Running A Full Node - Bitcoin - The first knowledge sharing application in Vietnam

What Is A Full Node?

A full node is a program that fully validates transactions and blocks.
Almost all full nodes also help the network by accepting transactions
and blocks from other full nodes, validating those transactions and
blocks, and then relaying them to further full nodes.

Most full nodes also serve lightweight clients by allowing them to
transmit their transactions to the network and by notifying them when a
transaction affects their wallet. If not enough nodes perform this
function, clients won’t be able to connect through the peer-to-peer
network—they’ll have to use centralized services instead.

Many people and organizations volunteer to run full nodes using spare
computing and bandwidth resources—but more volunteers are needed to
allow Bitcoin to continue to grow. This document describes how you can
help and what helping will cost you.

Setup a Full Node

Costs And Warnings

Running a Bitcoin full node comes with certain costs and can expose you
to certain risks. This section will explain those costs and risks so you
can decide whether you’re able to help the network.

Special Cases

Miners, businesses, and privacy-conscious users rely on particular
behavior from the full nodes they use, so they will often run their own
full nodes and take special safety precautions. This document does not
cover those precautions—it only describes running a full node to help
support the Bitcoin network in general.

Please seek out assistance in the community if you need help
setting up your full node correctly to handle high-value and privacy-sensitive
tasks. Do your own diligence to ensure who you get help from is ethical,
reputable and qualified to assist you.

Secure Your Wallet

It’s possible and safe to run a full node to support the network and use
its wallet to store your bitcoins, but you must take the same
precautions you would when using any Bitcoin wallet. Please see the
securing your wallet page for more
information.

Minimum Requirements

Bitcoin Core full nodes have certain requirements. If you try running a
node on weak hardware, it may work—but you’ll likely spend more time
dealing with issues. If you can meet the following requirements, you’ll
have an easy-to-use node.

Desktop or laptop hardware running recent versions of Windows, Mac OS
X, or Linux.
7 gigabytes of free disk space,
accessible at a minimum read/write speed of 100 MB/s.
2 gigabytes of memory (RAM)
A broadband Internet connection with upload speeds of at least 400
kilobits (50 kilobytes) per second
An unmetered connection, a connection with high upload limits, or a
connection you regularly monitor to ensure it doesn’t exceed its
upload limits. It’s common for full nodes on high-speed connections to
use 200 gigabytes upload or more a month. Download usage is around 20
gigabytes a month, plus around an additional 340 gigabytes the first
time you start your node.
6 hours a day that your full node can be left running. (You can do
other things with your computer while running a full node.)
More hours would be better, and best of all would be if you can run
your node continuously.

Note: many operating systems today (Windows, Mac, and Linux) enter a
low-power mode after the screensaver activates, slowing or halting
network traffic. This is often the default setting on laptops and on
all Mac OS X laptops and desktops. Check your screensaver settings
and disable automatic “sleep” or “suspend” options to ensure you
support the network whenever your computer is running.

Possible Problems

Legal: Bitcoin use is prohibited or restricted in some
areas.
Bandwidth limits: Some Internet plans will charge an additional
amount for any excess upload bandwidth used that isn’t included in
the plan. Worse, some providers may terminate your connection without
warning because of overuse. We advise that you check whether your
Internet connection is subjected to such limitations and monitor your
bandwidth use so that you can stop Bitcoin Core before you reach your
upload limit.
Anti-virus: Several people have placed parts of known computer
viruses in the Bitcoin block chain. This block chain data can’t infect
your computer, but some anti-virus programs quarantine the data
anyway, making it more difficult to run Bitcoin Core. This problem mostly
affects computers running Windows.
Attack target: Bitcoin Core powers the Bitcoin peer-to-peer
network, so people who want to disrupt the network may
attack Bitcoin Core users in ways that will affect other things
you do with your computer, such as an attack that limits your
available download bandwidth.

