MultiChain Developer Q&A - Recent questions tagged network

VM won't connect to multichain on another VM

Thu, 23 Jul 2020 13:56:07 +0000

I followed the get started tutoial and set up my own blockchain on an Azure linux VM, I set up another VM and when I ran the multichaind mychain@IP:Port command it gives this

Error : can not connect to mychain@IP:Port make sure Multichain is unning on port.

my first vm's ip adress is : 20.188.57.6, my second's IP is 20.188.59.71. But the IP they give me to connect with is different from the public one.

Another question is : do all of my nodes have to be in the same network as my root node or I can connect from other networks?

Random ports in peer handshake

Sun, 19 Jul 2020 08:22:39 +0000

While looking at the output of getpeerinfo api call, there are random ports on addr and addr local fields. I have set the default network and RPC ports.

I have set the default network ports to be 6001 for both the nodes and connected the daemon by on the same port.

here is an example

[
    {
        "id" : 3,
        "addr" : "11.0.2.19:6001",
        "addrlocal" : "10.0.2.218:40384",
        "services" : "0000000000000001",
        "lastsend" : 1595145954,
        "lastrecv" : 1595145954,
        "bytessent" : 33682716,
        "bytesrecv" : 68302709,
        "conntime" : 1592493648,
        "pingtime" : 0.100124,
        "version" : 70002,
        "subver" : "/MultiChain:0.2.0.10/",
        "handshakelocal" : "1QEXPURG6es3LhbUNux2DELwwJyB1Jqvd9xnV4",
        "handshake" : "14MwcB2MQxLT9bcfUJR5vRrnJdJ8RWAeGGnVV5",
        "inbound" : false,
        "startingheight" : 2734,
        "banscore" : 0,
        "synced_headers" : 8676,
        "synced_blocks" : 8676,
        "inflight" : [
        ],
        "whitelisted" : false
    },
    {
        "id" : 28,
        "addr" : "10.0.4.238:59848",
        "addrlocal" : "10.0.2.218:6001",
        "services" : "0000000000000001",
        "lastsend" : 1595145954,
        "lastrecv" : 1595145953,
        "bytessent" : 6403475,
        "bytesrecv" : 356378,
        "conntime" : 1595140368,
        "pingtime" : 0.05432,
        "version" : 70002,
        "subver" : "/MultiChain:0.2.0.10/",
        "handshakelocal" : "1QEXPURG6es3LhbUNux2DELwwJyB1Jqvd9xnV4",
        "handshake" : "1ZqTLXmJHvWrvpTniZuT4vusFBS1XUqWrZxkLL",
        "inbound" : true,
        "startingheight" : 87,
        "banscore" : 0,
        "synced_headers" : 8675,
        "synced_blocks" : 8675,
        "inflight" : [
        ],
        "whitelisted" : false
    }
]

Is this normal behavior? Will it cause any problems if there are firewall rules in place that only allow communication through the default network port?

Thanks

How to create transaction filters?

Fri, 24 Jan 2020 05:15:14 +0000

Hello everyone,

I am a beginner. Currently I have started to learn Multichain's transaction filter. But when i read the documentation i am not able to understand that how do i start creating transaction filters? Where it should be located? How it is processed by every node?

It would be really great if someone can explain me its each step for How to create transaction filters? Where to create? How to process or run that transaction filters?

Please help me with this asap.

peer network with different startingheight value

Sat, 28 Sep 2019 15:43:07 +0000

Dear Team,

I have a network composed by 4 nodes, one seed node and other 3 nodes connected to it. I checked they are in sync with the <getblockchaininfo> command. All of them show the same values for the following parameters:
"blocks" : 477,
"headers" : 477,
"bestblockhash" : "00110f363f98ff344e93d5491b79644783abd2f58a7b257540be7c416596a562"

However, if I log in in the seed node and I send the command <getpeerinfo>, I get the list of the 3 peers with a different value for one of them:
[
{
"id" : 1,
"startingheight" : 462,
"banscore" : 0,
"synced_headers" : 476,
"synced_blocks" : 476,
},
{
"id" : 3,
"startingheight" : 477,
"banscore" : 0,
"synced_headers" : 477,
"synced_blocks" : 477,
},
{
"id" : 4,
"startingheight" : 477,
"banscore" : 0,
"synced_headers" : 477,
"synced_blocks" : 477,
}
]

