diff --git a/README.md b/README.md
index 7f99c71..916d466 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,5 @@
 # ConfigServer Security & Firewall (CSF) - Docker
+
+Install: 
+
+cp csfpost.sh /usr/local/csf/bin/csfpost.sh
diff --git a/csfpost.sh b/csfpost.sh
index 839be05..c7640c2 100644
--- a/csfpost.sh
+++ b/csfpost.sh
@@ -1,8 +1,23 @@
 #!/bin/bash
 
+chain_exists()
+{
+    [ $# -lt 1 -o $# -gt 2 ] && { 
+        echo "Usage: chain_exists <chain_name> [table]" >&2
+        return 1
+    }
+    local chain_name="$1" ; shift
+    [ $# -eq 1 ] && local table="--table $1"
+    iptables $table -n --list "$chain_name" >/dev/null 2>&1
+}
+
 DOCKER_INT="docker0"
 DOCKER_NETWORK="172.17.0.0/16"
 
+iptables-save | grep -v -- '-j DOCKER' | iptables-restore
+chain_exists DOCKER && iptables -X DOCKER
+chain_exists DOCKER nat && iptables -t nat -X DOCKER
+
 iptables -N DOCKER
 iptables -t nat -N DOCKER