not able to start rails application as port 3000 is already in use.

[vfolio] bundle exec thin start

Using rack adapter
Thin web server (v1.5.0 codename Knife)
Maximum connections set to 1024
Listening on 0.0.0.0:3000, CTRL+C to stop
/Users/dfang/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/gems/eventmachine-1.0.0/lib/eventmachine.rb:526:in start_tcp_server': no acceptor (port is in use or requires root privileges) (RuntimeError) from /Users/dfang/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/gems/eventmachine-1.0.0/lib/eventmachine.rb:526:instartserver'
from /Users/dfang/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/gems/thin-1.5.0/lib/thin/backends/tcpserver.rb:16:in connect' from /Users/dfang/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/gems/thin-1.5.0/lib/thin/backends/base.rb:55:inblock in start'
from /Users/dfang/.rbenv/versions/2.0.0-p0/lib/ruby/gems/2.0.0/gems/eventmachine-1.0.0/lib/eventmachine.rb:187:in `call'

usually, killall ruby is ok for me , but won't work this time .
and ps aux | grep ruby, ps aux | grep rails, ps aux | grep thin
returns nothing............

it's weired.... but i found this (http://www.codebeerstartups.com/2012/12/not-able-to-start-rails-application-as-port-3000-is-already-in-use/)

lsof -i :3000

[vfolio] lsof -i :3000
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
VBoxHeadl 6884 dfang 37u IPv4 0x788a78e3893d821 0t0 TCP *:hbci (LISTEN)

it turns out i forwarded the port 3000 in my vagrant box, so i change this port and reload the box,
thin start works ok now .........