hello,... these several weeks, i have been contacted from the person or company that telling want to buy some advertising space on my site. the first email i was reject, because the site is contain "casino and gambling site" the second, he was want to buy some space on my site... my question : how do we know is there email spam or not ? thanks
Its easy to check. Do some due diligence using google. If the email address associate with many bad comment then it should be fraud. The other thing you can do is reply back the email and see whether is the email is answered in proper manner.
Check the domain name entering into a web browser to know whether it open a site of legitimate business? Also Use Spamassassin for SPAM detection.