Initial Block Download(IBD)

Initial block download
refers to the process where nodes synchronize themselves
to the network by downloading blocks that are new to them.
This will happen when a node is far behind the tip of the best block chain.
In the process of IBD, a node does not accept incoming transactions nor request mempool transactions.

If you are trying to set up a new node following the instructions below, you will go
through the IBD process at the first run, and it may take a considerable amount of time since a new
node has to download the entire block chain (which is roughly 340 gigabytes now).
During the download, there could be a high usage for the network and CPU
(since the node has to verify the blocks downloaded), and the client will take up an
increasing amount of storage space (reduce storage provides more details on reducing storage).

Before the node finishes IBD, you will not be able to see a new transaction related to your account until
the client has caught up to the block containing that transaction.
So your wallet may not count new payments/spendings into the balance.

If you are using Bitcoin Core GUI, you can monitor the progress of IBD in the status bar (left bottom corner).

Bitcoin-Qt Initial Block Download

Linux Instructions

The following instructions describe installing Bitcoin Core using tools
available in most mainstream Linux distributions. We assume you use a
Bourne-like shell such as bash.

Using any computer, go to the Bitcoin Core download page
and verify you have made a secure connection to the server.

Verify secure connection

In the “Linux (tgz)” section of the Download page, choose the
appropriate file for your Linux install (either 32-bit or 64-bit) and
download the file. If necessary, move the file to the computer you want
to use to run Bitcoin Core.

Optional: Verify the release signatures

If you know how to use PGP, you should also click the Verify Release
Signatures link on the download page to download a signed list of SHA256
file hashes. The 0.11 and later releases are signed by Wladimir J. van
der Laan’s releases key with the fingerprint:

01EA 5486 DE18 A882 D4C2  6845 90C8 019E 36C2 E964

Earlier releases were signed by Wladimir J. van der Laan’s regular
key. That key’s fingerprint is:

71A3 B167 3540 5025 D447  E8F2 7481 0B01 2346 C9A6

Even earlier releases were signed by Gavin Andresen’s
key. His primary key’s fingerprint is:

2664 6D99 CBAE C9B8 1982  EF60 29D9 EE6B 1FC7 30C1

You should verify these keys belong to their owners using the web of
trust or other trustworthy means. Then use PGP to verify the signature
on the release signatures file. Finally, use PGP or another utility to
compute the SHA256 hash of the archive you downloaded, and ensure the
computed hash matches the hash listed in the verified release
signatures file.

If you aren’t already logged into the computer you want to install
Bitcoin on, login now. Make sure you use an account that can use su
or sudo to install software into directories owned by the root user.

If you logged in graphically, start a terminal. If you logged in
another way, we will assume you’re already in a shell.

Locate the file you downloaded and extract it using the tar command
followed by the argument xzf followed by the file name. The argument
xzf means eXtract the gZipped tar archive File. For example, for a
64-bit tar archive in your current directory, the command is:

tar xzf bitcoin-22.0-x86_64-linux-gnu.tar.gz

This will create the directory bitcoin-22.0 within your current
working directory. We will install the contents of its bin
subdirectory into the /usr/local/bin directory using the the install
command. The install command is part of the GNU coreutils available on
nearly every Linux distribution, and the /usr/local/bin directory is a
standard location for self-installed executables (you may edit the
commands below to use a different location).

If you use sudo to run commands as root, use the following command
line:

sudo install -m 0755 -o root -g root -t /usr/local/bin bitcoin-22.0/bin/*

If you use su to run commands as root, use the following command line:

su -c 'install -m 0755 -o root -g root -t /usr/local/bin bitcoin-22.0/bin/*'

To continue, choose one of the following options

To use Bitcoin Core Graphical User Interface (GUI), proceed to the
Bitcoin Core GUI section below.
To use the Bitcoin Core daemon (bitcoind), which is useful for
programmers and advanced users, proceed to the Bitcoin Core
Daemon section below.
To use both the GUI and the daemon, read both the GUI
instructions and the daemon
instructions. Note that you can’t run both the
GUI and the daemon at the same time using the same configuration
directory.

