first

data/Dockerfiles/netfilter/Dockerfile

@@ -0,0 +1,43 @@
+FROM alpine:3.20
+
+LABEL maintainer = "The Infrastructure Company GmbH <info@servercow.de>"
+
+WORKDIR /app
+
+ARG PIP_BREAK_SYSTEM_PACKAGES=1
+ENV XTABLES_LIBDIR /usr/lib/xtables
+ENV PYTHON_IPTABLES_XTABLES_VERSION 12
+ENV IPTABLES_LIBDIR /usr/lib
+
+RUN apk add --virtual .build-deps \
+  gcc \
+  python3-dev \
+  libffi-dev \
+  openssl-dev \
+&& apk add -U python3 \
+  iptables \
+  iptables-dev \
+  ip6tables \
+  xtables-addons \
+  nftables \
+  tzdata \
+  py3-pip \
+  py3-nftables \
+  musl-dev \
+&& pip3 install --ignore-installed --upgrade pip \
+  jsonschema \
+  python-iptables \
+  redis \
+  ipaddress \
+  dnspython \
+&& apk del .build-deps
+
+#  && pip3 install --upgrade pip python-iptables==0.13.0 redis ipaddress dnspython \
+
+COPY modules /app/modules
+COPY main.py /app/
+COPY ./docker-entrypoint.sh /app/
+
+RUN chmod +x /app/docker-entrypoint.sh
+
+CMD ["/bin/sh", "-c", "/app/docker-entrypoint.sh"]

data/Dockerfiles/netfilter/docker-entrypoint.sh

@@ -0,0 +1,29 @@
+#!/bin/sh
+
+backend=iptables
+
+nft list table ip filter &>/dev/null
+nftables_found=$?
+
+iptables -L -n &>/dev/null
+iptables_found=$?
+
+if [ $nftables_found -lt $iptables_found ]; then
+  backend=nftables
+fi
+
+if [ $nftables_found -gt $iptables_found ]; then
+  backend=iptables
+fi
+
+if [ $nftables_found -eq 0 ] && [ $nftables_found -eq $iptables_found ]; then
+  nftables_lines=$(nft list ruleset | wc -l)
+  iptables_lines=$(iptables-save | wc -l)
+  if [ $nftables_lines -gt $iptables_lines ]; then
+    backend=nftables
+  else
+    backend=iptables
+  fi
+fi
+
+exec python -u /app/main.py $backend

data/Dockerfiles/netfilter/main.py

@@ -0,0 +1,503 @@
+#!/usr/bin/env python3
+
+import re
+import os
+import sys
+import time
+import atexit
+import signal
+import ipaddress
+from collections import Counter
+from random import randint
+from threading import Thread
+from threading import Lock
+import redis
+import json
+import dns.resolver
+import dns.exception
+import uuid
+from modules.Logger import Logger
+from modules.IPTables import IPTables
+from modules.NFTables import NFTables
+
+
+# globals
+WHITELIST = []
+BLACKLIST= []
+bans = {}
+quit_now = False
+exit_code = 0
+lock = Lock()
+chain_name = "MAILCOW"
+r = None
+pubsub = None
+clear_before_quit = False
+
+
+def refreshF2boptions():
+  global f2boptions
+  global quit_now
+  global exit_code
+
+  f2boptions = {}
+
+  if not r.get('F2B_OPTIONS'):
+    f2boptions['ban_time'] = r.get('F2B_BAN_TIME')
+    f2boptions['max_ban_time'] = r.get('F2B_MAX_BAN_TIME')
+    f2boptions['ban_time_increment'] = r.get('F2B_BAN_TIME_INCREMENT')
+    f2boptions['max_attempts'] = r.get('F2B_MAX_ATTEMPTS')
+    f2boptions['retry_window'] = r.get('F2B_RETRY_WINDOW')
+    f2boptions['netban_ipv4'] = r.get('F2B_NETBAN_IPV4')
+    f2boptions['netban_ipv6'] = r.get('F2B_NETBAN_IPV6')
+  else:
+    try:
+      f2boptions = json.loads(r.get('F2B_OPTIONS'))
+    except ValueError:
+      logger.logCrit('Error loading F2B options: F2B_OPTIONS is not json')
+      quit_now = True
+      exit_code = 2
+
+  verifyF2boptions(f2boptions)
+  r.set('F2B_OPTIONS', json.dumps(f2boptions, ensure_ascii=False))
+
+def verifyF2boptions(f2boptions):
+  verifyF2boption(f2boptions,'ban_time', 1800)
+  verifyF2boption(f2boptions,'max_ban_time', 10000)
+  verifyF2boption(f2boptions,'ban_time_increment', True)
+  verifyF2boption(f2boptions,'max_attempts', 10)
+  verifyF2boption(f2boptions,'retry_window', 600)
+  verifyF2boption(f2boptions,'netban_ipv4', 32)
+  verifyF2boption(f2boptions,'netban_ipv6', 128)
+  verifyF2boption(f2boptions,'banlist_id', str(uuid.uuid4()))
+  verifyF2boption(f2boptions,'manage_external', 0)
+
+def verifyF2boption(f2boptions, f2boption, f2bdefault):
+  f2boptions[f2boption] = f2boptions[f2boption] if f2boption in f2boptions and f2boptions[f2boption] is not None else f2bdefault
