Должно возвращаться что-то вроде этого:
/usr/lib/ruby/1.8/net/http.rb:560:in `initialize': getaddrinfo: Name or service not known (SocketError)
from /usr/lib/ruby/1.8/net/http.rb:560:in `open'
from /usr/lib/ruby/1.8/net/http.rb:560:in `connect'
from /usr/lib/ruby/1.8/timeout.rb:53:in `timeout'
from /usr/lib/ruby/1.8/timeout.rb:93:in `timeout'
from /usr/lib/ruby/1.8/net/http.rb:560:in `connect'
from /usr/lib/ruby/1.8/net/http.rb:553:in `do_start'
from /usr/lib/ruby/1.8/net/http.rb:542:in `start'
from /usr/lib/ruby/1.8/net/http.rb:374:in `get_response'
from /usr/lib/ruby/1.8/net/http.rb:356:in `get'
from httpd.rb:2