Could you kindly help me in understanding? Thanks, Fabio

Connect local node to frontend hosted on a server online

Sun, 02 Jun 2019 22:29:28 +0000

I was working running a multichain node and a frontend locally (making request to localhost). Now I want to put the frontend hosted in AWS or another hosting provider, but I don't know, what i've to do to communicate mi multichain node to the online frontend. The idea is communicate the chain node and frontend assuming that aren't neccesary in the same network.
Can you give me advice or information on how to approach this challenge?

debug net - last seen nodes - remove

Mon, 17 Sep 2018 13:17:42 +0000

Follow up question ...This question comes from the related question...

How long until they disapear? I have last seen nodes for over 7000hrs. we have a huge blockchain (over 1,6millon blocks in 9/10 months) and it will keep increasing.

When sycning from scratch it wastes a huge amount of time trying to connect to these "dead" nodes. There should be a way to manully maintain these IPs.

Where are they stored?

There should be also a runtime parameter or a switch in the params.dat to manually maintain dnsseeds.

Thx

Connection not established

Fri, 14 Sep 2018 21:45:34 +0000

This are not nodes in the peerlist ... they seem to be some old nodes that do not exist anymore (I suppose because of dynamic ip). When using -debug=net they show up.

If I try to remove them with addnode, obviuosly it doesnt work, because they are not there.

./multichain-cli testnet1 addnode "12.123.250.15:4566" remove
{"method":"addnode","params":["12.123.250.15:4566","remove"],"id":1,"chain_name":"testnet1"}

error code: -24
error message:
Error: Node has not been added.

In the debug.log i see these old IP's .. how do I remove them? were are they stored?

2018-09-14 21:36:43 net: Trying to connect to 12.123.250.15:4566
2018-09-14 21:36:43 net: trying connection 12.123.250.15:4566 lastseen=3032.3hrs
2018-09-14 21:36:48 net: connection to 12.123.250.15:4566 timeout
2018-09-14 21:36:48 net: Connection not established

How to remove old nodes and prevent to attempt conenction to those old nodes ?

Fri, 14 Sep 2018 17:38:45 +0000

I have a testnet that has been running for several months. We have had several nodes from different locations connected. The blockchain has more than a millon blocks right now. Syncing a node from scratch is not working that well.

After enableing the -debug=net paramter I can see it is trying to connect to very very old nodes that do not exist any more or they had dynamic IPs. How to remove these IP's ?

2018-09-14 17:30:20 net: Trying to connect to xxx.xxx.xxx.xxx:xxxx
2018-09-14 17:30:20 net: trying connection xxx.xxx.xxx.xxx:xxxx lastseen=7365.4hrs
2018-09-14 17:30:25 net: connection to xxx.xxx.xxx.xxx:xxxx timeout
2018-09-14 17:30:25 net: Connection not established

I have way to many of these and the all have thounsands of hours of last seen...

Can't connect two nodes on different networks

Fri, 14 Sep 2018 14:46:38 +0000

I'm creating a chain using multichain-util, setting a username and password in multichain.conf, and then starting the daemon using multichaind chainname -rpcallowip=0.0.0.0/0 -daemon.

I receive the following output:

Starting up node...

Other nodes can connect to this node using:

multichaind chainname@172.20.10.0:7217

Node ready.

When trying to use multichaind chainname@172.20.10.0:7217 -rpcport=7216 -rpcuser=multichainrpc -multichainpass=pass from another computer I receive:

Error: Couldn't connect to the seed node 172.20.10.0 on port 7217 - please check multichaind is running at that address and that your firewall settings allow incoming connections.

I have tried turning firewalls off to no success. I can create two nodes and connect them successfully when they are using the same internet connection, but can't find what the problem is here.

Connecting to docker instance that's running multichain

Sat, 12 May 2018 20:34:22 +0000

So I have a multichain instance running on a centos docker image. My main machine is Windows 10 and I can connect to my multichain node and run commands using the multichain-cli application.

