It is possible to set up a verification code for guests to ensure they are human, I'm using phpBB2 theme is that might mean something.

To register?

When someone decides to post as a guest. This issue is that the forum keeps receiving a bunch of nonsense spam posts from what I presume is a bot.

There should be a verification for guest who post, but the best thing would to remove guest from posting and register to the forum to post.

You're right, I just noticed it only appears after you attempt to post the topic, my mistake.

Alright thanks.

That is fine.

Thanks for putting the solved icon.
Solved => Locked