split nftables.conf to ip and ip6 instead of inet

config/etc/nftables.conf

@@ -2,42 +2,70 @@
 
 flush ruleset
 
-table inet filter {
-    chain input {
+# don't use inet instead of ip&ip6,
+# because Docker doesn't support it, yet
+# see https://maximilianehlers.com/blog/nftables-and-docker/ for more details
+
+table ip filter {
+    chain INPUT {
         type filter hook input priority 0;
         policy drop;
 
 
         # allow already established connections (e.g. initiated by this host)
-        ct state related,established counter accept
+        ct state related,established accept
 
         # allow ICMP
-        ip protocol icmp counter accept
+        ip protocol icmp accept
 
         # allow anything on localhost
-        iifname "lo" counter accept
+        iifname "lo" accept
 
         # allow SSH for remote management
-        tcp dport 22 counter accept
+        tcp dport 22 accept
 
 
         ## docker
 
         # cluster management communications
-        tcp dport 2377 counter accept
+        tcp dport 2377 accept
 
         # communication among nodes
-        tcp dport 7946 counter accept
-        udp dport 7946 counter accept
+        tcp dport 7946 accept
+        udp dport 7946 accept
 
         # overlay network traffic
-        udp dport 4789 counter accept
+        udp dport 4789 accept
     }
-    chain forward {
+    chain FORWARD {
         type filter hook forward priority 0;
         policy drop;
     }
-    chain output {
+    chain OUTPUT {
+        type filter hook output priority 0;
+        policy accept;
+    }
+}
+table ip6 filter {
+    chain INPUT {
+        type filter hook input priority 0;
+        policy drop;
+
+
+        # allow already established connections (e.g. initiated by this host)
+        ct state related,established accept
+
+        # allow ICMPv6
+        ip6 nexthdr icmpv6 accept
+
+        # allow anything on localhost
+        iifname "lo" accept
+    }
+    chain FORWARD {
+        type filter hook forward priority 0;
+        policy drop;
+    }
+    chain OUTPUT {
         type filter hook output priority 0;
         policy accept;
     }