syntax highlighting on files with no extension ?

There is nothing I can do about it, I've made hundreds attempts without any luck.
How on earth can I set highlight on files that have no extension, say /etc/hosts file. I would like to set highlight on comments. that's it!!!

--
--
You received this message from the "vim_use" maillist.
Do not top-post! Type your reply below the text you are replying to.
For more information, visit http://www.vim.org/maillist.php

---
You received this message because you are subscribed to the Google Groups "vim_use" group.
To unsubscribe from this group and stop receiving emails from it, send an email to vim_use+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.