How to avoid mails going to SPAM (Configuring SMTP Server on IIS)

Question

How to configure SMTP Server in IIS such that the mails sent from my Server doesn't go to the spam box of gmail, yahoo, or hotmail ?

Answer 1

To find out what all you can do to avoid emails going to SPAM folder, see this Email Server Test

Answer 2

This is a bit difficult to understand. I think there's two ways to interpret your question with two very different answers. I'll try to give both meanings I see and an answer to each question below.

1. Is there a setting I can choose on IIS's SMTP server (or any other mail server for that matter) that will stop other people marking email sent from my server as junk.

No... There are things you can do with DNS settings to manage email reputation (spf, etc) but ultimately this is a choice made by the receiving server's operator, and also by their users.

2. Help, I think my server is being exploited by spammers, because the legitimate mail I'm sending is being rejected with messages that indicate I have an open relay or am participating in sending spam. What do I do?

In general terms, you need to make sure that

• You are only accepting email to send through this server from your own internal processes... in other words that your email server is configured to only accept and forward email from servers you control.
• That these processes are secure - there was a spate of people exploiting issues in email forms on webpages, for example, to get around the problem I mention above.
• And any authentication you use to connect from the process you want to send email via this server hasn't been compromised.