Bitcoin Core GUI

In order to use Bitcoin Core GUI, you will need several libraries
installed. All of them should be available in all major
recently-released Linux distributions, but they may not be installed on
your computer yet. To determine whether you’re missing any libraries,
open a terminal (if you haven’t already) and run the command
/usr/local/bin/bitcoin-qt to start Bitcoin Core GUI.

If all the required libraries are installed, Bitcoin Core will start.
If a required library is missing, an error message similar to the
following message will be displayed:

/usr/local/bin/bitcoin-qt: error while loading shared libraries: libQtGui.so.4: cannot open shared object file: No such file or directory

Search your distribution’s package database for the missing file
missing and install package containing that file. Then re-run
/usr/local/bin/bitcoin-qt to see if it’s missing another file.
Repeat until Bitcoin Core GUI starts.

You will be prompted to choose a directory to store the Bitcoin block
chain and your wallet. Unless you have a separate partition or drive
you want to use, click Ok to use the default.

Bitcoin-Qt Welcome

Bitcoin Core GUI will begin to download the block chain. This step will take at
least several days, and it may take much more time on a slow Internet connection
or with a slow computer. During the download, Bitcoin Core will use a
significant part of your connection bandwidth. You can stop Bitcoin Core at any
time by closing it; it will resume from the point where it stopped the next time
you start it.

Bitcoin-Qt Initial Block Download

After download is complete, you may use Bitcoin Core as your wallet or
you can just let it run to help support the Bitcoin network.

Optional: Start Your Node At Login

Starting your node automatically each time you login to your computer
makes it easy for you to contribute to the network. The easiest way to
do this is to tell Bitcoin Core GUI to start at login. This only works
in desktop environments that support the autostart
specification,
such as Gnome, KDE, and Unity.

While running Bitcoin Core GUI, open the Settings menu and choose
Options. On the Main tab, click Start Bitcoin on system login. Click
the Ok button to save the new settings.

Choosing to start Bitcoin Core at login

The next time you login to your desktop, Bitcoin Core GUI should be
automatically started as an icon in the tray.

If Bitcoin Core GUI does not automatically start, you may need to add it
to an .xinit or .xsession file as described
here.

You have now completed installing Bitcoin Core. If you have any questions, please ask in one of Bitcoin’s many communities, such as Bitcoin StackExchange, BitcoinTalk technical support, or the #bitcoin IRC chatroom on Freenode.

To support the Bitcoin network, you also need to allow incoming
connections. Please read the Network
Configuration section for details.

Bitcoin Core Daemon

If you’re logged in as an administrative user with sudo access, you may
log out. The steps in this section should be performed as the user you
want to run Bitcoin Core. (This can be a locked account used only by
Bitcoin Core.) If you changed users in a graphical interface, start a
terminal.

Type the following command:

bitcoind -daemon

It will print a message that Bitcoin Core is starting. To interact with
Bitcoin Core daemon, you will use the command bitcoin-cli (Bitcoin
command line interface).

Note: it may take up to several minutes for Bitcoin Core to start,
during which it will display the following message whenever you use
bitcoin-cli:

error: {"code":-28,"message":"Verifying blocks..."}

After it starts, you may find the following commands useful for basic
interaction with your node:
getblockchaininfo,
getnetworkinfo,
getnettotals,
getwalletinfo,
stop, and help.

For example, to safely stop your node, run the following command:

bitcoin-cli stop

A complete list of commands is available in the Bitcoin.org developer
reference.

When Bitcoin Core daemon first starts, it will begin to download the block
chain. This step will take at least several days, and it may take much more time
on a slow Internet connection or with a slow computer. During the download,
Bitcoin Core will use a significant part of your connection bandwidth. You can
stop Bitcoin Core at any time using the stop command; it will resume from the
point where it stopped the next time you start it.