+
+def refreshF2bregex():
+  global f2bregex
+  global quit_now
+  global exit_code
+  if not r.get('F2B_REGEX'):
+    f2bregex = {}
+    f2bregex[1] = r'mailcow UI: Invalid password for .+ by ([0-9a-f\.:]+)'
+    f2bregex[2] = r'Rspamd UI: Invalid password by ([0-9a-f\.:]+)'
+    f2bregex[3] = r'warning: .*\[([0-9a-f\.:]+)\]: SASL .+ authentication failed: (?!.*Connection lost to authentication server).+'
+    f2bregex[4] = r'warning: non-SMTP command from .*\[([0-9a-f\.:]+)]:.+'
+    f2bregex[5] = r'NOQUEUE: reject: RCPT from \[([0-9a-f\.:]+)].+Protocol error.+'
+    f2bregex[6] = r'-login: Disconnected.+ \(auth failed, .+\): user=.*, method=.+, rip=([0-9a-f\.:]+),'
+    f2bregex[7] = r'-login: Aborted login.+ \(auth failed .+\): user=.+, rip=([0-9a-f\.:]+), lip.+'
+    f2bregex[8] = r'-login: Aborted login.+ \(tried to use disallowed .+\): user=.+, rip=([0-9a-f\.:]+), lip.+'
+    f2bregex[9] = r'SOGo.+ Login from \'([0-9a-f\.:]+)\' for user .+ might not have worked'
+    f2bregex[10] = r'([0-9a-f\.:]+) \"GET \/SOGo\/.* HTTP.+\" 403 .+'
+    r.set('F2B_REGEX', json.dumps(f2bregex, ensure_ascii=False))
+  else:
+    try:
+      f2bregex = {}
+      f2bregex = json.loads(r.get('F2B_REGEX'))
+    except ValueError:
+      logger.logCrit('Error loading F2B options: F2B_REGEX is not json')
+      quit_now = True
+      exit_code = 2
+
+def get_ip(address):
+  ip = ipaddress.ip_address(address)
+  if type(ip) is ipaddress.IPv6Address and ip.ipv4_mapped:
+    ip = ip.ipv4_mapped
+  if ip.is_private or ip.is_loopback:
+    return False
+  
+  return ip
+
+def ban(address):
+  global f2boptions
+  global lock
+
+  refreshF2boptions()
+  MAX_ATTEMPTS = int(f2boptions['max_attempts'])
+  RETRY_WINDOW = int(f2boptions['retry_window'])
+  NETBAN_IPV4 = '/' + str(f2boptions['netban_ipv4'])
+  NETBAN_IPV6 = '/' + str(f2boptions['netban_ipv6'])
+
+  ip = get_ip(address)
+  if not ip: return
+  address = str(ip)
+  self_network = ipaddress.ip_network(address)
+
+  with lock:
+    temp_whitelist = set(WHITELIST)
+  if temp_whitelist:
+    for wl_key in temp_whitelist:
+      wl_net = ipaddress.ip_network(wl_key, False)
+      if wl_net.overlaps(self_network):
+        logger.logInfo('Address %s is whitelisted by rule %s' % (self_network, wl_net))
+        return
+
+  net = ipaddress.ip_network((address + (NETBAN_IPV4 if type(ip) is ipaddress.IPv4Address else NETBAN_IPV6)), strict=False)
+  net = str(net)
+
+  if not net in bans:
+    bans[net] = {'attempts': 0, 'last_attempt': 0, 'ban_counter': 0}
+
+  current_attempt = time.time()
+  if current_attempt - bans[net]['last_attempt'] > RETRY_WINDOW:
+    bans[net]['attempts'] = 0
+
+  bans[net]['attempts'] += 1
+  bans[net]['last_attempt'] = current_attempt
+
+  if bans[net]['attempts'] >= MAX_ATTEMPTS:
+    cur_time = int(round(time.time()))
+    NET_BAN_TIME = calcNetBanTime(bans[net]['ban_counter'])
+    logger.logCrit('Banning %s for %d minutes' % (net, NET_BAN_TIME / 60 ))
+    if type(ip) is ipaddress.IPv4Address and int(f2boptions['manage_external']) != 1:
+      with lock:
+        tables.banIPv4(net)
+    elif int(f2boptions['manage_external']) != 1:
+      with lock:
+        tables.banIPv6(net)
+
+    r.hset('F2B_ACTIVE_BANS', '%s' % net, cur_time + NET_BAN_TIME)
+  else:
+    logger.logWarn('%d more attempts in the next %d seconds until %s is banned' % (MAX_ATTEMPTS - bans[net]['attempts'], RETRY_WINDOW, net))
+
+def unban(net):
+  global lock
+
+  if not net in bans:
+   logger.logInfo('%s is not banned, skipping unban and deleting from queue (if any)' % net)
+   r.hdel('F2B_QUEUE_UNBAN', '%s' % net)
+   return
+
+  logger.logInfo('Unbanning %s' % net)
+  if type(ipaddress.ip_network(net)) is ipaddress.IPv4Network:
+    with lock:
+      tables.unbanIPv4(net)
+  else:
+    with lock:
+      tables.unbanIPv6(net)
+
+  r.hdel('F2B_ACTIVE_BANS', '%s' % net)
+  r.hdel('F2B_QUEUE_UNBAN', '%s' % net)
