Why nginx ingress controller can print the correct client ip, nginx started in the pod cannot get the correct client ip

Rancher 2.x
1

My nginx is behind load balancing, did load balancing modify the X-Real-Ip request header?
I print nginx.conf in nginx ingress controller that has forwarded the X-Real-IP.

2

The nginx parameter real ip from deployed within the pod must be set right. Otherwise remote addr is not the user’s ip