title: rails server cannot start; getaddrinfo: nodename nor servname provided, or not known (SocketError)
body: <p>I have not found a  solution to the problem, however someone did already ask about the same problem a few days ago - (<a href="https://stackoverflow.com/questions/28689733/rails-server-keeps-exiting-socketerror">Rails Server Keeps Exiting (SocketError)</a>)</p>
  
  <p>After I start a rails server the system returns some error I cannot understand. To install Ruby on Rails on my mac I did everything as listed on <a href="http://railsapps.github.io/installrubyonrails-mac.html" rel="nofollow noreferrer">http://railsapps.github.io/installrubyonrails-mac.html</a></p>
  
  <p>here is my terminal response:</p>
  
  <pre><code>$ rails server
  =&gt; Booting WEBrick
  =&gt; Rails 4.2.0 application starting in development on http://localhost:3000
  =&gt; Run `rails server -h` for more startup options
  =&gt; Ctrl-C to shutdown server
  [2015-02-28 02:14:46] INFO  WEBrick 1.3.1
  [2015-02-28 02:14:46] INFO  ruby 2.2.0 (2014-12-25) [x86_64-darwin14]
  Exiting
  /Users/alexshel/.rvm/rubies/ruby-2.2.0/lib/ruby/2.2.0/socket.rb:232:in `getaddrinfo': getaddrinfo: nodename nor servname provided, or not known (SocketError)
      from /Users/alexshel/.rvm/rubies/ruby-2.2.0/lib/ruby/2.2.0/socket.rb:232:in `foreach'
      from /Users/alexshel/.rvm/rubies/ruby-2.2.0/lib/ruby/2.2.0/socket.rb:459:in `tcp_server_sockets'
      from /Users/alexshel/.rvm/rubies/ruby-2.2.0/lib/ruby/2.2.0/webrick/utils.rb:70:in `create_listeners'
      from /Users/alexshel/.rvm/rubies/ruby-2.2.0/lib/ruby/2.2.0/webrick/server.rb:133:in `listen'
      from /Users/alexshel/.rvm/rubies/ruby-2.2.0/lib/ruby/2.2.0/webrick/server.rb:114:in `initialize'
      from /Users/alexshel/.rvm/rubies/ruby-2.2.0/lib/ruby/2.2.0/webrick/httpserver.rb:45:in `initialize'
      from /Users/alexshel/.rvm/gems/ruby-2.2.0@global/gems/rack-1.6.0/lib/rack/handler/webrick.rb:32:in `new'
      from /Users/alexshel/.rvm/gems/ruby-2.2.0@global/gems/rack-1.6.0/lib/rack/handler/webrick.rb:32:in `run'
      from /Users/alexshel/.rvm/gems/ruby-2.2.0@global/gems/rack-1.6.0/lib/rack/server.rb:286:in `start'
      from /Users/alexshel/.rvm/gems/ruby-2.2.0@global/gems/railties-4.2.0/lib/rails/commands/server.rb:80:in `start'
      from /Users/alexshel/.rvm/gems/ruby-2.2.0@global/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:80:in `block in server'
      from /Users/alexshel/.rvm/gems/ruby-2.2.0@global/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:75:in `tap'
      from /Users/alexshel/.rvm/gems/ruby-2.2.0@global/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:75:in `server'
      from /Users/alexshel/.rvm/gems/ruby-2.2.0@global/gems/railties-4.2.0/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
      from /Users/alexshel/.rvm/gems/ruby-2.2.0@global/gems/railties-4.2.0/lib/rails/commands.rb:17:in `&lt;top (required)&gt;'
      from /Users/alexshel/workspace/myapp/bin/rails:8:in `require'
      from /Users/alexshel/workspace/myapp/bin/rails:8:in `&lt;top (required)&gt;'
      from /Users/alexshel/.rvm/gems/ruby-2.2.0@myapp/gems/spring-1.3.3/lib/spring/client/rails.rb:27:in `load'
      from /Users/alexshel/.rvm/gems/ruby-2.2.0@myapp/gems/spring-1.3.3/lib/spring/client/rails.rb:27:in `call'
      from /Users/alexshel/.rvm/gems/ruby-2.2.0@myapp/gems/spring-1.3.3/lib/spring/client/command.rb:7:in `call'
      from /Users/alexshel/.rvm/gems/ruby-2.2.0@myapp/gems/spring-1.3.3/lib/spring/client.rb:26:in `run'
      from /Users/alexshel/.rvm/gems/ruby-2.2.0@myapp/gems/spring-1.3.3/bin/spring:48:in `&lt;top (required)&gt;'
      from /Users/alexshel/.rvm/gems/ruby-2.2.0@myapp/gems/spring-1.3.3/lib/spring/binstub.rb:11:in `load'
      from /Users/alexshel/.rvm/gems/ruby-2.2.0@myapp/gems/spring-1.3.3/lib/spring/binstub.rb:11:in `&lt;top (required)&gt;'
      from /Users/alexshel/workspace/myapp/bin/spring:13:in `require'
      from /Users/alexshel/workspace/myapp/bin/spring:13:in `&lt;top (required)&gt;'
      from bin/rails:3:in `load'
      from bin/rails:3:in `&lt;main&gt;'
  </code></pre>
  
  <p>Please help.</p>