diff --git a/changelog.html b/changelog.html
index ef84abe2b5..fa3e9f9044 100644
--- a/changelog.html
+++ b/changelog.html
@@ -55,7 +55,9 @@ Upcoming changes</a>
 <!-- Record your changes in the trunk here. -->
 <div id="trunk" style="display:none"><!--=TRUNK-BEGIN=-->
 <ul class=image>
-  <li class=>
+  <li class=bug>
+    Port on HTTP Proxy Configure accepts characters except the digits
+    (<a href="https://issues.jenkins-ci.org/browse/JENKINS-11068">issue 11068</a>)
 </ul>
 </div><!--=TRUNK-END=-->
 
diff --git a/core/src/main/java/hudson/PluginManager.java b/core/src/main/java/hudson/PluginManager.java
index 156a38d43e..f79470ab13 100644
--- a/core/src/main/java/hudson/PluginManager.java
+++ b/core/src/main/java/hudson/PluginManager.java
@@ -37,6 +37,7 @@ import hudson.model.UpdateCenter;
 import hudson.model.UpdateSite;
 import hudson.util.CyclicGraphDetector;
 import hudson.util.CyclicGraphDetector.CycleDetectedException;
+import hudson.util.FormValidation;
 import hudson.util.PersistedList;
 import hudson.util.Service;
 import org.apache.commons.fileupload.FileItem;
@@ -565,15 +566,31 @@ public abstract class PluginManager extends AbstractModelObject {
             hudson.proxy = null;
             ProxyConfiguration.getXmlFile().delete();
         } else try {
-            hudson.proxy = new ProxyConfiguration(server,Integer.parseInt(Util.fixNull(port)),
+            int proxyPort = Integer.parseInt(Util.fixNull(port));
+            if (proxyPort < 0 || proxyPort > 65535) {
+               throw new Failure(Messages.PluginManager_PortNotInRange(0, 65535)); 
+            }
+            hudson.proxy = new ProxyConfiguration(server, proxyPort,
                     Util.fixEmptyAndTrim(userName),Util.fixEmptyAndTrim(password));
             hudson.proxy.save();
         } catch (NumberFormatException nfe) {
-            return HttpResponses.error(StaplerResponse.SC_BAD_REQUEST,
-                    new IllegalArgumentException("Invalid proxy port: " + port, nfe));
+            throw new Failure(Messages.PluginManager_PortNotANumber());
         }
         return new HttpRedirect("advanced");
     }
+    
+    public FormValidation doCheckProxyPort(@QueryParameter String value) {
+        int port;
+        try {
+            port = Integer.parseInt(value);
+        } catch (NumberFormatException e) {
+            return FormValidation.error(Messages.PluginManager_PortNotANumber());
+        }
+        if (port < 0 || port > 65535) {
+            return FormValidation.error(Messages.PluginManager_PortNotInRange(0, 65535));
+        }
+        return FormValidation.ok();
+    }
 
     /**
      * Uploads a plugin.
diff --git a/core/src/main/resources/hudson/Messages.properties b/core/src/main/resources/hudson/Messages.properties
index c4edc3a6d9..fb82bc8266 100644
--- a/core/src/main/resources/hudson/Messages.properties
+++ b/core/src/main/resources/hudson/Messages.properties
@@ -50,5 +50,7 @@ Util.pastTime={0}
 FilePath.TildaDoesntWork=''~'' is only supported in a Unix shell and nowhere else.
 
 PluginManager.DisplayName=Plugin Manager
+PluginManager.PortNotANumber=Port is not a number
+PluginManager.PortNotInRange=Port does''t range from {0} to {1}
 AboutJenkins.DisplayName=About Jenkins
 AboutJenkins.Description=See the version and license information
diff --git a/core/src/main/resources/hudson/Messages_ja.properties b/core/src/main/resources/hudson/Messages_ja.properties
index 30e521ba4e..87671bcdec 100644
--- a/core/src/main/resources/hudson/Messages_ja.properties
+++ b/core/src/main/resources/hudson/Messages_ja.properties
@@ -49,5 +49,7 @@ Util.pastTime={0} \u524d
 FilePath.TildaDoesntWork=''~'' \u306f\u3001Unix\u306e\u30b7\u30a7\u30eb\u3067\u306e\u307f\u30b5\u30dd\u30fc\u30c8\u3055\u308c\u3066\u3044\u307e\u3059\u3002
 
 PluginManager.DisplayName=\u30d7\u30e9\u30b0\u30a4\u30f3\u30de\u30cd\u30fc\u30b8\u30e3\u30fc
+PluginManager.PortNotANumber=\u30dd\u30fc\u30c8\u756a\u53f7\u304c\u6570\u5b57\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002
+PluginManager.PortNotInRange=\u30dd\u30fc\u30c8\u756a\u53f7\u304c{0}\u304b\u3089{1}\u307e\u3067\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002
 AboutJenkins.DisplayName=Jenkins\u306b\u3064\u3044\u3066
 AboutJenkins.Description=\u30d0\u30fc\u30b8\u30e7\u30f3\u3068\u30e9\u30a4\u30bb\u30f3\u30b9\u60c5\u5831\u3092\u8868\u793a\u3057\u307e\u3059\u3002
\ No newline at end of file
diff --git a/core/src/main/resources/hudson/PluginManager/advanced.jelly b/core/src/main/resources/hudson/PluginManager/advanced.jelly
index 904d3d6c1f..ceb464948f 100644
--- a/core/src/main/resources/hudson/PluginManager/advanced.jelly
+++ b/core/src/main/resources/hudson/PluginManager/advanced.jelly
@@ -41,7 +41,8 @@ THE SOFTWARE.
                 <f:textbox name="proxy.server" value="${app.proxy.name}" />
               </f:entry>
               <f:entry title="${%Port}" help="/help/update-center/proxy-port.html">
-                <f:textbox name="proxy.port" value="${app.proxy.port}" />
+                <f:textbox name="proxy.port" value="${app.proxy.port}" 
+                           checkUrl="'${rootURL}/pluginManager/checkProxyPort?value='+escape(this.value)" />
               </f:entry>
             </f:block>
             <f:entry title="${%User name}" help="/help/update-center/proxy-username.html">