Now I am writing a Java application that uses the MultiChainJavaAPI and I am getting an exception thrown when I try to connect and run any commands. The exception I get is;

MultichainException [
object=code :401,
reason=message : Authorization Required,
message=null,
cause=null
]

I was originally working on an Ubuntu VM, and did not have a problem, but I wasn't running the multichain server on Docker. Now I am running it on windows I am facing this issue.

Here is CLI output from my terminals to show all is working.

Docker Image

[root@e91ecb9e1ebf recordz_chain]# multichaind recordz_chain -daemon

MultiChain 1.0.4 Daemon (latest protocol 10010)

Starting up node...

Other nodes can connect to this node using:
multichaind recordz_chain@172.17.0.3:6471

Listening for API requests on port 6470 (local only - see rpcallowip setting)

Node ready.

Windows Machine

PS C:\Software\multichain-windows-1.0.4> .\multichaind.exe recordz_chain -daemon

MultiChain 1.0.4 Daemon (latest protocol 10010)

Other nodes can connect to this node using:
multichaind recordz_chain@192.168.99.1:6471

This host has multiple IP addresses, so from some networks:
multichaind recordz_chain@192.168.56.1:6471
multichaind recordz_chain@192.168.0.10:6471

Listening for API requests on port 6470 (local only - see rpcallowip setting)

Node ready.

Command From Windows Terminal

PS C:\Software\multichain-windows-1.0.4> .\multichain-cli.exe recordz_chain getinfo

{"method":"getinfo","params":[],"id":1,"chain_name":"recordz_chain"}

{
"version" : "1.0.4",
"nodeversion" : 10004901,
"protocolversion" : 10010,
"chainname" : "recordz_chain",
"description" : "MultiChain recordz_chain",
"protocol" : "multichain",
"port" : 6471,
"setupblocks" : 60,
"nodeaddress" : "recordz_chain@192.168.99.1:6471",
"burnaddress" : "1XXXXXXXLnXXXXXXiTXXXXXXTFXXXXXXWF5mxB",
"incomingpaused" : false,
"miningpaused" : false,
"walletversion" : 60000,
"balance" : 0.00000000,
"walletdbversion" : 2,
"reindex" : false,
"blocks" : 59,
"timeoffset" : 0,
"connections" : 2,
"proxy" : "",
"difficulty" : 0.00000006,
"testnet" : false,
"keypoololdest" : 1526140326,
"keypoolsize" : 2,
"paytxfee" : 0.00000000,
"relayfee" : 0.00000000,
"errors" : ""
}

I have the correct permissions setup and can communicate from my windows machine to my docker image, but when I am trying to run the application I get that error. I would have thought it was an issue with the API I am using, but I had this working before while on my Ubuntu VM, so I know its not the API.

I did find this answer - https://www.multichain.com/qa/2444/running-multichain-docker-unable-connect-external-service

I applied the solution of changing the defaulted password to a shorter one, just 'password' and restarted the multichain server and my windows connection to it. I also updated the password in my java application but still getting the same result.

I'm out of ideas now. Any help would be much appreciated

Redundant connecction

Tue, 17 Apr 2018 12:44:01 +0000

I'm tryng to build a network of computer and multichain based system.

i start first server:

multichaind xyzchain -daemon

answer from server:

Other nodes can connect to this node using:        multichaind xyzchain @1.1.1.1:4765

i go to server number 2, and i connect this server to origin server.

multichaind xyzchain @1.1.1.1:4765

i become answer:

Other nodes can connect to this node using:        multichaind xyzchain@2.2.2.2:4336

i go to server number 3, and i connect this server to origin server.

multichaind xyzchain @1.1.1.1:4765

i become answer:

Other nodes can connect to this node using:        multichaind xyzchain@3.3.3.3:4336

and i can set more and more servers on same system... null problems

at this we have origin server and some "first ring" servers...

then i connect "second ring of servers":

i go to server number 20 , and i connect this server to server number 2.

multichaind xyzchain @2.2.2.2:4336

i become answer:

Other nodes can connect to this node using:        multichaind xyzchain@20.20.20.20:4337

i go to server number 21 , and i connect this server to server number 3.

