@@ -848,6 +848,7 @@ public HostConfig withMemorySwappiness(Long memorySwappiness) {
      * <li>'host': use the host network stack inside the container. Note: the host mode gives the container full access to local system
      * services such as D-bus and is therefore considered insecure.</li>
      * </ul>
+     * Any other value is interpreted as a custom network's name for this container to connect to.
      */
     public HostConfig withNetworkMode(String networkMode) {
         this.networkMode = networkMode;
 
@@ -600,7 +600,7 @@ public CreateContainerResponse exec() throws NotFoundException, ConflictExceptio
             containerNetwork.withAliases(aliases);
         }
 
-        if (containerNetwork != null) {
+        if (containerNetwork != null && hostConfig.getNetworkMode() != null) {
             networkingConfig = new NetworkingConfig()
                     .withEndpointsConfig(singletonMap(hostConfig.getNetworkMode(), containerNetwork));
         }
 
@@ -23,6 +23,7 @@
 import com.github.dockerjava.api.model.Link;
 import com.github.dockerjava.api.model.LogConfig;
 import com.github.dockerjava.api.model.Network;
+import com.github.dockerjava.api.model.PortBinding;
 import com.github.dockerjava.api.model.Ports;
 import com.github.dockerjava.api.model.Ports.Binding;
 import com.github.dockerjava.api.model.RestartPolicy;
@@ -1125,4 +1126,15 @@ public void shouldNotEncodeAuth() {
 
         assertThat(jsonNode.get("authConfig"), nullValue());
     }
+
+    @Test
+    public void shouldHandleANetworkAliasWithoutACustomNetworkGracefully() {
+        // Should not throw
+        dockerRule.getClient()
+            .createContainerCmd(DEFAULT_IMAGE)
+            .withAliases("hello-world")
+            .withHostConfig(newHostConfig())
+            .withCmd("sleep", "9999")
+            .exec();
+    }
 }
Original file line number	Diff line number	Diff line change
@@ -600,7 +600,7 @@ public CreateContainerResponse exec() throws NotFoundException, ConflictExceptio
600	600	containerNetwork.withAliases(aliases);
601	601	}
602	602
603		- if (containerNetwork != null) {
	603	+ if (containerNetwork != null && hostConfig.getNetworkMode() != null) {
604	604	networkingConfig = new NetworkingConfig()
605	605	.withEndpointsConfig(singletonMap(hostConfig.getNetworkMode(), containerNetwork));
606	606	}