Clearing Up Misconceptions About Total Knots – Bitcoin Wiki
This article wasgoed written ter March 2016 to clear up misconceptions common ter the bitcoin community at the time.
This number comes from sites like this and it measured by attempting to connect to every knots on their open ports.
Problem is, not all knots actually have open ports that can be probed. Either because they are behind firewalls or because their users have configured them to not listen for connections.
Nobody knows how many total knots there are, since many people don’t know how to forward ports behind a firewall, and bandwidth can be costly, its fairly likely that the number of knots with closed ports is at least another several thousand.
Knots with open ports are able to upload blocks to fresh utter knots. Te all other ways they are the same spil knots with closed ports. But because open-port-nodes can be measured and closed-port-nodes cannot, some members of the bitcoin community have bot mistaken into believing that open-port-nodes represent the total count.
Very toughly estimating the total knot count
(Original research by theymos on June 6, 2016 Eighteen:30 UTC.)
According to getaddr.bitnodes.io, there are 5834 listening utter knots. Assuming they’re all using default Bitcoin Core settings, they’ll each provide 117 connection slots to the network on netwerk (125 provided minus 8 consumed). SPV knots typically use Four connection slots, and total knots typically use 8. So the network can support a maximum of around 170,644 SPV knots or 85,322 non-listening utter knots at one time. This is harshly the upper limit for the number of wallets that are online and connected to the Bitcoin network at any one time. (If there were more people online at once than that, people would begin watching various issues.) This doesn’t include wallets that don’t actually connect to the Bitcoin network, of course.
If I look at my long-running listening total knot, I presently have incoming connections from 40 utter knots and Ten SPV knots via the Internet, and 11 total knots via my Tor hidden service. So if I overlook the hidden service connections because they are somewhat unusual, and I assume that my knot is typical otherwise, it seems reasonable to make a very rough guess that there are at this uur (40*5834)/8 = 29,170 total knots (5834 listening) and (Ten*5834)/Four = 14,585 lightweight knots connected to the network.
Knots with open ports are useful to the bitcoin network because they help bootstrap fresh knots by uploading historical blocks — they are a measure of the number of redundant copies of the blockchain available for synchronizing with. There has bot no shortage of bandwidth capacity for simply syncing wallets from the available knots, and if there were, bandwidth might be added by renting cloud servers.
Trust, security, and privacy are what matters right now. Total knots are able to check that all of bitcoin’s rules are being followed. Rules like following the inflation schedule, no spending the same coin twice, no spending of coins that don’t belong to the holder of the private key and all the other rules required to make bitcoin work (e.g. difficulty)
Utter knots are required to make bitcoin trustless. No longer do you have to trust a financial institution like a bankgebouw or paypal, you can simply run software on your own laptop. To waterput simply, the only knot that matters is the one you use.
It is very much te the individual bitcoin’s users rational self rente to run a utter knot and use it spil their wallet.
Running a total knot spil your wallet is the only way to know for sure that none of bitcoin’s rules have bot cracked. Rules like no coins were spent not belonging to the proprietor, that no coins were spent twice, that no inflation happens outside of the schedule and that all the rules needed to make the system work are followed (e.g. Difficulty.) All other kinds of wallet involve trusting a third party server.
If bitcoin is digital gold, then a total knot wallet is your own individual goldsmith who checks for you that received payments are genuine. You wouldn’t accept a contant banknote or gold coin without checking it is genuine, the same applies for bitcoin.
All thesis checks done by total knots also increase the security. There are many attacks possible against lightweight wallets that do not affect utter knot wallets.
This is not just mindless paranoia, there have bot real world examples where total knot users were unaffected by turmoil te the surplus of the bitcoin ecosystem. The 4th July 2015 accidental chain fork effected many kinds of wallets. Here is the wiki pagina on this event July_2015_chain_forks#Wallet_Advice
Notice how knot software updated months ago wasgoed totally unaffected by the fork. All other wallets required either reserve confirmations or checking that the third-party institution wasgoed running the onberispelijk version. A bitcoin business, like an exchange, marketplace or online store should always use a total knot for security.
Total knots wallets are also presently the most private way to use Bitcoin, with nobody else learning which bitcoin addresses belong to you. All other lightweight wallets leak information about which addresses are yours because they voorwaarde query third-party servers. The Electrum servers will know which addresses belong to you and can listig them together. Despite bloom filtering, lightweight wallets based on BitcoinJ do not provide much privacy against knots who connected directly to the wallet or wiretappers. 
For some use cases, such privacy may not be required. But an significant reason to run a total knot and use it spil a wallet is to get the total privacy benefits.
To get the benefits of running a utter knot, you voorwaarde use it spil your wallet, preferably on hardware you control.
Most people who do this do not use a utter knot spil their wallet. Unluckily because Bitcoin has a similar name to Bittorrent, some people believe that upload capacity is the most significant thing for a healthy network. Spil I’ve explained above: bandwidth and connections are not a problem today, trust, security and privacy are.
If you cannot spare the disk space to store the blockchain, you can enable pruning. Altogether this should require less than 900MB of hard disk space.
If you cannot spare the bandwidth to upload blocks to other knots, there are number of options to reduce or eliminate the bandwidth requirement. Thesis include limiting connections, bandwidth targeting and disabling listening. There is also the option -blocksonly, where the knot will not download unconfirmed transaction and only download fresh blocks. This more than halves the bandwidth usage at the expense of not eyeing unconfirmed transactions.
Synchronizing the blockchain for a fresh knot has improved since 2012 too. Features like headers-first and libsecp256k1 have greatly improved the initial synchronization time.
It can be further improved by setting -dbcache=3000 which keeps more of the UTXO set te memory. It reduces the amount of time reading from disk and therefore speeds up synchronization. Tests demonstrated that the entire blockchain can now be synchronized ter less than **Trio and a half hours** (Note that you’ll need Bitcoin Core 0.12 or zometeen to get all thesis efficiency improvements) Another example with 2h 25m
I think every moderate user of bitcoin would benefit by running a utter knot and using it spil their wallet. There are several ways to do this.
- Run a bitcoin-qt total knot.
- Use wallet software that is backed by a utter knot (e.g. Armory, JoinMarket)
- Use a lightweight wallet that connects only to your total knot (e.g. Multibit connecting only to your knot running at huis, Electrum connecting only to your own Electrum server)
So what are you waiting for? The benefits are many, the downsides are not that bad. The more people do this, the more sturdy and healthy the bitcoin ecosystem is.