Optional: Start Your Node At Boot

Starting your node automatically each time your computer boots makes it
easy for you to contribute to the network. The easiest way to do this
is to start Bitcoin Core daemon from your crontab. To edit your
crontab on most distributions, run the following command:

crontab -e

Scroll to the bottom of the file displayed and add the following line:

@reboot bitcoind -daemon

Save the file and exit; the updated crontab file will be installed for
you. On most distributions, this will cause Bitcoin Core daemon to be
automatically started each time you reboot your computer.

If you’re a expert system administrator and want to use an init script instead, see
the init scripts directory in Bitcoin Core’s source tree.

To support the Bitcoin network, you also need to allow incoming
connections. Please read the Network
Configuration section for details.

Mac OS X Instructions

Mac OS X Yosemite 10.10.x+

Go to the Bitcoin Core download page and verify you have
made a secure connection to the server.

Verify secure connection

Click the large blue Download Bitcoin Core button to download the
Bitcoin Core installer to your Downloads folder.

Optional: Verify the release signatures

01EA 5486 DE18 A882 D4C2  6845 90C8 019E 36C2 E964

Earlier releases were signed by Wladimir J. van der Laan’s regular
key. That key’s fingerprint is:

71A3 B167 3540 5025 D447  E8F2 7481 0B01 2346 C9A6

Even earlier releases were signed by Gavin Andresen’s
key. His primary key’s fingerprint is:

2664 6D99 CBAE C9B8 1982  EF60 29D9 EE6B 1FC7 30C1

After downloading the file to your Downloads folder
(/Users/<YOUR USER NAME>/Downloads), run it by double-clicking
its icon. OS X will open a Finder window for you to drag Bitcoin Core to your
Applications folder.

Window to install

Bitcoin Core GUI

The first time running Bitcoin Core, Max OS X will ask you to confirm that
you want to run it:

Mac OS X File Security Dialog

You will be prompted to choose a directory to store the Bitcoin block
chain and your wallet. Unless you have a separate partition or drive
you want to use, click Ok to use the default.

Bitcoin Core Welcome

Bitcoin Core Initial Block Download

After download is complete, you may use Bitcoin Core as your wallet or
you can just let it run to help support the Bitcoin network.

Optional: Start Your Node At Login

Starting your node automatically each time you login to your computer
makes it easy for you to contribute to the network. The easiest way
to do this is to tell Bitcoin Core GUI to start at login.

While running Bitcoin Core GUI, open the Bitcoin Core menu and choose
Preferences. On the Main tab, click Start Bitcoin on system login. Click
the Ok button to save the new settings.

Choosing to start Bitcoin Core at login

The next time you login to your desktop, Bitcoin Core GUI will be
automatically started minimized in the task bar.

To support the Bitcoin network, you also need to allow incoming
connections. Please read the Network
Configuration section for details.

Bitcoin Core Daemon

The Bitcoin Core daemon (bitcoind) is not included in the .dmg file you may have downloaded to install Bitcoin-QT. Bitcoind, along with its support binaries, is instead included in the OS X .tar.gz file listed on the official Bitcoin Core download page. To download this file using Terminal, execute the following command:

curl -O https://bitcoin.org/bin/bitcoin-core-22.0/bitcoin-22.0-osx64.tar.gz

Optional: Verify the release signatures

01EA 5486 DE18 A882 D4C2  6845 90C8 019E 36C2 E964

Earlier releases were signed by Wladimir J. van der Laan’s regular
key. That key’s fingerprint is:

71A3 B167 3540 5025 D447  E8F2 7481 0B01 2346 C9A6

Even earlier releases were signed by Gavin Andresen’s
key. His primary key’s fingerprint is:

2664 6D99 CBAE C9B8 1982  EF60 29D9 EE6B 1FC7 30C1

Extract bitcoind and its support binaries from the archive we just downloaded by running this command in Terminal:

tar -zxf bitcoin-22.0-osx64.tar.gz

Now we’ll move the executables into your default path to make running and stopping bitcoind easier. To move the executables, run these commands (note that we have to use sudo to perform these commands since we are modifying directories owned by root):

sudo mkdir -p /usr/local/bin
sudo cp bitcoin-22.0/bin/bitcoin* /usr/local/bin/.

