Sendmail, PHP, etc

[Justin French]

Greetings,

I can't get sendmail to work... I've done a fair bit of googling, 
including this bunch of comands, which i've seen in a few places:

chmod g-w /
chmod g-w /etc/
chmod g-w /etc/mail

Then I try sending a message to root:

# sendmail root
test
.

and to my own email address:

# sendmail justin at indent.com.au
test2
.

... but no luck.

I've also tried sending email from within a PHP script (PHP 4.2.3, 
Apache 1.3.x), but no luck, and no errors.


Do I need a specific port open in the firewall?
What other steps do I need to take to enable sendmail, and check that 
it's working?


Apologies if this is the wrong list...

TIA
Justin