We used a shared host for one of our projects and recently noticed a lot of emails not making it to their intended destinations. It turns out that someone else on our shared host was using it to send spam and, as a result, everyone’s email from that IP address was marked as spam as well.
How can you find out if your mail server has been blacklisted for spamming? Use these tools below:
Spamhaus SBL Blacklist
MX Toolbox Spam Blacklist lookups
Also, if you have your own dedicated server (or rather dedicated IP address, which is a good thing), make sure you get a reverse DNS entry for your IP address from your provider – this helps a lot in avoiding overly aggressive spam filtering since it creates a bit more trust in your IP address and mail server.
Not sure if you have a reverse DNS entry? Use a lookup tool such as this:
Happy emailing! Just make sure you follow local and international laws on spamming.
