8 ms·

How would one get around this if they found themselves in such a situation?

• est 1y ago
  In this exact scenario, just use ports other than :443 But GFW certainly had the capability to block all ports. So no one really knew.
  • SuperMouse 1y ago
    [dead]
• molticrystal 1y ago
  Well for starters recreate the situation and test out different approaches. Thanks to the detailed analysis that can be attempted. If I understand right, a good next step would would be with eBPF or some type of proxy ignore the forged RST+ACK at the beginning. Then it would come testing to see if sending a bunch of ACK packets, perhaps with sequence numbers that would when reconstructed could complete the handshake. Trying to send them alongside the SYN+ACK or even before if it can be predicted. Maybe try sending some packets with sequence id 0 as well to see what happens.
  • kotri 1y ago
    > ignore the forged RST+ACK See <Ignoring the Great Firewall of China> in 2006. That won't work if RST/ACK was injected to both sides. > Then it would come testing to see if sending a bunch of ACK packets, perhaps with sequence numbers that would when reconstructed could complete the handshake. Trying to send them alongside the SYN+ACK or even before if it can be predicted. Maybe try sending some packets with sequence id 0 as well to see what happens. This is an interesting approach already being utilized, namely TCB desync. But currently most people tend to buy VPN/proxy services rather than studying this.
    • billy99k 1y ago
      I've been using Astrill to bypass the GFW for almost a decade. It's a bit expensive, but worth it.