To clean up the directory we’ve been working in, run:

rm -rf bitcoin-22.0*

You should now be able to start up your full node by running bitcoind -daemon in any Terminal window. If you need to stop bitcoind for any reason, the command is bitcoin-cli stop

Optional: Start Your Node At Login

Starting your node automatically each time you login to your computer makes it easy for you to contribute to the network. The easiest way to do this is to tell Bitcoin Core Daemon to start at login. In OS X, the way to start background programs at login is using a Launch Agent. Here is how to install a Launch Agent for Bitcoin Core daemon on your machine:

mkdir ~/Library/LaunchAgents
curl https://raw.githubusercontent.com/bitcoin/bitcoin/master/contrib/init/org.bitcoin.bitcoind.plist > ~/Library/LaunchAgents/org.bitcoin.bitcoind.plist

The next time you login to your desktop, Bitcoin Core daemon will be automatically started.

To support the Bitcoin network, you also need to allow incoming
connections. Please read the Network
Configuration section for details.

Upgrading Bitcoin Core

If you are running an older version, shut it down. Wait until it has completely
shut down (which might take a few minutes for older versions), then run the
installer (on Windows) or just copy over /Applications/Bitcoin-Qt (on Mac) or
bitcoind/bitcoin-qt (on Linux).

The blockchain and wallet files in the data directory are compatible between
versions so there is no requirement to make any changes to the data directory
when upgrading. Occasionally the format of those files changes, but the new
Bitcoin Core version will include code that automatically upgrades the files to
the new format so no manual intervention is required.

Sometimes upgrade of the blockchain data files from very old versions to the new
versions is not supported. In those cases it may be necessary to redownload the
blockchain. Check the release notes of the new version if you are planning to
upgrade from a very old version.

Sometimes downgrade is not possible because of changes to the data files. Again,
check the release notes for the new version if you are planning to downgrade.

Network Configuration

If you want to support the Bitcoin network, you must allow inbound
connections.

When Bitcoin Core starts, it establishes 10 outbound connections to other
full nodes so it can download the latest blocks and transactions. If you
just want to use your full node as a wallet, you don’t need more than
these 10 connections—but if you want to support lightweight clients and
other full nodes on the network, you must allow inbound connections.

Servers connected directly to the Internet usually don’t require any
special configuration. You can use the testing instructions below to
confirm your server-based node accepts inbound connections.

Home connections are usually filtered by a router or modem. Bitcoin
Core will request your router automatically configure itself to allow
inbound connections to Bitcoin’s port, port 8333. Unfortunately many
routers don’t allow automatic configuration, so you must manually
configure your router. You may also need to configure your firewall to
allow inbound connections to port 8333. Please see the following
subsections for details.

Testing Connections

The BitNodes project provides an online tool to let you test whether
your node accepts inbound connections. Before using BitNodes, you must first
ensure that your node is fully synced with the block chain. Once you’ve done so,
start Bitcoin Core (either the GUI or the daemon), wait 10 minutes, and then
visit the Bitnodes page. The tool
will attempt to guess your IP address—if the address is wrong (or
blank), you will need to enter your address manually.

Bitnodes Tool

After you press Check Node, the tool will inform you whether your port
is open (green box) or not open (red box). If you get the green box, you
don’t need to do anything—you accept inbound connections. If you get
the red box, please read the enabling
connections subsection.

