Server IP is pointing at some unknown (attacker) domain which has http. If I deny the http rule from ufw does that attacker site will be open?

Question

My server IP is pointing to the two domains. One is pointed to my client's domain and other one is the annonymus/attacker. The attacker site has http. So if I apply ufw deny rule then will it stop using my site's data?

Like this:

sudo ufw deny from MyServerIP to any

I am just confused whether I should execute that deny command or not.