+  if net in bans:
+    bans[net]['attempts'] = 0
+    bans[net]['ban_counter'] += 1
+
+def permBan(net, unban=False):
+  global f2boptions
+  global lock
+
+  is_unbanned = False
+  is_banned = False
+  if type(ipaddress.ip_network(net, strict=False)) is ipaddress.IPv4Network:
+    with lock:
+      if unban:
+        is_unbanned = tables.unbanIPv4(net)
+      elif int(f2boptions['manage_external']) != 1:
+        is_banned = tables.banIPv4(net)
+  else:
+    with lock:
+      if unban:
+        is_unbanned = tables.unbanIPv6(net)
+      elif int(f2boptions['manage_external']) != 1:
+        is_banned = tables.banIPv6(net)
+
+
+  if is_unbanned:
+    r.hdel('F2B_PERM_BANS', '%s' % net)
+    logger.logCrit('Removed host/network %s from blacklist' % net)
+  elif is_banned:
+    r.hset('F2B_PERM_BANS', '%s' % net, int(round(time.time())))
+    logger.logCrit('Added host/network %s to blacklist' % net)
+
+def clear():
+  global lock
+  logger.logInfo('Clearing all bans')
+  for net in bans.copy():
+    unban(net)
+  with lock:
+    tables.clearIPv4Table()
+    tables.clearIPv6Table()
+    try:
+      if r is not None:
+        r.delete('F2B_ACTIVE_BANS')
+        r.delete('F2B_PERM_BANS')
+    except Exception as ex:
+      logger.logWarn('Error clearing redis keys F2B_ACTIVE_BANS and F2B_PERM_BANS: %s' % ex)
+
+def watch():
+  global pubsub
+  global quit_now
+  global exit_code
+
+  logger.logInfo('Watching Redis channel F2B_CHANNEL')
+  pubsub.subscribe('F2B_CHANNEL')
+
+  while not quit_now:
+    try:
+      for item in pubsub.listen():
+        refreshF2bregex()
+        for rule_id, rule_regex in f2bregex.items():
+          if item['data'] and item['type'] == 'message':
+            try:
+              result = re.search(rule_regex, item['data'])
+            except re.error:
+              result = False
+            if result:
+              addr = result.group(1)
+              ip = ipaddress.ip_address(addr)
+              if ip.is_private or ip.is_loopback:
+                continue
+              logger.logWarn('%s matched rule id %s (%s)' % (addr, rule_id, item['data']))
+              ban(addr)
+    except Exception as ex:
+      logger.logWarn('Error reading log line from pubsub: %s' % ex)
+      pubsub = None
+      quit_now = True
+      exit_code = 2
+
+def snat4(snat_target):
+  global lock
+  global quit_now
+
+  while not quit_now:
+    time.sleep(10)
+    with lock:
+      tables.snat4(snat_target, os.getenv('IPV4_NETWORK', '172.22.1') + '.0/24')
+
+def snat6(snat_target):
+  global lock
+  global quit_now
+
+  while not quit_now:
+    time.sleep(10)
+    with lock:
+      tables.snat6(snat_target, os.getenv('IPV6_NETWORK', 'fd4d:6169:6c63:6f77::/64'))
+
+def autopurge():
+  global f2boptions
+
+  while not quit_now:
+    time.sleep(10)
+    refreshF2boptions()
+    MAX_ATTEMPTS = int(f2boptions['max_attempts'])
+    QUEUE_UNBAN = r.hgetall('F2B_QUEUE_UNBAN')
+    if QUEUE_UNBAN:
+      for net in QUEUE_UNBAN:
+        unban(str(net))
+    for net in bans.copy():
+      if bans[net]['attempts'] >= MAX_ATTEMPTS:
+        NET_BAN_TIME = calcNetBanTime(bans[net]['ban_counter'])
+        TIME_SINCE_LAST_ATTEMPT = time.time() - bans[net]['last_attempt']
+        if TIME_SINCE_LAST_ATTEMPT > NET_BAN_TIME:
+          unban(net)
+
+def mailcowChainOrder():
+  global lock
+  global quit_now
+  global exit_code
+  while not quit_now:
+    time.sleep(10)
+    with lock:
+      quit_now, exit_code = tables.checkIPv4ChainOrder()
+      if quit_now: return
+      quit_now, exit_code = tables.checkIPv6ChainOrder()
+
+def calcNetBanTime(ban_counter):
+  global f2boptions
+
+  BAN_TIME = int(f2boptions['ban_time'])
+  MAX_BAN_TIME = int(f2boptions['max_ban_time'])
+  BAN_TIME_INCREMENT = bool(f2boptions['ban_time_increment'])
+  NET_BAN_TIME = BAN_TIME if not BAN_TIME_INCREMENT else BAN_TIME * 2 ** ban_counter
+  NET_BAN_TIME = max([BAN_TIME, min([NET_BAN_TIME, MAX_BAN_TIME])])
