diff --git a/Dockerfile b/Dockerfile
index 4836674..1d97dfe 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -12,5 +12,7 @@ RUN apt-get -q -y update \
  && apt-get -q -y clean \
  && rm -rf /var/lib/apt/lists/*
 
+ENV DHCPD_PROTOCOL=4
+
 COPY util/entrypoint.sh /entrypoint.sh
 ENTRYPOINT ["/entrypoint.sh"]
diff --git a/Dockerfile.ldap b/Dockerfile.ldap
index deaabd6..52048af 100644
--- a/Dockerfile.ldap
+++ b/Dockerfile.ldap
@@ -12,5 +12,7 @@ RUN apt-get -q -y update \
  && apt-get -q -y clean \
  && rm -rf /var/lib/apt/lists/*
 
+ENV DHCPD_PROTOCOL=4
+
 COPY util/entrypoint.sh /entrypoint.sh
 ENTRYPOINT ["/entrypoint.sh"]
diff --git a/README.md b/README.md
index 2590fe8..d5078bd 100644
--- a/README.md
+++ b/README.md
@@ -34,6 +34,14 @@ on.
 A simple `run` script is also included which makes it quick to iterate on a
 configuration until you're satisfied.
 
+DHCPv6
+------
+
+To use a DHCPv6-Server you have to pass `DHCPD_PROTOCOL=6` as enviroment variable
+
+`docker run -it --rm --init -e DHCPD_PROTOCOL=6 --net host -v "$(pwd)/data":/data networkboot/dhcpd eth0`
+
+
 Notes
 =====
 
diff --git a/util/entrypoint.sh b/util/entrypoint.sh
index 1a8f59b..63883fd 100755
--- a/util/entrypoint.sh
+++ b/util/entrypoint.sh
@@ -69,7 +69,7 @@ if [ -n "$IFACE" ]; then
         echo "You must add the 'docker run' option '--net=host' if you want to provide DHCP service to the host network."
     fi
 
-    $run /usr/sbin/dhcpd -4 -f -d --no-pid -cf "$data_dir/dhcpd.conf" -lf "$data_dir/dhcpd.leases" $IFACE
+    $run /usr/sbin/dhcpd -$DHCPD_PROTOCOL -f -d --no-pid -cf "$data_dir/dhcpd.conf" -lf "$data_dir/dhcpd.leases" $IFACE
 else
     # Run another binary
     $run "$@"