How to access pod by IP when using Istio - kubernetes

Question

I need to use spring boot admin to manage my pods. And I found that spring boot admin failed to call pod actuator endpoints.
I think it may be caused by Istio. Istio might block direct IP address visit. The following are my tests:
If I call a page by POD IP address, I got the following error:
# curl -I http://10.40.133.41
HTTP/1.1 503 Service Unavailable
content-length: 95
content-type: text/plain
date: Thu, 03 Nov 2022 03:10:54 GMT
server: envoy
If I call the same page by service name, it's fine:
# curl -I http://httpbin
HTTP/1.1 200 OK
server: envoy
date: Thu, 03 Nov 2022 03:09:02 GMT
content-type: text/html; charset=utf-8
content-length: 9593
access-control-allow-origin: *
access-control-allow-credentials: true
x-envoy-upstream-service-time: 3
Does anyone know how to enable a pod to access another pod by IP address directly when using Istio? Or is there any other solution to using spring boot admin when using Istio?
I tried to add service name as the Host request header when calling a web page. But it seems that Istio would find a pod by service name instead of using the IP address.
The following is an example that I used a wrong IP, and the system returns success status:
# curl -I -H "Host: httpbin" http://100.40.133.41
HTTP/1.1 200 OK
server: envoy
date: Thu, 03 Nov 2022 03:39:00 GMT
content-type: text/html; charset=utf-8
content-length: 9593
access-control-allow-origin: *
access-control-allow-credentials: true
x-envoy-upstream-service-time: 2