+  return NET_BAN_TIME
+
+def isIpNetwork(address):
+  try:
+    ipaddress.ip_network(address, False)
+  except ValueError:
+    return False
+  return True
+
+def genNetworkList(list):
+  resolver = dns.resolver.Resolver()
+  hostnames = []
+  networks = []
+  for key in list:
+    if isIpNetwork(key):
+      networks.append(key)
+    else:
+      hostnames.append(key)
+  for hostname in hostnames:
+    hostname_ips = []
+    for rdtype in ['A', 'AAAA']:
+      try:
+        answer = resolver.resolve(qname=hostname, rdtype=rdtype, lifetime=3)
+      except dns.exception.Timeout:
+        logger.logInfo('Hostname %s timedout on resolve' % hostname)
+        break
+      except (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
+        continue
+      except dns.exception.DNSException as dnsexception:
+        logger.logInfo('%s' % dnsexception)
+        continue
+      for rdata in answer:
+        hostname_ips.append(rdata.to_text())
+    networks.extend(hostname_ips)
+  return set(networks)
+
+def whitelistUpdate():
+  global lock
+  global quit_now
+  global WHITELIST
+  while not quit_now:
+    start_time = time.time()
+    list = r.hgetall('F2B_WHITELIST')
+    new_whitelist = []
+    if list:
+      new_whitelist = genNetworkList(list)
+    with lock:
+      if Counter(new_whitelist) != Counter(WHITELIST):
+        WHITELIST = new_whitelist
+        logger.logInfo('Whitelist was changed, it has %s entries' % len(WHITELIST))
+    time.sleep(60.0 - ((time.time() - start_time) % 60.0))
+
+def blacklistUpdate():
+  global quit_now
+  global BLACKLIST
+  while not quit_now:
+    start_time = time.time()
+    list = r.hgetall('F2B_BLACKLIST')
+    new_blacklist = []
+    if list:
+      new_blacklist = genNetworkList(list)
+    if Counter(new_blacklist) != Counter(BLACKLIST):
+      addban = set(new_blacklist).difference(BLACKLIST)
+      delban = set(BLACKLIST).difference(new_blacklist)
+      BLACKLIST = new_blacklist
+      logger.logInfo('Blacklist was changed, it has %s entries' % len(BLACKLIST))
+      if addban:
+        for net in addban:
+          permBan(net=net)
+      if delban:
+        for net in delban:
+          permBan(net=net, unban=True)
+    time.sleep(60.0 - ((time.time() - start_time) % 60.0))
+
+def sigterm_quit(signum, frame):
+  global clear_before_quit
+  clear_before_quit = True
+  sys.exit(exit_code)
+
+def berfore_quit():
+  if clear_before_quit:
+    clear()
+  if pubsub is not None:
+    pubsub.unsubscribe()
+
+
+if __name__ == '__main__':
+  atexit.register(berfore_quit)
+  signal.signal(signal.SIGTERM, sigterm_quit)
+
+  # init Logger
+  logger = Logger()
+
+  # init backend
+  backend = sys.argv[1]
+  if backend == "nftables":
+    logger.logInfo('Using NFTables backend')
+    tables = NFTables(chain_name, logger)
+  else:
+    logger.logInfo('Using IPTables backend')
+    tables = IPTables(chain_name, logger)
+
+  # In case a previous session was killed without cleanup
+  clear()
+
+  # Reinit MAILCOW chain
+  # Is called before threads start, no locking
+  logger.logInfo("Initializing mailcow netfilter chain")
+  tables.initChainIPv4()
+  tables.initChainIPv6()
+
+  if os.getenv("DISABLE_NETFILTER_ISOLATION_RULE").lower() in ("y", "yes"):
+    logger.logInfo(f"Skipping {chain_name} isolation")
+  else:
+    logger.logInfo(f"Setting {chain_name} isolation")
+    tables.create_mailcow_isolation_rule("br-mailcow", [3306, 6379, 8983, 12345], os.getenv("MAILCOW_REPLICA_IP"))
+
+  # connect to redis
+  while True:
+    try:
+      redis_slaveof_ip = os.getenv('REDIS_SLAVEOF_IP', '')
+      redis_slaveof_port = os.getenv('REDIS_SLAVEOF_PORT', '')
+      if "".__eq__(redis_slaveof_ip):
+        r = redis.StrictRedis(host=os.getenv('IPV4_NETWORK', '172.22.1') + '.249', decode_responses=True, port=6379, db=0)
+      else:
+        r = redis.StrictRedis(host=redis_slaveof_ip, decode_responses=True, port=redis_slaveof_port, db=0)
