cache of long-lived nodes from a previous session
use a DNS A/AAAA record mapping to a known node (e.g. router.bittorrent.com or dht.transmissionbt.com) with a known port
use a node embedded in a .torrent file
retrieve the DHT port from a bittorrent client over a bittorrent connection established through other means, e.g. a conventional tracker.
If a peer is embedded in a magnet link one can also piggyback a DHT bootstrap on that through the port message
multicast neighbor discovery via LSD
cross-chatter from the IPv4 to the IPv6 DHTs and vice versa (if needed)
Other ways such as user-configurable bootstrap lists, DNS SRV records round-robin mapping to live nodes or - should everything else fail - adding the IP of your friend(s) manually work.
Once a node has joined the network the first strategy mentioned above will kick in and it is unlikely that it will have to bootstrap again.
So while most implementations rely on a single/few points of entry into the network for convenience, the protocol itself is flexible enough to decentralize the points of entry too.
Just for emphasis: Any node in the DHT can be used to join the network. Dedicated bootstrap nodes are an implementation detail, not part of the protocol, and could be replaced by other discovery mechanisms if necessary.