multichaind xyzchain @3.3.3.3:4336

i become answer:

Other nodes can connect to this node using:        multichaind xyzchain@21.21.21.21:4337

and so on ... null problem

if one of the "first server ring" goes down the connected server also goes down... (example: server number 2 goes down, the server 21 goes also down) .
I try to connect the server 21 to server 2 and the server 20 to server 3. in this manner i can prevent lost connection and/or brocken servers....but if i try to do this vonnection i become: answer i can't do thath connection... node alreaddy connected.

how i can connect: server A to server B & server B to server C & Server C to Server A like a triangle ?????? when i try to made last connection C to A the system answer connection alreaddy exist.

sorry for duplicated explanations.... the question is how i can interconnect a multichain servers for prevent to have isolated service servers.

Regards.

What happens if network connection to other nodes goes down?

Tue, 27 Mar 2018 14:33:09 +0000

What happens to a message if the network connection between this node and other nodes goes down? Does the mutichain server report an error, or does it hold onto the message until the connection is restored? Other nodes may continue to generate messages, perform mining and add to the chain, which means that when the connection comes up again the blockchain at my node is out of step with that used by the other nodes. Does the blockchain get synchronised before my message is added to the end, or is my message lost?

Can this be done? Lightning Network with Multichain? Thanks!

Sun, 25 Feb 2018 17:02:13 +0000

Connecting to a AWS instance of multichain in bitcoin style

Wed, 14 Feb 2018 03:16:34 +0000

Hi Multichain Team

I have installed an multichain instance in amazon AWS (attach params.dat just relevant parameters below) , I have a MSigna wallet used normally for bitcoin , the problem is this wallet doesnt connects to multichain even when I have configured the chain in bitcoin mode , the wallet keeps on trying to connect and only shows connecting but never does it! What can it be? P:D No native assets just native currency requiered.

Thanks in advance

# ==== MultiChain configuration file ====

# Created by multichain-util
# Protocol version: 10009

# This parameter set is VALID.
# To join network please run "multichaind ecupaybeta2".

# The following parameters can only be edited if this file is a prototype of another configuration file.
# Please run "multichain-util clone ecupaybeta2 <new-network-name>" to generate new network.

# Basic chain parameters

chain-protocol = bitcoin                # Chain protocol: multichain (permissions, native assets) or bitcoin
chain-description = MultiChain ecupaybeta # Chain description, embedded in genesis block coinbase, max 90 chars.
root-stream-name = root                 # Root stream name, blank means no root stream.
root-stream-open = true                 # Allow anyone to publish in root stream
chain-is-testnet = false                # Content of the 'testnet' field of API responses, for compatibility.
target-block-time = 15                  # Target time between blocks (transaction confirmation delay), seconds. (2 - 86400)
maximum-block-size = 8388608            # Maximum block size in bytes. (1000 - 1000000000)

# Global permissions

anyone-can-connect = true               # Anyone can connect, i.e. a publicly readable blockchain.
anyone-can-send = true                  # Anyone can send, i.e. transaction signing not restricted by address.
anyone-can-receive = true               # Anyone can receive, i.e. transaction outputs not restricted by address.
anyone-can-receive-empty = true         # Anyone can receive empty output, i.e. without permission grants, asset transfers and zero native currency.
anyone-can-create = false               # Anyone can create new streams.
anyone-can-issue = false                # Anyone can issue new native assets.
anyone-can-mine = true                  # Anyone can mine blocks (confirm transactions).
anyone-can-activate = false             # Anyone can grant or revoke connect, send and receive permissions.
anyone-can-admin = false                # Anyone can grant or revoke all permissions.
support-miner-precheck = true           # Require special metadata output with cached scriptPubKey for input, to support advanced miner checks.
allow-arbitrary-outputs = false         # Allow arbitrary (without clear destination) scripts.
allow-p2sh-outputs = true               # Allow pay-to-scripthash (P2SH) scripts, often used for multisig. Ignored if allow-arbitrary-outputs=true.
allow-multisig-outputs = true           # Allow bare multisignature scripts, rarely used but still supported. Ignored if allow-arbitrary-outputs=true.