+      r.ping()
+      pubsub = r.pubsub()
+    except Exception as ex:
+      print('%s - trying again in 3 seconds'  % (ex))
+      time.sleep(3)
+    else:
+      break
+  logger.set_redis(r)
+
+  # rename fail2ban to netfilter
+  if r.exists('F2B_LOG'):
+    r.rename('F2B_LOG', 'NETFILTER_LOG')
+  # clear bans in redis
+  r.delete('F2B_ACTIVE_BANS')
+  r.delete('F2B_PERM_BANS')
+  
+  refreshF2boptions()
+
+  watch_thread = Thread(target=watch)
+  watch_thread.daemon = True
+  watch_thread.start()
+
+  if os.getenv('SNAT_TO_SOURCE') and os.getenv('SNAT_TO_SOURCE') != 'n':
+    try:
+      snat_ip = os.getenv('SNAT_TO_SOURCE')
+      snat_ipo = ipaddress.ip_address(snat_ip)
+      if type(snat_ipo) is ipaddress.IPv4Address:
+        snat4_thread = Thread(target=snat4,args=(snat_ip,))
+        snat4_thread.daemon = True
+        snat4_thread.start()
+    except ValueError:
+      print(os.getenv('SNAT_TO_SOURCE') + ' is not a valid IPv4 address')
+
+  if os.getenv('SNAT6_TO_SOURCE') and os.getenv('SNAT6_TO_SOURCE') != 'n':
+    try:
+      snat_ip = os.getenv('SNAT6_TO_SOURCE')
+      snat_ipo = ipaddress.ip_address(snat_ip)
+      if type(snat_ipo) is ipaddress.IPv6Address:
+        snat6_thread = Thread(target=snat6,args=(snat_ip,))
+        snat6_thread.daemon = True
+        snat6_thread.start()
+    except ValueError:
+      print(os.getenv('SNAT6_TO_SOURCE') + ' is not a valid IPv6 address')
+
+  autopurge_thread = Thread(target=autopurge)
+  autopurge_thread.daemon = True
+  autopurge_thread.start()
+
+  mailcowchainwatch_thread = Thread(target=mailcowChainOrder)
+  mailcowchainwatch_thread.daemon = True
+  mailcowchainwatch_thread.start()
+
+  blacklistupdate_thread = Thread(target=blacklistUpdate)
+  blacklistupdate_thread.daemon = True
+  blacklistupdate_thread.start()
+
+  whitelistupdate_thread = Thread(target=whitelistUpdate)
+  whitelistupdate_thread.daemon = True
+  whitelistupdate_thread.start()
+
+  while not quit_now:
+    time.sleep(0.5)
+
+  sys.exit(exit_code)

data/Dockerfiles/netfilter/modules/IPTables.py

@@ -0,0 +1,252 @@
+import iptc
+import time
+import os
+
+class IPTables:
+  def __init__(self, chain_name, logger):
+    self.chain_name = chain_name
+    self.logger = logger
+
+  def initChainIPv4(self):
+    if not iptc.Chain(iptc.Table(iptc.Table.FILTER), self.chain_name) in iptc.Table(iptc.Table.FILTER).chains:
+      iptc.Table(iptc.Table.FILTER).create_chain(self.chain_name)
+    for c in ['FORWARD', 'INPUT']:
+      chain = iptc.Chain(iptc.Table(iptc.Table.FILTER), c)
+      rule = iptc.Rule()
+      rule.src = '0.0.0.0/0'
+      rule.dst = '0.0.0.0/0'
+      target = iptc.Target(rule, self.chain_name)
+      rule.target = target
+      if rule not in chain.rules:
+        chain.insert_rule(rule)
+
+  def initChainIPv6(self):
+    if not iptc.Chain(iptc.Table6(iptc.Table6.FILTER), self.chain_name) in iptc.Table6(iptc.Table6.FILTER).chains:
+      iptc.Table6(iptc.Table6.FILTER).create_chain(self.chain_name)
+    for c in ['FORWARD', 'INPUT']:
+      chain = iptc.Chain(iptc.Table6(iptc.Table6.FILTER), c)
+      rule = iptc.Rule6()
+      rule.src = '::/0'
+      rule.dst = '::/0'
+      target = iptc.Target(rule, self.chain_name)
+      rule.target = target
+      if rule not in chain.rules:
+        chain.insert_rule(rule)
+
+  def checkIPv4ChainOrder(self):
+    filter_table = iptc.Table(iptc.Table.FILTER)
+    filter_table.refresh()
+    return self.checkChainOrder(filter_table)
+
+  def checkIPv6ChainOrder(self):
+    filter_table = iptc.Table6(iptc.Table6.FILTER)
+    filter_table.refresh()
+    return self.checkChainOrder(filter_table)
+
+  def checkChainOrder(self, filter_table):
+    err = False
+    exit_code = None
+
+    forward_chain = iptc.Chain(filter_table, 'FORWARD')
+    input_chain = iptc.Chain(filter_table, 'INPUT')
+    for chain in [forward_chain, input_chain]:
