Merge branch '3.1.x'

Closes gh-36124

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/reactive/function/client/HttpComponentsClientHttpConnectorFactory.java

@@ -39,7 +39,7 @@ class HttpComponentsClientHttpConnectorFactory
 
 	@Override
 	public HttpComponentsClientHttpConnector createClientHttpConnector(SslBundle sslBundle) {
-		HttpAsyncClientBuilder builder = HttpAsyncClients.custom();
+		HttpAsyncClientBuilder builder = HttpAsyncClients.custom().useSystemProperties();
 		if (sslBundle != null) {
 			SslOptions options = sslBundle.getOptions();
 			SSLContext sslContext = sslBundle.createSslContext();

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/client/ClientHttpRequestFactories.java

@@ -175,7 +175,7 @@ public final class ClientHttpRequestFactories {
 				connectionManagerBuilder.setSSLSocketFactory(socketFactory);
 			}
 			PoolingHttpClientConnectionManager connectionManager = connectionManagerBuilder.build();
-			return HttpClientBuilder.create().setConnectionManager(connectionManager).build();
+			return HttpClientBuilder.create().useSystemProperties().setConnectionManager(connectionManager).build();
 		}
 
 	}