I built a discourse today but get many new user registration spam. [image] [image] Many are from the same IP and they don’t pass the email verification. Due to the limited email I can send a day (a free plan), how to prevent this kind of spam? For example, add a CAPTCHA when signing up? Thanks

Even though they can’t post, they do some random things such search queries, [Screenshot 2025-03-17 at 4.34.59 PM] or seemingly trying to hack the auth system: Job exception: Net::SMTPAuthenticationError (google_oauth2) Authentication failure! invalid_credentials: OAuth2::Error, invalid_grant: Bad Request { "error": "invalid_grant", "error_description": "Bad Request" } (google_oauth2) Authentication failure! csrf_detected: OmniAuth::Strategies::OAuth2::CallbackError, csrf_detected | CSRF detected

I suggest adding qq.com to the setting email domains blacklist.

But the man change to @126.com and continue spam..

Yes, they may or may not. Until it happens it’s just a theoretical problem. Most of the time this is all automated spam, so it’s unlikely to happen unless another bot targets you. You may also disable email signup and restrict to social logins (Twitter, Facebook, Google, Github, etc) which doesn’t send emails for new accounts.

Can we add CAPTCHA before sending email verification?

No better idea? I think it’s a basic issue of anti spam but no solution in discourse amazingly.

Can you provide more detail? Did you blacklist both of the problem email domains as requested?

@codinghorror Yes, after blocking this mail address, the spamer will change to another address like @126.com, @gmail.com, @icloud.com and continue signup new users with bot.

Seems these signups are coming from the same IP address ? Something would probably need to be done there. Block an IP address after x signups during a certain time frame ? Or forbid another signup from an identical IP address for some time ?

@Mevo But when I block and delete these IP, the spamer begin to use proxy to change his IP constantly and sign up new users.

How to prevent registration spam

Product Support

livc (Armin Li) October 7, 2019, 4:45pm 6

By the way, how to disable email signup and only allow new user from social login?

Anyway to only allow new user from social login?

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How to prevent registration spam

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