+      target_found = False
+      for position, item in enumerate(chain.rules):
+        if item.target.name == self.chain_name:
+          target_found = True
+          if position > 2:
+            self.logger.logCrit('Error in %s chain: %s target not found, restarting container' % (chain.name, self.chain_name))
+            err = True
+            exit_code = 2
+      if not target_found:
+        self.logger.logCrit('Error in %s chain: %s target not found, restarting container' % (chain.name, self.chain_name))
+        err = True
+        exit_code = 2
+
+    return err, exit_code
+
+  def clearIPv4Table(self):
+    self.clearTable(iptc.Table(iptc.Table.FILTER))
+
+  def clearIPv6Table(self):
+    self.clearTable(iptc.Table6(iptc.Table6.FILTER))
+
+  def clearTable(self, filter_table):
+    filter_table.autocommit = False
+    forward_chain = iptc.Chain(filter_table, "FORWARD")
+    input_chain = iptc.Chain(filter_table, "INPUT")
+    mailcow_chain = iptc.Chain(filter_table, self.chain_name)
+    if mailcow_chain in filter_table.chains:
+      for rule in mailcow_chain.rules:
+        mailcow_chain.delete_rule(rule)
+      for rule in forward_chain.rules:
+        if rule.target.name == self.chain_name:
+          forward_chain.delete_rule(rule)
+      for rule in input_chain.rules:
+        if rule.target.name == self.chain_name:
+          input_chain.delete_rule(rule)
+      filter_table.delete_chain(self.chain_name)
+    filter_table.commit()
+    filter_table.refresh()
+    filter_table.autocommit = True
+
+  def banIPv4(self, source):
+    chain = iptc.Chain(iptc.Table(iptc.Table.FILTER), self.chain_name)
+    rule = iptc.Rule()
+    rule.src = source
+    target = iptc.Target(rule, "REJECT")
+    rule.target = target
+    if rule in chain.rules:
+      return False
+    chain.insert_rule(rule)
+    return True
+
+  def banIPv6(self, source):
+    chain = iptc.Chain(iptc.Table6(iptc.Table6.FILTER), self.chain_name)
+    rule = iptc.Rule6()
+    rule.src = source
+    target = iptc.Target(rule, "REJECT")
+    rule.target = target
+    if rule in chain.rules:
+      return False
+    chain.insert_rule(rule)
+    return True
+
+  def unbanIPv4(self, source):
+    chain = iptc.Chain(iptc.Table(iptc.Table.FILTER), self.chain_name)
+    rule = iptc.Rule()
+    rule.src = source
+    target = iptc.Target(rule, "REJECT")
+    rule.target = target
+    if rule not in chain.rules: 
+      return False
+    chain.delete_rule(rule)
+    return True
+
+  def unbanIPv6(self, source):
+    chain = iptc.Chain(iptc.Table6(iptc.Table6.FILTER), self.chain_name)
+    rule = iptc.Rule6()
+    rule.src = source
+    target = iptc.Target(rule, "REJECT")
+    rule.target = target
+    if rule not in chain.rules:
+      return False
+    chain.delete_rule(rule)
+    return True
+
+  def snat4(self, snat_target, source):
+    try:
+      table = iptc.Table('nat')
+      table.refresh()
+      chain = iptc.Chain(table, 'POSTROUTING')
+      table.autocommit = False
+      new_rule = self.getSnat4Rule(snat_target, source)
+
+      if not chain.rules:
+        # if there are no rules in the chain, insert the new rule directly
+        self.logger.logInfo(f'Added POSTROUTING rule for source network {new_rule.src} to SNAT target {snat_target}')
+        chain.insert_rule(new_rule)
+      else:
+        for position, rule in enumerate(chain.rules):
+          if not hasattr(rule.target, 'parameter'):
+              continue
+          match = all((
+            new_rule.get_src() == rule.get_src(),
+            new_rule.get_dst() == rule.get_dst(),
+            new_rule.target.parameters == rule.target.parameters,
+            new_rule.target.name == rule.target.name
+          ))
+          if position == 0:
+            if not match:
+              self.logger.logInfo(f'Added POSTROUTING rule for source network {new_rule.src} to SNAT target {snat_target}')