For confirmation that you accept inbound connections, you can use
Bitcoin Core. Bitcoin Core can’t tell you directly whether you allow
inbound connections, but it can tell you whether or not you currently
have any inbound connections. If your node has been online for at least
30 minutes, it should normally have inbound connections. If want to
check your peer info using Bitcoin Core, choose the appropriate
instructions below:

Peer info in Bitcoin Core GUI
Peer info in Bitcoin Core daemon

GUI Peer Info

In the bottom right corner of the Bitcoin Core GUI are several icons.
If you hover over the signal strength icon, it will tell you how many
connections you have. The icon won’t turn green until you have more
than 10 active connections, which only happens if inbound connections
are allowed.

Active connections

For confirmation, you can go to the Help menu, choose Debug Window, and
open the Information tab. In the Network section, it will tell you
exactly how many inbound connections you have. If the number is greater
than zero, then inbound connections are allowed.

Debug window with inbound connections

If you don’t have inbound connections, please read the instructions for enabling inbound
connections.

Daemon Peer Info

The getconnectioncount
command will tell you how many connections you have. If you have more
than 10 connections, inbound connections are allowed. For example:

$ bitcoin-cli getconnectioncount
52

For confirmation, you can use the
getpeerinfo command to get
information about all of your peers. Each peer’s details will include
an inbound field set to true if the connection is inbound. If you
have any inbound connections, then inbound connections are allowed.

If you don’t have inbound connections, please read instructions for enabling inbound
connections.

Enabling Connections

If Bitcoin Core can’t automatically configure your router to open port
8333, you will need to manually configure your router. We’ve tried to
make the following instructions generic enough to cover most router
models; if you need specific help with your router, please ask for help
on a tech support site such as SuperUser.

Enabling inbound connections requires two steps, plus an extra third
step for firewall users:

Giving your computer a static (unchanging) internal IP address by
configuring the Dynamic Host Configuration Protocol (DHCP) on your
router.
Forwarding inbound connections from the Internet through your
router to your computer where Bitcoin Core can process them.
Configuring your firewall to allow inbound connections. This step
mainly applies to Windows users, as Mac OS X and most Linuxes do not
enable a firewall by default.

Configuring DHCP

In order for your router to direct incoming port 8333 connections to
your computer, it needs to know your computer’s internal IP address.
However, routers usually give computers dynamic IP addresses that change
frequently, so we need to ensure your router always gives your computer
the same internal IP address.

Start by logging into your router’s administration interface. Most
routers can be configured using one of the following URLs, so keep
clicking links until you find one that works. If none work, consult
your router’s manual.

http://192.168.0.1 (some Linksys/Cisco models)
http://192.168.1.1 (some D-Link/Netgear models)
http://192.168.2.1 (some Belkin/SMC models)
http://192.168.123.254 (some US Robotics models)
http://10.0.1.1 (some Apple models)

Upon connecting, you will probably be prompted for a username and
password. If you configured a password, enter it now. If not,
the Router Passwords site provides a
database of known default username and password pairs.

After logging in, you want to search your router’s menus for options
related to DHCP, the Dynamic Host Configuration Protocol. These options
may also be called Address Reservation. For example, the router page
shown below calls the option we need “DHCP Reservation”:

DHCP reservation button

In the reservation configuration, some routers will display a list of
computers and devices currently connected to your network, and then let
you select a device to make its current IP address permanent:

Easy DHCP reservation

If that’s the case, find the computer running Bitcoin Core in the list,
select it, and add it to the list of reserved addresses. Make a note of
its current IP address—we’ll use the address in the next section.

