java - ホストへの経路がない - connect(2) (Errno::EHOSTUNREACH)

Question

SMTP サーバーの構成はどこにありますか?

**************/usr/lib/ruby/1.8/net/smtp.rb:551:in `initialize': No 
route to host - connect(2) (Errno::EHOSTUNREACH)
 from 
/usr/lib/ruby/1.8/net/smtp.rb:551:in `open'
 from 
/usr/lib/ruby/1.8/net/smtp.rb:551:in `do_start'
 from 
/usr/lib/ruby/1.8/timeout.rb:67:in `timeout'
 from 
/usr/lib/ruby/1.8/timeout.rb:101:in `timeout'
 from 
/usr/lib/ruby/1.8/net/smtp.rb:551:in `do_start'
 from 
/usr/lib/ruby/1.8/net/smtp.rb:525:in `start'
 from 
/usr/lib/ruby/gems/1.8/gems/mail-2.5.4/lib/mail/network/delivery_methods/smtp.rb:112:in 
`deliver!'
 from 
/usr/lib/ruby/gems/1.8/gems/mail-2.5.4/lib/mail/message.rb:248:in 
`deliver!'