Do I have to use Exchange on my server (windows 2003) or I can use standard smtp/pop3 services ? I really dont like Exchange and I need to secure my smtp from spammers. I tried everything but I cant secure my smtp with standard smtp service. I cant check Anonymous access to my smtp because I get toooons of emails from spammers . I cant put relay on specific ip , because I dont know form what pc my clients will send email and its not solution for me. So how can I secure my smtp ?