# Defaults for node runtime parameters

lock-admin-mine-rounds = 10             # Ignore forks that reverse changes in admin or mine permissions after this many mining rounds have passed. Integer only. (0 - $
mining-requires-peers = true            # Nodes only mine blocks if connected to other nodes (ignored if only one permitted miner).
mine-empty-rounds = 10                  # Mine this many rounds of empty blocks before pausing to wait for new transactions. If negative, continue indefinitely (ignore$
mining-turnover = 0.5                   # Prefer pure round robin between a subset of active miners to minimize forks (0.0) or random equal participation for all permi$

# Native blockchain currency (likely not required)

initial-block-reward = 1000000          # Initial block mining reward in raw native currency units. (0 - 1000000000000000000)
first-block-reward = -1                 # Different mining reward for first block only, ignored if negative. (-1 - 1000000000000000000)
reward-halving-interval = 52560000      # Interval for halving of mining rewards, in blocks. (60 - 1000000000)
reward-spendable-delay = 1              # Delay before mining reward can be spent, in blocks. (1 - 100000)
minimum-per-output = 0                  # Minimum native currency per output (anti-dust), in raw units.
                                        # If set to -1, this is calculated from minimum-relay-fee. (-1 - 1000000000)
maximum-per-output = 100000000000000    # Maximum native currency per output, in raw units. (0 - 1000000000000000000)
minimum-relay-fee = 0                   # Minimum transaction fee, per 1000 bytes, in raw units of native currency. (0 - 1000000000)
native-currency-multiple = 10           # Number of raw units of native currency per display unit. (0 - 1000000000)

only-accept-std-txs = true              # Only accept and relay transactions which qualify as 'standard'.
max-std-tx-size = 4194304               # Maximum size of standard transactions, in bytes. (1024 - 100000000)
max-std-op-returns-count = 10           # Maximum number of OP_RETURN metadata outputs in standard transactions. (0 - 1024)
max-std-op-return-size = 2097152        # Maximum size of OP_RETURN metadata in standard transactions, in bytes. (0 - 67108864)
max-std-op-drops-count = 5              # Maximum number of OP_DROPs per output in standard transactions. (0 - 100)
max-std-element-size = 8192             # Maximum size of data elements in standard transactions, in bytes. (128 - 32768)
# The following parameters were generated by multichain-util.
# They SHOULD ONLY BE EDITED IF YOU KNOW WHAT YOU ARE DOING.

default-network-port = 8300             # Default TCP/IP port for peer-to-peer connection with other nodes.
default-rpc-port = 2654                 # Default TCP/IP port for incoming JSON-RPC API requests.
chain-name = ecupaybeta2                # Chain name, used as first argument for multichaind and multichain-cli.
protocol-version = 10009                # Protocol version at the moment of blockchain genesis.
network-message-start = f9beb4d9        # Magic value sent as the first 4 bytes of every peer-to-peer message.
address-pubkeyhash-version = 00         # Version bytes used for pay-to-pubkeyhash addresses.
address-scripthash-version = 05         # Version bytes used for pay-to-scripthash addresses.
private-key-version = 80                # Version bytes used for exporting private keys.
address-checksum-value = 00000000       # Bytes used for XOR in address checksum calculation.

Using initprivkey

Wed, 06 Sep 2017 09:38:00 +0000

Hi

I have a node (say, node1) running on a specific network and rpc port (7333, 7332). I generated a new address and granted it connect, send, receive permissions.

Then, did "dumpprivkey my_address" to get the corresponding private key.

I tried to connect to this chain by starting another node (say, node2) on a different network and rpc ports, and this was my command

"multichaind testchain1@10.0.2.15:7333 -datadir=~/.multichain-other-5 -port=10333 -rpcport=10332 initprivkey=V8odv8EBR6F91qGfNZdsHiWXqmiZLJH1TGWmQyHGbtQSyWH1u6E21twv -daemon

The input to initprivkey was exactly the same as the output of dumpprivkey on node1. Still this second node generates a new random address. Am I sending the argument incorrectly or doing something else wrongly?

Connecting AWS Lambda to Blockchain.

