http://www.admin10000.com/document/72.html
解决 NAT issue
https://wiki.filezilla-project.org/Network_Configuration#Passive_mode
解决(?) TLS warning-not sure if it‘s really solved
http://www.bkjia.com/Linuxjc/1002942.html
原文：http://www.cnblogs.com/amigo/p/5625060.html