Regarding configuring firewall on Load Balancers

[ishu1]

I WANT TO ATTACH A FIREWALL ON MY LOAD BALANCER WHICH IS ATTACHED TO MY CLOUD RUN INSTANCE CAN I ABLE TO DO THAT?? I TRIED WITH CLOUD ARMOR IT THOUGH RESTRICTING MY APPLICATION BUT WHEN I TELNET TO THAT LB IP WITH PORT 80 IT IS SHOWING ME CONNECTED.

[SHBASI96]

Cloud Armor only protects against Layer 7 attacks, such as HTTP and HTTPS requests. It does not protect against Layer 4 attacks, such as Telnet connections.

To restrict Telnet connections to your load balancer, you can use a firewall rule that blocks TCP port 23. This will prevent anyone from Telnetting to your load balancer's IP address, regardless of whether or not they have an account on your project.

like this example : 

name: block-tcp-port-23

direction: INGRESS

target: TARGET_NAME

action: "DENY_ALL"

sourceRanges: ["0.0.0.0/0"]

protocol: "tcp"

ports: ["23"]