diff --git a/smack-core/src/main/java/org/jivesoftware/smack/util/dns/HostAddress.java b/smack-core/src/main/java/org/jivesoftware/smack/util/dns/HostAddress.java
index e0eb98aed..e56b0a185 100644
--- a/smack-core/src/main/java/org/jivesoftware/smack/util/dns/HostAddress.java
+++ b/smack-core/src/main/java/org/jivesoftware/smack/util/dns/HostAddress.java
@@ -1,6 +1,6 @@
 /**
  *
- * Copyright © 2013-2016 Florian Schmaus
+ * Copyright © 2013-2017 Florian Schmaus
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,7 +25,7 @@ import java.util.Map;
 import java.util.Map.Entry;
 
 import org.jivesoftware.smack.SmackException.ConnectionException;
-import org.jivesoftware.smack.util.Objects;
+import org.jivesoftware.smack.util.StringUtils;
 
 public class HostAddress {
     private final String fqdn;
@@ -34,18 +34,17 @@ public class HostAddress {
     private final List<InetAddress> inetAddresses;
 
     /**
-     * Creates a new HostAddress with the given FQDN. The port will be set to the default XMPP client port: 5222
+     * Creates a new HostAddress with the given FQDN.
      * 
-     * @param fqdn Fully qualified domain name.
+     * @param fqdn the optional fully qualified domain name (FQDN).
      * @param port The port to connect on.
-     * @throws IllegalArgumentException If the fqdn is null or port is out of valid range (0 - 65535).
+     * @throws IllegalArgumentException If the port is out of valid range (0 - 65535).
      */
     public HostAddress(String fqdn, int port, List<InetAddress> inetAddresses) {
-        Objects.requireNonNull(fqdn, "FQDN is null");
         if (port < 0 || port > 65535)
             throw new IllegalArgumentException(
                     "Port must be a 16-bit unsiged integer (i.e. between 0-65535. Port was: " + port);
-        if (fqdn.charAt(fqdn.length() - 1) == '.') {
+        if (StringUtils.isNotEmpty(fqdn) && fqdn.charAt(fqdn.length() - 1) == '.') {
             this.fqdn = fqdn.substring(0, fqdn.length() - 1);
         }
         else {
@@ -59,7 +58,7 @@ public class HostAddress {
     }
 
     public HostAddress(int port, InetAddress hostAddress) {
-        this("", port, Collections.singletonList(hostAddress));
+        this(null, port, Collections.singletonList(hostAddress));
     }
 
     /**
diff --git a/smack-core/src/main/java/org/jivesoftware/smack/util/dns/SRVRecord.java b/smack-core/src/main/java/org/jivesoftware/smack/util/dns/SRVRecord.java
index e84d846de..f63c94e49 100644
--- a/smack-core/src/main/java/org/jivesoftware/smack/util/dns/SRVRecord.java
+++ b/smack-core/src/main/java/org/jivesoftware/smack/util/dns/SRVRecord.java
@@ -1,6 +1,6 @@
 /**
  *
- * Copyright 2013-2016 Florian Schmaus
+ * Copyright 2013-2017 Florian Schmaus
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,8 @@ package org.jivesoftware.smack.util.dns;
 import java.net.InetAddress;
 import java.util.List;
 
+import org.jivesoftware.smack.util.StringUtils;
+
 /**
  * A DNS SRV RR.
  *
@@ -43,6 +45,7 @@ public class SRVRecord extends HostAddress implements Comparable<SRVRecord> {
      */
     public SRVRecord(String fqdn, int port, int priority, int weight, List<InetAddress> inetAddresses) {
         super(fqdn, port, inetAddresses);
+        StringUtils.requireNotNullOrEmpty(fqdn, "The FQDN must not be null");
         if (weight < 0 || weight > 65535)
             throw new IllegalArgumentException(
                     "DNS SRV records weight must be a 16-bit unsiged integer (i.e. between 0-65535. Weight was: "
diff --git a/smack-tcp/src/main/java/org/jivesoftware/smack/tcp/XMPPTCPConnection.java b/smack-tcp/src/main/java/org/jivesoftware/smack/tcp/XMPPTCPConnection.java
index 61fe86a3b..2080c100a 100644
--- a/smack-tcp/src/main/java/org/jivesoftware/smack/tcp/XMPPTCPConnection.java
+++ b/smack-tcp/src/main/java/org/jivesoftware/smack/tcp/XMPPTCPConnection.java
@@ -593,6 +593,7 @@ public class XMPPTCPConnection extends AbstractXMPPConnection {
                 }
                 failedAddresses.add(hostAddress);
             } else {
+                StringUtils.requireNotNullOrEmpty(host, "Host of HostAddress " + hostAddress + " must not be null when using a Proxy");
                 final String hostAndPort = host + " at port " + port;
                 LOGGER.finer("Trying to establish TCP connection via Proxy to " + hostAndPort);
                 try {