Mon, 31 Jul 2017 18:41:16 +0000

I have my blockchain in an EC2 instance. I have an AWS lambda function that I want to add an item to a stream. I keep getting this error: "Error: connect ECONNREFUSED".

How do I allow the Lambda IP to access my blockchain?

connect the chain created on aws to the local system

Wed, 12 Jul 2017 09:44:59 +0000

I have created a chain on my AWS instance:

multichain-util create chain1 -datadir="node1"

then, changed the default-network-port to 8080 and rpc-port to 8000 in params.dat file

Started the chain :

sudo multichaind chain1 -datadir="node1" -daemon

I got a command to connect to it:

multichaind chain1@XXX.XX.XX.XXX:8080

Run the above command in local system and got error message like:

"Error: Couldn't connect to the seed node XXX.XX.XX.XXX on port 8080 - please check multichaind is running at that address and that your firewall settings allow incoming connections."

Note: Vice-versa is connecting successfully.

Anyone knows how to fix it?

Hello everybody :), I have 2 PC connected in Local Area Network. How can i send documents using Multichain.

Thu, 11 May 2017 15:40:56 +0000

How to send a document between 2 PC in LAN ?

- Linux (CentOs)

- Using a switch with RJ45.

I want to push just a PDF on the blockchain.

Thanks :)

Multichain & Docker: peer discovery not working

Thu, 23 Mar 2017 20:33:50 +0000

Hi.

Is it possible to tell Multichain what ip and port it should exchange as endpoint information to other nodes?

The peer discovery and exchange does not work when running inside a docker container since it seems that the nodes exchange the wrong ip address and port that is not accessible form outside the container because the container ip != public ip and the container p2p port != the external mapped p2p port.

I can connect nodes manually but it seems they cannot share node information to get fully connected.

What is the parameter -externalip for example?

Greetings,

Alex

Multichaind seed node couldn't connect from 1.0 alpha 22

Fri, 27 Jan 2017 22:01:32 +0000

Using the same two nodes I repeated the "Create a MultiChain private blockchain in 90 seconds" till 1.0-alpha-21.

From 1.0-alpha-22 I get an error such this:

Error: Couldn't connect to the seed node 10.10.20.90 on port 6737 - please check multichaind is running at that address and that your firewall settings allow incoming connections.

My nodes are two clones of LXC container with the following kernel:

root@multichain-01:~/multichain-1.0-alpha-22# uname -a
Linux multichain-01 3.16.0-4-amd64 #1 SMP Debian 3.16.36-1+deb8u2 (2016-10-19) x86_64 GNU/Linux

Is there something to change in configuration from alpha-22 ?

Regards,

Data exchange between two private blockchains

Thu, 12 Jan 2017 10:22:03 +0000

I have two private blockchains from different users/systems within multichain. Now I will transfer data between the systems. System 1 asks for specific information from System 2 and System 2 will provide the required data. I thought that I could use streams for this scenario. But if the streams stored within the blockchain how I could transfer the data to another blockchain within multichain? My question in another way: How can I transfer data between two chains?

What is the architecture behind this concept?

Wed, 11 Jan 2017 15:46:32 +0000

If I will use a stream, what is the architecture behind this concept? System A deals with chain 1, and system B deals with chain 2. I think the concept looks like this: I have two systems. Each system contains several Multichain-Nodes (=machines). Each Multichain-Node provides a private blockchain. But where is the stream located? Each Multichain-Node have to provide the stream (like the private blockchain) or is the stream on another machine located (the stream exists only once)?

What is the right concept?

Connect two chains

Tue, 10 Jan 2017 10:46:48 +0000

I have one chain (chain1) in one system (system A) and another different chain (chain2) in another system (system B). I need to connect this both chains, ie., i need to catch details of chain1 from chain2 and vice versa. Is this possible?

Couldn't connect to the seed node error on Ubuntu AWS EC2

Fri, 16 Dec 2016 14:35:23 +0000

I have set up two Ubuntu instances on Amazon AWS EC2. I can ssh from one to the other.

However following the getting started documentation, I cannot connect from one server to the other one.

