Lockdown pages

Is there way to provide an access to lockdown pages for users having dynamic ip?

If you mean to block someone who’s IP address keeps changing, then no.

If you want to block everybody else, but only allow specific users, you’ll need some sort of login. Cloudflare’s Access is free for the first five users:

I configured lockdown pages accordingly to this page: https://support.cloudflare.com/hc/en-us/articles/115001595131-Locking-down-URLs-in-Cloudflare

But now I have brute force attack on locked down URL from IP that not in permitted scope.
Any suggestions ?