In the second case, the TCP SYN request from B will arrive at NAT A directed to port 62000, but NAT A will reject the connection request because only outgoing connections are allowed.

• 第二种情况，从B传来的TCP SYN请求将能够到达端口NAT A的端口62000，但NAT A却会拒绝这个连接请求，因为只有外出的连接才允许（进入）。