I have checked that `multichaind` is running and that the ports are open. Issuing `sudo netstat -ntlp | grep LISTEN` yields:

tcp 0 0 127.0.0.1:7216 0.0.0.0:* LISTEN 3241/multichaind
tcp 0 0 0.0.0.0:7217 0.0.0.0:* LISTEN 3241/multichaind
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1166/sshd
tcp6 0 0 ::1:7216 :::* LISTEN 3241/multichaind
tcp6 0 0 :::7217 :::* LISTEN 3241/multichaind
tcp6 0 0 :::22 :::* LISTEN 1166/sshd

Still: When trying `multichaind chain1@<ipAddress>:7217` I get the typical error message:

Error: Couldn't connect to the seed node <ipAddress> on port 7217 - please check multichaind is running at that address and that your firewall settings allow incoming connections.

Any thoughts?

Error: Couldn't connect to the seed node

Tue, 01 Nov 2016 08:18:33 +0000

Hi all,

Sorry to bother you with a question that has been asked 781235 times already: the impossibility to connect to seed node (Error: Couldn't connect to the seed node 10.0.2.15 on port 6819 - please check multichaind is running at that address and that your firewall settings allow incoming connections.). I've seen multiple threads but I couldn't solve my problem after countless hours browsing the web, that's why I'm here. We need to use this for a class and my fellow students couldn't connect either.

I had one idea for the origin of the bug: the ip of the seed node is not the same as what we set in the Vagrantfile.

I installed multichain on my computer (Ubuntu 16.04 LTS) and would like to have 3 VMs talking to each other. One VM would create a blockchain and the other two would interact with it.

The Vagrantfile I used is the following (provided by my professor):

# -*- mode: ruby -*-
# vi: set ft=ruby :

Vagrant.require_version ">= 1.6.2"

Vagrant.configure(2) do |config|

  config.vm.box = "ubuntu/trusty64"
  # config.vm.box = "https://cloud-images.ubuntu.com/vagrant/wily/current/wily-server-cloudimg-amd64-vagrant-disk1.box"

  # config.vm.hostname = "Multichain"
  # config.vm.network :private_network, :ip => '10.4.4.4'
  number_of_nodes = 3
  number_of_nodes.times do |i|
    config.vm.define "multichain-node-#{i}" do |node|
      node.vm.hostname = "multichain-node-#{i}"
      node.vm.network :private_network, :ip => "10.4.4.#{i}"
      node.vm.provider :virtualbox do |vb|
        #vb.gui = true
        vb.customize ["modifyvm", :id, "--memory", "512"]
        vb.customize ["modifyvm", :id, "--natdnshostresolver1", "off"]
        vb.customize ["modifyvm", :id, "--natdnsproxy1", "off"]
        vb.name = "MultiChain-#{i}"
      end
    end
    i += 1
  end

  config.ssh.forward_agent = true
  config.ssh.forward_x11 = true

  config.vm.provision "shell", :inline => "wget http://www.multichain.com/download/multichain-1.0-alpha-16.tar.gz"
  config.vm.provision "shell", :inline => "tar -xvzf multichain-1.0-alpha-16.tar.gz"
  config.vm.provision "shell", :inline => "cd multichain-1.0-alpha-16 && mv multichaind multichain-cli multichain-util /usr/local/bin"

end

Then I run:

$ vagrant up
$ vagrant ssh multichain-node-0
Welcome to Ubuntu 14.04.5 LTS (GNU/Linux 3.13.0-100-generic x86_64)

 * Documentation:  https://help.ubuntu.com/

 System information disabled due to load higher than 1.0

  Get cloud support with Ubuntu Advantage Cloud Guest:
    http://www.ubuntu.com/business/services/cloud

0 packages can be updated.
0 updates are security updates.

New release '16.04.1 LTS' available.
Run 'do-release-upgrade' to upgrade to it.

/usr/bin/xauth:  file /home/vagrant/.Xauthority does not exist

Following the example on https://github.com/oschain/multichain/blob/master/README.md , in multichain-node-0 I run:

vagrant@multichain-node-1:~$ multichain-util create lamchain
MultiChain utilities build 1.0 alpha 16 protocol 10003

Blockchain parameter set was successfully generated.
You can edit it in /home/vagrant/.multichain/lamchain/params.dat before running multichaind for the first time.