Other routers require a more manual configuration. For these routers,
you will need to look up the fixed address (MAC address) for your
computer’s network card and add it to the list. This operation differs
by operating system:

Windows 7 & 8: Press Win-R (Windows key plus the R key) to open
the Run dialog. Type cmd to open the console. Type ipconfig /all and
find the result that best matches your connection—usually a wireless
connection. Look for a line that starts with “Physical Address” and
contains a value like this:
```
  Physical Address. . . . . . . . . : 01-23-45-67-89-AB
```
Replace all the dashes with colons, so the address looks like this:
01:23:45:67:89:AB. Use that address in the instructions below.
Linux: open a terminal and type ifconfig. Find the result that
best matches your connection—a result starting with wlan indicates
a wireless connection. Find the field that starts with HWaddr and copy
the immediately following field that looks like 01:23:45:67:89:ab. Use
that value in the instructions below.
Mac OS X: open a terminal and type ifconfig. Find the result
that best matches your connection—a result starting with en1
usually indicates a wireless connection. Find the field that starts
with ether: and copy the immediately following field that looks like
01:23:45:67:89:ab. Use that value in the instructions below.

Once you have the MAC address, you can fill it into your router’s
manual DHCP assignment table, as illustrated below. Also choose an IP
address and make a note of it for the instructions in the next
subsection. After entering this information, click the Add or Save
button.

Manual DHCP reservation

Then reboot your computer to ensure it gets assigned the address you
selected and proceed to the Port Forwarding instructions below.

Port Forwarding

For this step, you need to know the local IP address of the computer
running Bitcoin Core. You should have this information from configuring
the DHCP assignment table in the subsection above.

Login to your router using the same steps described near the top of the
DHCP subsection. Look for an option called Port Forwarding, Port
Assignment, or anything with “Port” in its name. On some routers,
this option is buried in an Applications & Gaming menu.

The port forwarding settings should allow you to map an external port on
your router to the “internal port” of a device on your network as shown
in the screenshot below.

Port forwarding

Both the external port and the internal port should be 8333 for Bitcoin.
(You may also want to map port 18333 for Bitcoin’s testnet, although
this guide does not cover using testnet.) Make sure the IP address you
enter is the same one you configured in the previous subsection.

After filling in the details for the mapping, save the entry. You should
not need to restart anything. Start Bitcoin Core (if you haven’t
already) and follow the Testing Connections instructions to test
your connection.

If you still can’t connect and you use a firewall, you probably need to
change your firewall settings. See the Firewall section below.

If something else went wrong, it’s probably a problem with your router
configuration. Re-read the instructions above to see if you missed
anything, search the web for help with “port forwarding”, and ask for
help on sites like SuperUser.

We can’t provide direct support, but if you see a way to improve these
instructions, please open an issue.

Firewall Configuration

Firewalls block inbound connections. To use Bitcoin, you need to
configure your computer’s firewall to allow connections to port 8333.
This is usually as easy as starting your firewall configuration software
and defining a new rule to allow inbound connections to port 8333. For
additional information for Windows, see the links below:

Instructions for Windows Firewall
Instructions for Norton Firewall
Instructions for Mcafee Personal Firewall

Mac OS X comes with its firewall disabled by default, but if you have
enabled it, see the section Allowing Specific Applications from the
official Apple guide.

Ubuntu also comes with its firewall disabled by default, but if you have
enabled it, see the Ubuntu wiki
page for information about
adding port forwarding rules.

Once you have allowed inbound connections to port 8333, start Bitcoin
Core (if you haven’t already) and follow the Testing Connections
instructions to test your connection.

If something else went wrong re-read the DHCP, port forwarding, and
firewall instructions above to see if you missed anything, search the
web for help with “port forwarding” and “opening firewall ports”, and
ask for help on sites like SuperUser.

We can’t provide direct support, but if you see a way to improve these
instructions, please open an issue.

Configuration Tuning

This section contains advice about how to change your Bitcoin Core
configuration to adapt it to your needs.

