I am suffering from a brute force attack and we have more than 2000 members who can’t login to the site.
https://www2.suresupport.com/brute-force-attack-detected.html
We installed the plugin “wordfence” but I found out that a lot of IPs tried to login with the username “admin”
I was thinking, maybe we can have an option in the “login” area to activate “simple press login captcha” to block these brute force attack.
What do you recommend us to do?
I like the limit login attempts. http://wordpress.org/plugins/limit-login-attempts/ It stops the bots from guessing after so many tries.
Adding a captcha is good too. Sometimes more than just one thing helps. 
Trying the username of Admin is also not uncommon. You shouldn’t use that username at all on the site.
How other members manage this?
because after 20 bruteforce attack, our server says,
https://www2.suresupport.com/brute-force-attack-detected.html
and captcha can’t stop the message. Failed login attempts -> it doesn’t really work because brute force is attacking from 20 different IPs
I do the limit login attempt things… wont stop but does slow down… would suggest searching wp forums as they have suggestions such as http authentication and other more obtrusive steps…