diff --git a/container.json b/container.json
index 875b73e..93709d9 100644
--- a/container.json
+++ b/container.json
@@ -38,7 +38,6 @@
       "lxc": false
     },
     "jabber": {
-      "ipv4": "192.168.66.22/32",
       "ipv6": "2a01:4f8:210:31fd:1::16/128",
       "rdns6": "jabber.higgsboson.tk",
       "lxc": false
@@ -69,6 +68,7 @@
     "ns1": {
       "ns": true,
       "lxc": false,
+      "rdns6": "ns1.higgsboson.tk",
       "ipv4": "192.168.66.6/32",
       "ipv6": "2a01:4f8:210:31fd:1::6/128"
     },
@@ -81,7 +81,7 @@
     "dns": {
       "ipv4": "192.168.66.6/32",
       "ipv6": "2a01:4f8:210:31fd:1::6/128",
-      "rdns6": "ns.higgsboson.tk",
+      "rdns6": "ns1.higgsboson.tk",
       "dn42": {
         "ipv4": "172.23.75.4"
       }
diff --git a/hooks/lib/lxc/hetzner.rb b/hooks/lib/lxc/hetzner.rb
index f40a0f4..7182b5f 100644
--- a/hooks/lib/lxc/hetzner.rb
+++ b/hooks/lib/lxc/hetzner.rb
@@ -41,16 +41,14 @@ module Lxc
 
     def perform_request(req)
       req.basic_auth(@user, @password)
-      resp = Net::HTTP.start(BASE_URI.hostname,
-                             BASE_URI.port,
-                             use_ssl: true) do |http|
-                               http.request(req)
-                             end
-                             if resp.code.start_with? "2"
-                               return resp
-                             else
-                               raise StandardError.new("failed to perform request: #{resp.inspect}")
-                             end
+      resp = Net::HTTP.start(BASE_URI.hostname, BASE_URI.port, use_ssl: true) do |http|
+        http.request(req)
+      end
+      if resp.code.start_with? "2"
+        return resp
+      else
+        raise StandardError.new("failed to perform request for '#{req.path}': #{resp.code} - #{resp.body}")
+      end
     end
   end
 end
diff --git a/hooks/update-hetzner-rdns b/hooks/update-hetzner-rdns
index 39be4b2..57cace3 100755
--- a/hooks/update-hetzner-rdns
+++ b/hooks/update-hetzner-rdns
@@ -1,35 +1,51 @@
 #!/usr/bin/env ruby
 require "netaddr"
+require "set"
 require_relative "lib/lxc"
 
-def update_hetzner_rdns6(user, password, domain, network)
+def update_hetzner_rdns6(user, password, domain, subnet, network)
   api = Lxc::Hetzner.new(user, password)
   rdns = api.get("/rdns")
   records = {}
   rdns.each do |val|
     rec = val["rdns"]
     cidr = NetAddr::CIDR.create(rec["ip"])
-    next if cidr.version == 4
-    records[cidr.ip] = rec["ptr"]
+    next unless cidr.version == 6 and subnet.contains?(rec["ip"])
+    records[rec["ip"]] = rec["ptr"]
   end
+  processed_ips = Set.new
+
   network.each do |host, data|
     cidr = data["ipv6"]
     next if cidr.nil?
-    ipv6 = NetAddr::CIDR.create(cidr).ip
+    cidr = NetAddr::CIDR.create(cidr)
+    next unless cidr.version == 6 and subnet.contains?(data["ipv6"])
     hostname = data["rdns6"] || "#{host}.#{domain}"
-    ptr = records.delete(ipv6)
+    ip = cidr.ip(Short: true)
+    next if processed_ips.include?(ip)
+    processed_ips << ip
+    ptr = records.delete(ip)
     if ptr.nil? or ptr != hostname
-      api.post("/rdns/#{ipv6}", ptr: hostname)
+      puts "add ptr: #{ip} -> #{hostname}"
+      api.post("/rdns/#{ip}", ptr: hostname)
     end
   end
   records.each do |ip, ptr|
+    puts "delete ptr: #{ip} -> #{ptr}"
     api.delete("/rnds/#{ip}")
   end
 end
 
-credentials = File.read(Lxc::CONFIG_ROOT.join("hetzner.key"))
-user, password = credentials.split(":")
 registry = Lxc::Registry.new
 registry.data["zone"] ||= {}
-domain = registry.data["zone"]["domain"]
-update_hetzner_rdns6(user, password, domain, registry.data["network"] || {})
+domain = registry.data["zone"]["domain"] || "lxc"
+subnet = registry.data["zone"]["v6_subnet"]
+if subnet
+  subnet_cidr = NetAddr::CIDR.create(subnet)
+  credentials = File.read(Lxc::CONFIG_ROOT.join("hetzner.key"))
+  user, password = credentials.split(":")
+  network = registry.data["network"] || {}
+  update_hetzner_rdns6(user, password, domain, subnet_cidr, network)
+else
+  puts "no v6_subnet specified in container.json. skip rdns records"
+end