There are two ways to change your configuration. The first is to start
Bitcoin Core with the options you want. For example, if you want to
limit it to using one CPU core for signature verification, you can start
Bitcoin Core like this:

### Bitcoin Core daemon
bitcoind -par
=
1 -daemon

### Bitcoin Core GUI
bitcoin-qt -par
=
1

Once you’ve decided you like an option, you can add it to the Bitcoin
Core configuration file. You can find that file in the following
directories:

Windows: %APPDATA%\Bitcoin\
OSX: $HOME/Library/Application Support/Bitcoin/
Linux: $HOME/.bitcoin/

To add an option to the configuration file, just remove its leading
dash. You may also need to remove any quotation marks you used in your shell.
For example, the -par option seen above would look like this in the
configuration file:

par=1

A user-friendly configuration file generator is available here.
If you have any questions about configuring Bitcoin Core, please stop by
one of our forums or live
chatrooms.

Reduce Storage

It is possible to configure your node to run in pruned mode in order to
reduce storage requirements. This can reduce the disk usage from over 350GB to
around 7GB.

Running a node in pruned mode is incompatible with -txindex and -rescan. It
also disables the RPC importwallet. Two RPCs that are available and
potentially helpful, however, are importprunedfunds and removeprunedfunds.

To enable block pruning set prune=N on the command line or in bitcoin.conf,
where N is the number of MiB to allot for raw block and undo data.

A value of 0 disables pruning. The minimal value above 0 is 550. Your
wallet is as secure with high values as it is with low ones. Higher values
merely ensure that your node will not shut down upon blockchain reorganizations
of more than 2 days – which are unlikely to happen in practice. In future
releases, a higher value may also help the network as a whole because stored
blocks could be served to other nodes.

Reduce Traffic

Some node operators need to deal with bandwidth caps imposed by their ISPs.

By default, Bitcoin Core allows up to 125 connections to different peers, 10 of
which are outbound. You can therefore have at most 115 inbound connections.

The default settings can result in relatively significant traffic consumption.

Ways to reduce traffic:

Maximum Upload Targets

-maxuploadtarget=<MiB per day>

A major component of the traffic is caused by serving historic blocks to other nodes
during the initial blocks download phase (syncing up a new node).
This option can be specified in MiB per day and is turned off by default.
This is not a hard limit; only a threshold to minimize the outbound
traffic. When the limit is about to be reached, the uploaded data is cut by no
longer serving historic blocks (blocks older than one week).
Keep in mind that new nodes require other nodes that are willing to serve
historic blocks. The recommended minimum is 144 blocks per day (max. 144MiB
per day)

Disable listening

-listen=0

Disabling listening will result in fewer nodes connected (remember the maximum of 10
outbound peers). Fewer nodes will result in less traffic usage as you are relaying
blocks and transactions to fewer nodes.

Reduce maximum connections

-maxconnections=<num>

Reducing the maximum connected nodes to a minimum could be desirable if traffic
limits are tiny. Keep in mind that Bitcoin’s trustless model works best if you are
connected to a handful of nodes.

Blocks-only mode

-blocksonly

Causes your node to stop requesting and relaying transactions unless they are
part of a block and also disables listening as described above.

This reduces your node’s bandwidth to the absolute minimum necessary to stay
synchronized with the network, about 150 megabytes incoming data per day and
about 1 megabyte of outgoing data per day, but it does mean that your node
won’t see incoming transactions until they’ve received at least one confirmation.

You will still be able to send transactions from the built-in wallet or from
peers you’ve whitelisted using the -whitelist parameter.

Running A Full Node – Bitcoin

What Is A Full Node?

Setup a Full Node

Costs And Warnings

Special Cases

Secure Your Wallet

Minimum Requirements

Possible Problems

Initial Block Download(IBD)

Linux Instructions

Bitcoin Core GUI

Bitcoin Core Daemon

Mac OS X Instructions

Mac OS X Yosemite 10.10.x+

Bitcoin Core GUI

Bitcoin Core Daemon

Upgrading Bitcoin Core

Network Configuration

Testing Connections

GUI Peer Info

Daemon Peer Info

Enabling Connections

Configuring DHCP

Port Forwarding

Firewall Configuration

Configuration Tuning

Reduce Storage

Reduce Traffic

Maximum Upload Targets

Disable listening

Reduce maximum connections

Blocks-only mode