Spam attacks once again cause Bitcoin network node count to drop

Last week, an unknown person or organization sent a large number of junk transactions to the Bitcoin network, which took up up to 88,000M or 1GB of memory on node clients (clients that store and transmit transactions).

Jay杰伊•费尔迪斯from node hardware manufacturer Bitseed told CoinDesk that many lower-spec node clients simply can’t keep up:

“Eventually, the accumulated transactions fill up the node’s memory, causing the node computer to slow down or even freeze. If a node is too slow, the Bitcoin network considers it invalid and offline. I estimate that most offline nodes simply stop functioning because they can’t keep up.”

On Thursday, Bitnodes showed a 10% drop in node count.

Yesterday, although the memory pool returned to normal (about 4MB) and core developer杰夫•加兹克also implemented a quick fix for node operators, the total number of nodes reached 5030, but it was still a 16% decrease compared to before the "attack".

Stress Testing

Over the past year, the Bitcoin network has been subjected to a number of so-called “stress tests” that flooded the network with many small transactions. While some argue that these actions are justified, others blame the institutions that initiated the “stress tests,” such as Coinwallet.

While node operators cannot prevent stress testing, there are methods that can help mitigate its negative effects.

Garzik implemented a “quick fix” on Monday, dubbed “Minrelaytxfee,” which tweaks each node to reject transactions below a certain fee.

The latest version of the Bitcoin Core client, which was recently released, has a default transaction fee of 0.00001 bitcoins per KB. It has now been increased to 0.00005 bitcoins per KB (5000 satoshis).

Garzik himself admitted that this is an "unpleasant solution" and he is working on a better solution with other core developers Matt Corallo, Pieter Wuille and彼得•托德.

Todd said:

“Almost everyone on the Bitcoin Core team is working on a solution to this problem, primarily by making proposals, reviewing them, and writing code.”

Todd also told CoinDesk:

“The difficulty lies in how to make the attacker pay for his behavior. In order to come up with a perfect solution without loopholes, the core developers have made many attempts.”

However, like any change that could affect the Bitcoin ecosystem, not everyone agrees with the changes they make, such as Mike Hearn's decision to launch the Bitcoin XT client.

Some believe that different fees across nodes will make it difficult to conduct transactions, which is a potential problem for service providers that want to conduct transactions at a low cost, such as smaller wallets.

Node Operator Altruism

Unlike miners, node operators cannot receive Bitcoin rewards. Many people who run nodes voluntarily run nodes just because they are interested in maintaining the Bitcoin network, thereby maintaining the decentralization of the Bitcoin network and making the Bitcoin network healthier.

托马斯•怀特, a hobbyist who has been running different nodes for the past 15 months, told CoinDesk that he did so because he had paid fees to a server.

“As an avid Bitcoin user, I am well aware of the importance of keeping the Bitcoin network decentralized…Operating the Bitcoin blockchain does not negatively impact other people or institutions, but rather benefits the Bitcoin community.”

He said that while last week's junk trade didn't affect him, it had a very negative impact on others with limited hard drive space.

A Reddit user named “aaaaaaaarrrrrgh” who is also a node operator, was very upset about last week’s spam transactions and expressed his dissatisfaction online:

“I’ve restarted my (XT) node and tried to monitor it through Bitnodes, but if it doesn’t work, forget it. You ask me why I run the node, I can’t give you an answer, I just know that I have good intentions and want to maintain the Bitcoin network. But if things become annoying, then I won’t run it.”

Bitnodes (now owned by 21st Century Fox) hopes to encourage node operators to continue running by giving them a certain amount of Bitcoin rewards, and also hopes that more people will join, but some node operators still give up.

Reddit user "introshine" said he has spent $400 on hosting fees in the last year alone:

“I had to run 28 nodes offline, and my computer memory pool was overwhelmed. In the last few months, I ran out of money. I’m sorry to say that I gave up.”

Original article: http://www.coindesk.com/bitcoin-node-numbers-fall-after-spam-transaction-attack/
By Grace Caffyn
Translator: printemps
Editor: printemps
Source (translation): Babbitt Information