Re: Max. no of allowed "rcpt to" commands in a smtp session?

> Spammers always use weakness of smtp protocol. For example yahoo can
> accept any mail form any client. They do not check if the sender is an
> SMTP server and it's MX record to be ensure that sender's domain and
> IP belongs to right smtp server that has a MX record.
since there's no protocol requirement that an SMTP be both a client and 
a server on the same IP address, such a check would be tremendously
stupid and misguided.