Added documentation about the DISABLE_IPV6 environment variable.

Dockerfile

@@ -275,7 +275,8 @@ COPY rootfs/ /
 
 # Set environment variables.
 ENV APP_NAME="Nginx Proxy Manager" \
-    KEEP_APP_RUNNING=1
+    KEEP_APP_RUNNING=1 \
+    DISABLE_IPV6=0
 
 # Define mountable directories.
 VOLUME ["/config"]

README.md

@@ -88,6 +88,7 @@ of this parameter has the format `<VARIABLE_NAME>=<VALUE>`.
 |`KEEP_APP_RUNNING`| When set to `1`, the application will be automatically restarted if it crashes or if a user quits it. | `0` |
 |`APP_NICENESS`| Priority at which the application should run.  A niceness value of -20 is the highest priority and 19 is the lowest priority.  By default, niceness is not set, meaning that the default niceness of 0 is used.  **NOTE**: A negative niceness (priority increase) requires additional permissions.  In this case, the container should be run with the docker option `--cap-add=SYS_NICE`. | (unset) |
 |`CLEAN_TMP_DIR`| When set to `1`, all files in the `/tmp` directory are deleted during the container startup. | `1` |
+|`DISABLE_IPV6`| When set to `1`, IPv6 support is disabled.  This is needed when IPv6 is not enabled/supported on the host. | `0` |
 
 ### Data Volumes
 

appdefs.xml

@@ -257,7 +257,20 @@ Where:
   </app>
   <container>
     <!-- Environment variables -->
-    <environment_variables/>
+    <environment_variables>
+      <environment_variable>
+        <name>DISABLE_IPV6</name>
+        <description>When set to `1`, IPv6 support is disabled.  This is needed when IPv6 is not enabled/supported on the host.</description>
+        <default>0</default>
+        <unraid_template>
+          <title>Automatic Video Converter: Preset</title>
+          <description>When set to '1', IPv6 support is disabled.</description>
+          <display>advanced</display>
+          <required>false</required>
+          <mask>false</mask>
+        </unraid_template>
+      </environment_variable>
+    </environment_variables>
     <!-- Volumes -->
     <volumes/>
     <!-- Network ports -->