mail() I get crazy from this...

Hello, I repeat: my PHP mail() function does not work. Apache tells me it can not connect. I have XP, Netscape, Apache, PHP, MYSQL. I have not the faintest idea where my smpt server is. I use Netscape for reading my e-mail.I have only a raw line to the internet. I have installed a firewall. What must I do to discover what my smpt server is? I must have one. Otherwise I could not go to netscape and send mail, to hotmail etc. I apologize to be so ignorant. So, please do not tell me general things. Do not tell me that I will find the answer in any .ini file. You who reads this, please, tell me what to do exactly. In the XP environment. with friendly greetings, Peter