diff --git a/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/jaxrs/ResponseBuilderImpl.java b/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/jaxrs/ResponseBuilderImpl.java
index f1a546ff5c846..7b04ab947a610 100644
--- a/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/jaxrs/ResponseBuilderImpl.java
+++ b/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/jaxrs/ResponseBuilderImpl.java
@@ -28,7 +28,7 @@ public Response.ResponseBuilder location(URI location) {
                 try {
                     String host = req.getRequestHost();
                     int port = -1;
-                    int index = host.indexOf(":");
+                    int index = host.lastIndexOf(":");
                     if (index > -1) {
                         port = Integer.parseInt(host.substring(index + 1));
                         host = host.substring(0, index);
@@ -69,7 +69,7 @@ public Response.ResponseBuilder contentLocation(URI location) {
                 try {
                     String host = req.getRequestHost();
                     int port = -1;
-                    int index = host.indexOf(":");
+                    int index = host.lastIndexOf(":");
                     if (index > -1) {
                         port = Integer.parseInt(host.substring(index + 1));
                         host = host.substring(0, index);
diff --git a/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/jaxrs/RestResponseBuilderImpl.java b/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/jaxrs/RestResponseBuilderImpl.java
index a62003cbef6a5..43c98757afe21 100644
--- a/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/jaxrs/RestResponseBuilderImpl.java
+++ b/independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/jaxrs/RestResponseBuilderImpl.java
@@ -28,7 +28,7 @@ public RestResponse.ResponseBuilder<T> location(URI location) {
                 try {
                     String host = req.getRequestHost();
                     int port = -1;
-                    int index = host.indexOf(":");
+                    int index = host.lastIndexOf(":");
                     if (index > -1) {
                         port = Integer.parseInt(host.substring(index + 1));
                         host = host.substring(0, index);
@@ -69,7 +69,7 @@ public RestResponse.ResponseBuilder<T> contentLocation(URI location) {
                 try {
                     String host = req.getRequestHost();
                     int port = -1;
-                    int index = host.indexOf(":");
+                    int index = host.lastIndexOf(":");
                     if (index > -1) {
                         port = Integer.parseInt(host.substring(index + 1));
                         host = host.substring(0, index);