I been trying for a while to have a SMTP server running in my computer, but all the software I use do not send any email. Ialways get a
Time Out error.
I do not have firewall, what can be?
I most likely know what's going on, but I need some additional details to confirm.
If you're using Linux and Postfix, and if I'm correct, and this is usually the case when SMTP gets a time out like this, it has something to do with your MTU discovery, for more information on this, check out http://www.postfix.org/faq.html "IP path MTU discovery"
You haven't provided much information. It will be difficult for anyone to help you without more information. It could be several things including an incorrectly configured setup or the service is not running. If you're trying to run this from home, it's also highly likely that your ISP is blocking any outbound SMTP traffic. More ISP's than not do this nowadays and only allow outbound SMTP traffic that goes through their SMTP servers so they can monitor for spam and the like.