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I have my own email server and I've recently noticed that many of the emails I sent ended up in the recipients' spam folder. I have verified the IP of my mail server and it's not in any blacklist. What could be causing this? Could it be that my IP doesn't have a long history? How can I fix this?

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closed as off topic by Wuffers, Simon Sheehan, Nifle, Ƭᴇcʜιᴇ007, Tom Wijsman Mar 5 '12 at 1:22

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Long history? Is the IP a static address? – Paul Mar 4 '12 at 3:25
Don't send spam, maybe? At last, it's recipient's side solution, you have to ask other side, not blindly find non-existent answer – Lazy Badger Mar 4 '12 at 8:58
Ask one of the recipients to forward you a mail that went to Spam. Then check the mail headers for possible information why it went to Spam. – Oliver Salzburg Mar 4 '12 at 13:45

I recommend the MXToolBox SuperTool:

  • To check if your IP is on any blacklist, enter the command:

  • To check if your IP has a reverse DNS record, enter the command:

  • To check if your IP has a forward-confirmed reverse DNS, enter the command:


    where hostname if the result of the second check. It should return your IP.

Other things you can try to pass common spam filters (like Google's):

  • Set up a SPF record.

  • Sign your emails with the DKIM method.

  • Request your IP to be whitelisted (e. g., on

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and after all get content-analyzer on recipient side, which consider text as spam anyway – Lazy Badger Mar 4 '12 at 8:56

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