who is qualified for smtp server?

[lovekang]

Can everybody set smtp server(windows, Linux, Unix)?
I mean if someone is online, he or she can send mail?
if so, what if some notorious guys send lot's of spam mail?
if not so, which conditions have to be met?

 

[WhoKilledKenny]

Can everybody set smtp server(windows, Linux, Unix)?

If one has the knowledge to do so I would imagine, yes...

I mean if someone is online, he or she can send mail?

As long as port 25 is not blocked, then yes...

if so, what if some notorious guys send lot's of spam mail?

Do like most companies, set up spam filters or purchase a third party anit-spam.

if not so, which conditions have to be met?

Condition regarding email? As long as port 25 is not blocked you can send email all day. As far as receiving email, from a high level, you would have to register a domain name and have your MX record hosted on the Internet. The MX Record would point to the public IP address of you SMTP server.