+              chain.insert_rule(new_rule)
+          else:
+            if match:
+              self.logger.logInfo(f'Remove rule for source network {new_rule.src} to SNAT target {snat_target} from POSTROUTING chain at position {position}')
+              chain.delete_rule(rule)
+
+      table.commit()
+      table.autocommit = True
+      return True
+    except:
+      self.logger.logCrit('Error running SNAT4, retrying...')
+      return False
+
+  def snat6(self, snat_target, source):
+    try:
+      table = iptc.Table6('nat')
+      table.refresh()
+      chain = iptc.Chain(table, 'POSTROUTING')
+      table.autocommit = False
+      new_rule = self.getSnat6Rule(snat_target, source)
+
+      if new_rule not in chain.rules:
+        self.logger.logInfo('Added POSTROUTING rule for source network %s to SNAT target %s' % (new_rule.src, snat_target))
+        chain.insert_rule(new_rule)
+      else:
+        for position, item in enumerate(chain.rules):
+          if item == new_rule:
+            if position != 0:
+              chain.delete_rule(new_rule)
+    
+      table.commit()
+      table.autocommit = True
+    except:
+      self.logger.logCrit('Error running SNAT6, retrying...')
+
+
+  def getSnat4Rule(self, snat_target, source):
+    rule = iptc.Rule()
+    rule.src = source
+    rule.dst = '!' + rule.src
+    target = rule.create_target("SNAT")
+    target.to_source = snat_target
+    match = rule.create_match("comment")
+    match.comment = f'{int(round(time.time()))}'
+    return rule
+
+  def getSnat6Rule(self, snat_target, source):
+    rule = iptc.Rule6()
+    rule.src = source
+    rule.dst = '!' + rule.src
+    target = rule.create_target("SNAT")
+    target.to_source = snat_target
+    return rule
+
+  def create_mailcow_isolation_rule(self, _interface:str, _dports:list, _allow:str = ""):
+    try:
+      chain = iptc.Chain(iptc.Table(iptc.Table.FILTER), self.chain_name)
+
+      # insert mailcow isolation rule
+      rule = iptc.Rule()
+      rule.in_interface = f'!{_interface}'
+      rule.out_interface = _interface
+      rule.protocol = 'tcp'
+      rule.create_target("DROP")
+      match = rule.create_match("multiport")
+      match.dports = ','.join(map(str, _dports))
+
+      if rule in chain.rules:
+        chain.delete_rule(rule)
+      chain.insert_rule(rule, position=0)
+
+      # insert mailcow isolation exception rule
+      if _allow != "":
+        rule = iptc.Rule()
+        rule.src = _allow
+        rule.in_interface = f'!{_interface}'
+        rule.out_interface = _interface
+        rule.protocol = 'tcp'
+        rule.create_target("ACCEPT")
+        match = rule.create_match("multiport")
+        match.dports = ','.join(map(str, _dports))
+
+        if rule in chain.rules:
+          chain.delete_rule(rule)
+        chain.insert_rule(rule, position=0)
+
+
+      return True
+    except Exception as e:
+      self.logger.logCrit(f"Error adding {self.chain_name} isolation: {e}")
+      return False

data/Dockerfiles/netfilter/modules/Logger.py

@@ -0,0 +1,30 @@
+import time
+import json
+
+class Logger:
+  def __init__(self):
+    self.r = None
+
+  def set_redis(self, redis):
+    self.r = redis
+
+  def log(self, priority, message):
+    tolog = {}
+    tolog['time'] = int(round(time.time()))
+    tolog['priority'] = priority
+    tolog['message'] = message
+    print(message)
+    if self.r is not None:
+      try:
+        self.r.lpush('NETFILTER_LOG', json.dumps(tolog, ensure_ascii=False))
+      except Exception as ex:
+        print('Failed logging to redis: %s'  % (ex))
+
+  def logWarn(self, message):
+    self.log('warn', message)
+
+  def logCrit(self, message):
+    self.log('crit', message)
+
+  def logInfo(self, message):
+    self.log('info', message)

data/Dockerfiles/netfilter/modules/NFTables.py

@@ -0,0 +1,659 @@
+import nftables
+import ipaddress
+import os
+
+class NFTables:
+  def __init__(self, chain_name, logger):
