This is fairly simple, and it's actually hilarious how this works, but this was a find that I found that may help a couple of ya'll. My forum's niche is bruteforcing, and recaptcha actually stops 70% of skids out there, so it doesn't hurt to add this to your forum at all.
What you need installed before hand:
Login Captcha 1.1.0
Be sure to look at the instructions for both this and Login Captcha!
Now, if you go to System > System Settings > Members > Spam Prevention and enable recaptcha, it will show the login captcha and registration page captcha, but if you select recaptcha 2, it'll only show for the registration page. That's where this nifty tutorial comes in.
Go to your FTP, and go to the your /ips_kernel/classCaptchaPlugin/ folder.
You'll have a couple .php files: recaptcha.php and recaptcha2.php.
Rename recaptcha.php -> recaptcha.php.bk and recaptcha2.php -> recaptcha.php
Then go back to System > System Settings > Members > Spam Prevention and enable recaptcha (not recaptcha 2!).
Boom. Done. Check your login page
Now, there comes the predicament that if you're using the mobile skin, people can just change the user-agent in their bots and they bypass your captcha. Well, as much as I love to get the recaptcha to show in the mobile login as well, the only work around I found was this:
I noticed that if I just added some URL Remapping, that I can get the login to only show the full skin login page as that's the only one that has the recaptcha attached. But that's easier said than done. Because of some really weird way the array was ordered in the PHP of publicOutput, you need to change the order of as stated here and to do so you need to:
Go to your /admin/sources/classes/output/ folder
Open up publicOutput.php
Find fetchskinbyurl
Order the line as
foreach( array( '_fetchSkinByURLMap', '_fetchByMobileApp', '_fetchSkinByUserAgent', '_fetchSkinByApp', '_fetchSkinByMemberPrefs', '_fetchSkinByDefault' ) as $function )and save
Go to your main skin's URL Remapping settings
Click "Add New URL"
Make the info as such
app=core&module=global§ion=loginand save changes
Done. Check out the login on your phone and you should be redirected to your full skin login page instead of your recaptcha-less mobile skin!
This is actually something that I highly advise all IPB forums use as bruteforcing is incredibly easy on us