telnet: Unable to connect to remote host: Cannot assign requested address

telnet报错,无论telnet什么域名或者IP的端口:
telnet: Unable to connect to remote host: Cannot assign requested address

  1. root@debian:~# telnet xxx.com 21
  2. Trying xxx.com...
  3. telnet: Unable to connect to remote host: Cannot assign requested address
  4.  
  5. 添加local_port_range
  6. echo "net.ipv4.ip_local_port_range = 1024 65000" >> /etc/sysctl.conf
  7. sysctl -p
  8.  
  9. root@debian:~# telnet xxx.com 21
  10. Trying x.x.x.x...
  11. Connected to xxx.com.
  12. Escape character is '^]'.
  13. 220 Microsoft FTP Service
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