How is Stellar network protected against spam? Are there scalability solutions?

Question

After todays meeting with Stellar dev in Kraków some issues have raised in my mind that I couldn't easily find the answer to:

1. From what I've heard, Stellar is capable of handling like 1000tx/s. With a transaction cost beeing a fixed amount of 0.00001 XLM. What exactly stops some entity to issue like 10,000tx/s for merely $0.04? What is the protection mechanism for such "attack"?
2. The second question is connected with the first one, because 1000tx/s seems like a lot but considering the fact that it's supposed to be a platform for decentralized asset exchanges it's not really that much. Binance CEO said that at the current stage they are able to process even 1.4M transactions per second, and they plan to later on move their exchange on blockchain but at the moment there is no blockchain capable of handling such volumes. What is the Stellar approach to scalability? Is there a plan to maybe move the transactions offchain with Lightning Network?

Regards, Piotr

Answer 1

I have no clue for the 2nd question. For the first one...

Horizon server submits transactions to the Stellar network. This server does not let you to sustain 1000tx/s from the same IP for more than several seconds, so you cannot DOS attack from a single machine (without changing IP).

By default this is set to 3600 requests per hour—an average of one request per second https://www.stellar.org/developers/horizon/reference/rate-limiting.html

You may check this header with your browser at https://horizon-testnet.stellar.org using the Development tools (F12 for Chrome). On refreshing the page, the "X-Ratelimit-Remaining" header will minus by 1.