btcd/docs/configuration.md

Configuration

btcd has a number of configuration options, which can be viewed by running: $ btcd --help.

Peer server listen interface

btcd allows you to bind to specific interfaces which enables you to setup configurations with varying levels of complexity. The listen parameter can be specified on the command line as shown below with the -- prefix or in the configuration file without the -- prefix (as can all long command line options). The configuration file takes one entry per line.

NOTE: The listen flag can be specified multiple times to listen on multiple interfaces as a couple of the examples below illustrate.

Command Line Examples:

Flags	Comment
--listen=	all interfaces on default port which is changed by --testnet and --regtest (default)
--listen=0.0.0.0	all IPv4 interfaces on default port which is changed by --testnet and --regtest
--listen=::	all IPv6 interfaces on default port which is changed by --testnet and --regtest
--listen=:8333	all interfaces on port 8333
--listen=0.0.0.0:8333	all IPv4 interfaces on port 8333
--listen=[::]:8333	all IPv6 interfaces on port 8333
--listen=127.0.0.1:8333	only IPv4 localhost on port 8333
--listen=[::1]:8333	only IPv6 localhost on port 8333
--listen=:8336	all interfaces on non-standard port 8336
--listen=0.0.0.0:8336	all IPv4 interfaces on non-standard port 8336
--listen=[::]:8336	all IPv6 interfaces on non-standard port 8336
--listen=127.0.0.1:8337 --listen=[::1]:8333	IPv4 localhost on port 8337 and IPv6 localhost on port 8333
--listen=:8333 --listen=:8337	all interfaces on ports 8333 and 8337

The following config file would configure btcd to only listen on localhost for both IPv4 and IPv6:

[Application Options]

listen=127.0.0.1:8333
listen=[::1]:8333

In addition, if you are starting btcd with TLS and want to make it available via a hostname, then you will need to generate the TLS certificates for that host. For example,

gencerts --host=myhostname.example.com --directory=/home/me/.btcd/

RPC server listen interface

btcd allows you to bind the RPC server to specific interfaces which enables you to setup configurations with varying levels of complexity. The rpclisten parameter can be specified on the command line as shown below with the -- prefix or in the configuration file without the -- prefix (as can all long command line options). The configuration file takes one entry per line.

A few things to note regarding the RPC server:

• The RPC server will not be enabled unless the rpcuser and rpcpass options are specified.
• When the rpcuser and rpcpass and/or rpclimituser and rpclimitpass options are specified, the RPC server will only listen on localhost IPv4 and IPv6 interfaces by default. You will need to override the RPC listen interfaces to include external interfaces if you want to connect from a remote machine.
• The RPC server has TLS enabled by default, even for localhost. You may use the --notls option to disable it, but only when all listeners are on localhost interfaces.
• The --rpclisten flag can be specified multiple times to listen on multiple interfaces as a couple of the examples below illustrate.
• The RPC server is disabled by default when using the --regtest and --simnet networks. You can override this by specifying listen interfaces.

Command Line Examples:

Flags	Comment
--rpclisten=	all interfaces on default port which is changed by --testnet
--rpclisten=0.0.0.0	all IPv4 interfaces on default port which is changed by --testnet
--rpclisten=::	all IPv6 interfaces on default port which is changed by --testnet
--rpclisten=:8334	all interfaces on port 8334
--rpclisten=0.0.0.0:8334	all IPv4 interfaces on port 8334
--rpclisten=[::]:8334	all IPv6 interfaces on port 8334
--rpclisten=127.0.0.1:8334	only IPv4 localhost on port 8334
--rpclisten=[::1]:8334	only IPv6 localhost on port 8334
--rpclisten=:8336	all interfaces on non-standard port 8336
--rpclisten=0.0.0.0:8336	all IPv4 interfaces on non-standard port 8336
--rpclisten=[::]:8336	all IPv6 interfaces on non-standard port 8336
--rpclisten=127.0.0.1:8337 --listen=[::1]:8334	IPv4 localhost on port 8337 and IPv6 localhost on port 8334
--rpclisten=:8334 --listen=:8337	all interfaces on ports 8334 and 8337

The following config file would configure the btcd RPC server to listen to all interfaces on the default port, including external interfaces, for both IPv4 and IPv6:

[Application Options]

rpclisten=

Default ports

While btcd is highly configurable when it comes to the network configuration, the following is intended to be a quick reference for the default ports used so port forwarding can be configured as required.

btcd provides a --upnp flag which can be used to automatically map the bitcoin peer-to-peer listening port if your router supports UPnP. If your router does not support UPnP, or you don't wish to use it, please note that only the bitcoin peer-to-peer port should be forwarded unless you specifically want to allow RPC access to your btcd from external sources such as in more advanced network configurations.

Name	Port
Default Bitcoin peer-to-peer port	TCP 8333
Default RPC port	TCP 8334

Using bootstrap.dat

What is bootstrap.dat?

It is a flat, binary file containing bitcoin blockchain data starting from the genesis block and continuing through a relatively recent block height depending on the last time it was updated.

See this thread on bitcointalk for more details.

NOTE: Using bootstrap.dat is entirely optional. Btcd will download the block chain from other peers through the Bitcoin protocol with no extra configuration needed.

What are the pros and cons of using bootstrap.dat?

Pros:

• Typically accelerates the initial process of bringing up a new node as it downloads from public P2P nodes and generally is able to achieve faster download speeds
• It is particularly beneficial when bringing up multiple nodes as you only need to download the data once

Cons:

• Requires you to setup and configure a torrent client if you don't already have one available
• Requires roughly twice as much disk space since you'll need the flat file as well as the imported database

Where do I get bootstrap.dat?

The bootstrap.dat file is made available via a torrent. See this thread on bitcointalk for the torrent download details.

How do I know I can trust the bootstrap.dat I downloaded?

You don't need to trust the file as the addblock utility verifies every block using the same rules that are used when downloading the block chain normally through the Bitcoin protocol. Additionally, the chain rules contain hard-coded checkpoints for the known-good block chain at periodic intervals. This ensures that not only is it a valid chain, but it is the same chain that everyone else is using.

How do I use bootstrap.dat with btcd?

btcd comes with a separate utility named addblock which can be used to import bootstrap.dat. This approach is used since the import is a one-time operation and we prefer to keep the daemon itself as lightweight as possible.

1. Stop btcd if it is already running. This is required since addblock needs to access the database used by btcd and it will be locked if btcd is using it.
2. Note the path to the downloaded bootstrap.dat file.
3. Run the addblock utility with the -i argument pointing to the location of boostrap.dat:

Windows:

"%PROGRAMFILES%\Btcd Suite\Btcd\addblock" -i C:\Path\To\bootstrap.dat

Linux/Unix/BSD/POSIX:

$GOPATH/bin/addblock -i /path/to/bootstrap.dat