Classic asp emails are going to spam instead of inbox

Question

I have moved my classic asp websites from vps to dedicated server(windows server 2012). All the emails are going to spam instead of inbox(gmail and hotmail), emails are not at all receiving at yahoo. I have properly configured smtp on windows server.

Answer 1

Most receiving email servers are quite picky about where your email is sent from. They check your sending IP address and can choose to classify your email as spam or reject it all together unless all of the following things are true:

1. reverse-DNS for you IP address should give a proper name (and not look like a dynamic or dial-up address)
2. the reverse-DNS should again forward resolve to the same IP address
3. your IP address must not be on any blocklist or have a bad reputation. The problem here is that there are may different blocklists and you do not necessarily know what lists they check. You could test your IP address at http://multirbl.valli.org and see if there are any known issues
4. the domain-name of your sender email address can have SPF policies published in DNS that explicitly tells the world what IP addresses are allowed to send emails for that domain, and if your IP address is not included you are considered a fake sender

And there can be any number of other anti-spam/forgery checks in place that cause trouble for you. The best bet would be for you to relay your outgoing emails via an official mail server (for the domain your are trying to send from), as that already has the above things covered, but that usually requires some authentication mechanism or other agreement with the real mail server you want to use.

All these checks by the receiving end are there to stop spam and other unwanted emails. In order to not be classified as a spammer, you cannot just set up a random server at a random address and start sending emails from a random email address (or email address that normally are sent from some more official email server).