尝试从FTP下载文件会导致"500 Illegal PORT command"错误

Question

如果我在本地执行此操作,一切正常:

require 'net/ftp'

ftp=Net::FTP.new("myftpserver.com", "username", "password")

ftp.getbinaryfile("/myfile.zip","localfile.zip")
ftp.close

如果我尝试在我使用的Linux服务器上执行它,结果是:

/usr/local/lib/ruby/1.9.1/net/ftp.rb:273:in `getresp': 500 Illegal
PORT command. (Net::FTPPermError)   from
/usr/local/lib/ruby/1.9.1/net/ftp.rb:281:in `voidresp'  from
/usr/local/lib/ruby/1.9.1/net/ftp.rb:304:in `block in voidcmd'  from
/usr/local/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'   from
/usr/local/lib/ruby/1.9.1/net/ftp.rb:302:in `voidcmd'   from
/usr/local/lib/ruby/1.9.1/net/ftp.rb:317:in `sendport'  from
/usr/local/lib/ruby/1.9.1/net/ftp.rb:325:in `makeport'  from
/usr/local/lib/ruby/1.9.1/net/ftp.rb:358:in `transfercmd'   from
/usr/local/lib/ruby/1.9.1/net/ftp.rb:420:in `block (2 levels) in
retrbinary'   from /usr/local/lib/ruby/1.9.1/net/ftp.rb:166:in
`with_binary'   from /usr/local/lib/ruby/1.9.1/net/ftp.rb:419:in `block
in retrbinary'  from /usr/local/lib/ruby/1.9.1/monitor.rb:201:in
`mon_synchronize'   from /usr/local/lib/ruby/1.9.1/net/ftp.rb:418:in
`retrbinary'  from /usr/local/lib/ruby/1.9.1/net/ftp.rb:539:in
`getbinaryfile'

可能是什么问题呢？

Answer 1

我在http://www.ruby-forum.com/topic/161274找到了答案:

除了防火墙之外,活动的ftp在NAT设备后面不起作用.Ftp服务器有时会说非法端口命令,如果你告诉他们你的地址是私有IP地址,如192.168.x(你在nat设备后面的网络上的地址)

添加:

ftp.passive = true

固定它.