To generate blockchain please run "multichaind lamchain".


vagrant@multichain-node-1:~$ multichaind lamchain -daemon  -debug=mchn -debug=mchnminor -debug=net

MultiChain Core Daemon build 1.0 alpha 16 protocol 10003

Multichain server starting
vagrant@multichain-node-1:~$ Looking for genesis block...
Genesis block found
New users can connect to this node using
multichaind lamchain@10.0.2.15:6819

Node started

Now I open a new tab in my terminal (Ctrl + Alt + t) and connect to the second node using on my machine (terminal of my Ubuntu, not a VM):

$ vagrant ssh multichain-node-1
Welcome to Ubuntu 14.04.5 LTS (GNU/Linux 3.13.0-100-generic x86_64)

 * Documentation:  https://help.ubuntu.com/

 System information disabled due to load higher than 1.0

  Get cloud support with Ubuntu Advantage Cloud Guest:
    http://www.ubuntu.com/business/services/cloud

0 packages can be updated.
0 updates are security updates.

New release '16.04.1 LTS' available.
Run 'do-release-upgrade' to upgrade to it.

/usr/bin/xauth:  file /home/vagrant/.Xauthority does not exist
vagrant@multichain-node-2:~$

Now, on the second node I want to connect to the blockchain, using:

vagrant@multichain-node-2:~$ multichaind lamchain@10.0.2.15:6819 -debug=mchn -debug=mchnminor -debug=net

MultiChain Core Daemon build 1.0 alpha 16 protocol 10003

Retrieving blockchain parameters from the seed node 10.0.2.15:6819 ...
Error: Couldn't connect to the seed node 10.0.2.15 on port 6819 - please c

heck multichaind is running at that address and that your firewall settings

 allow incoming connections.

My guess is that there's a problem because it connects on node 10.0.2.15 and not 10.4.4.1 as we set in the Vagrantfile?

If I run ip a I get:

vagrant@multichain-node-1:~$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 08:00:27:24:94:c4 brd ff:ff:ff:ff:ff:ff
    inet 10.0.2.15/24 brd 10.0.2.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::a00:27ff:fe24:94c4/64 scope link 
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 08:00:27:60:10:bf brd ff:ff:ff:ff:ff:ff
    inet 10.4.4.1/24 brd 10.4.4.255 scope global eth1
       valid_lft forever preferred_lft forever
    inet6 fe80::a00:27ff:fe60:10bf/64 scope link 
       valid_lft forever preferred_lft forever

And :

vagrant@multichain-node-2:~$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 08:00:27:24:94:c4 brd ff:ff:ff:ff:ff:ff
    inet 10.0.2.15/24 brd 10.0.2.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::a00:27ff:fe24:94c4/64 scope link 
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 08:00:27:39:f3:4e brd ff:ff:ff:ff:ff:ff
    inet 10.4.4.2/24 brd 10.4.4.255 scope global eth1
       valid_lft forever preferred_lft forever
    inet6 fe80::a00:27ff:fe39:f34e/64 scope link 
       valid_lft forever preferred_lft forever

It is probably useful to know also that my internet connection is under my school's firewall.

Thanks A LOT even if you don't answer but took the time to read until here, it's still very nice of you! By helping me you might end up solving a problem for lots of students :)

Network throughput computation

Thu, 27 Oct 2016 19:53:40 +0000

Hi,

I am interested in how the general network throughput of multichain can be computed (how you guys did it in "http://www.multichain.com/blog/2016/07/announcing-the-new-multichain-wallet/" quoting 200 to 800 tx/sec).

Thanks

R.

Nodes with different timezones

Sun, 27 Mar 2016 01:17:20 +0000

Hi,

I have been testing a MultiChain private setup across some docker clusters and I have noticed that there is no compensation for nodes with different timezone settings. For instance, I have the majority of nodes set to BST but one that is set to UTC throws errors when receiving blocks/transactions. Both nodes have the right time as far as their timezone is concerned, but it seems that the communication is not taking this into account between nodes. I therefore see a lot of "Time is too far in the future" errors. Is this behaviour correct? If so, then how is does BitCoin work across multiple geographical areas?