X-Forwarded-For not forwarded correctly by Spring Cloud Gateway 4.3.0 after upgrading to Spring Cloud 2025.

Hi spring cloud gateway team,

After upgrading to Spring Cloud 2025, I found that Spring Cloud Gateway 4.3.0 does not correctly forward the X-Forwarded-For header.

Expected behavior:
Spring Cloud Gateway should forward the real client IP in X-Forwarded-For to microservices.

Actual behavior:
Using tcpdump, I observed that Gateway WebFlux 4.3.0 (included in Spring Cloud 2025) does not forward X-Forwarded-For at all.

Configuration tried:
I set the following property as suggested in the docs:

spring.cloud.gateway.server.webflux.trusted-proxies=10\.\\d{1,3}\.\d{1,3}\.\d{1,3}|192\.168\.\d{1,3}\.\d{1,3}|169\.254\.\d{1,3}\.\d{1,3}|127\.\d{1,3}\.\d{1,3}\.\d{1,3}|100\.6[4-9]{1}\.\d{1,3}\.\d{1,3}|100\.[7-9]{1}\d{1}\.\d{1,3}\.\d{1,3}|100\.1[0-1]{1}\d{1}\.\d{1,3}\.\d{1,3}|100\.12[0-7]{1}\.\d{1,3}\.\d{1,3}|172\.1[6-9]{1}\.\d{1,3}\.\d{1,3}|172\.2[0-9]{1}\.\d{1,3}\.\d{1,3}|172\.3[0-1]{1}\.\d{1,3}\.\d{1,3}|0:0:0:0:0:0:0:1|::1|fe[89ab]\p{XDigit}:.*|f[cd]\p{XDigit}{2}:.*+

But it has no effect.

As I understand, this config is for trusting other proxies. In my case, users access Spring Cloud Gateway directly (no proxy).

Question:
How can I configure Spring Cloud Gateway so that it always forwards the real client IP as X-Forwarded-For to downstream services?
Thanks!!!

Start by reproducing the issue with Spring Cloud Gateway 4.3.0, the shown trusted-proxies setting, and tcpdump while checking the downstream service. Investigate how WebFlux handles X-Forwarded-For when users connect directly rather than through a trusted proxy. Done means the real client IP is forwarded consistently or the supported configuration and limitation are documented.