Is there any way to block the non domain calls using cloud armor on external load balancer?

[anilmoregfs]

Is there any way to block the non-domain calls using cloud armor on an external load balancer?
I have tried request.headers['host'].lower() != "mycompany.com' but still there are calls coming 

I am looking for something like

request.URL.lower() != 'mycompany.com'