+    self.chain_name = chain_name
+    self.logger = logger
+
+    self.nft = nftables.Nftables()
+    self.nft.set_json_output(True)
+    self.nft.set_handle_output(True)
+    self.nft_chain_names = {'ip': {'filter': {'input': '', 'forward': ''}, 'nat': {'postrouting': ''} },
+                            'ip6': {'filter': {'input': '', 'forward': ''}, 'nat': {'postrouting': ''} } }
+
+    self.search_current_chains()
+
+  def initChainIPv4(self):
+    self.insert_mailcow_chains("ip")
+
+  def initChainIPv6(self):
+    self.insert_mailcow_chains("ip6")
+
+  def checkIPv4ChainOrder(self):
+    return self.checkChainOrder("ip")
+
+  def checkIPv6ChainOrder(self):
+    return self.checkChainOrder("ip6")
+
+  def checkChainOrder(self, filter_table):
+    err = False
+    exit_code = None
+
+    for chain in ['input', 'forward']:
+      chain_position = self.check_mailcow_chains(filter_table, chain)
+      if chain_position is None: continue
+
+      if chain_position is False:
+        self.logger.logCrit(f'MAILCOW target not found in {filter_table} {chain} table, restarting container to fix it...')
+        err = True
+        exit_code = 2
+
+      if chain_position > 0:
+        chain_position += 1
+        self.logger.logCrit(f'MAILCOW target is in position {chain_position} in the {filter_table} {chain} table, restarting container to fix it...')
+        err = True
+        exit_code = 2
+
+    return err, exit_code
+
+  def clearIPv4Table(self):
+    self.clearTable("ip")
+
+  def clearIPv6Table(self):
+    self.clearTable("ip6")
+
+  def clearTable(self, _family):
+    is_empty_dict = True
+    json_command = self.get_base_dict()
+    chain_handle = self.get_chain_handle(_family, "filter", self.chain_name)
+    # if no handle, the chain doesn't exists
+    if chain_handle is not None:
+      is_empty_dict = False
+      # flush chain
+      mailcow_chain = {'family': _family, 'table': 'filter', 'name': self.chain_name}
+      flush_chain = {'flush': {'chain': mailcow_chain}}
+      json_command["nftables"].append(flush_chain)
+
+    # remove rule in forward chain
+    # remove rule in input chain
+    chains_family = [self.nft_chain_names[_family]['filter']['input'],
+                    self.nft_chain_names[_family]['filter']['forward'] ]
+
+    for chain_base in chains_family:
+      if not chain_base: continue
+
+      rules_handle = self.get_rules_handle(_family, "filter", chain_base)
+      if rules_handle is not None:
+        for r_handle in rules_handle:
+          is_empty_dict = False
+          mailcow_rule = {'family':_family,
+                          'table': 'filter',
+                          'chain': chain_base,
+                          'handle': r_handle }
+          delete_rules = {'delete': {'rule': mailcow_rule} }
+          json_command["nftables"].append(delete_rules)
+
+    # remove chain
+    # after delete all rules referencing this chain
+    if chain_handle is not None:
+      mc_chain_handle = {'family':_family,
+                        'table': 'filter',
+                        'name': self.chain_name,
+                        'handle': chain_handle }
+      delete_chain = {'delete': {'chain': mc_chain_handle} }
+      json_command["nftables"].append(delete_chain)
+
+    if is_empty_dict == False:
+      if self.nft_exec_dict(json_command):
+        self.logger.logInfo(f"Clear completed: {_family}")
+
+  def banIPv4(self, source):
+    ban_dict = self.get_ban_ip_dict(source, "ip")
+    return self.nft_exec_dict(ban_dict)
+
+  def banIPv6(self, source):
+    ban_dict = self.get_ban_ip_dict(source, "ip6")
+    return self.nft_exec_dict(ban_dict)
+
+  def unbanIPv4(self, source):
+    unban_dict = self.get_unban_ip_dict(source, "ip")
+    if not unban_dict:
+      return False
+    return self.nft_exec_dict(unban_dict)
+
+  def unbanIPv6(self, source):
+    unban_dict = self.get_unban_ip_dict(source, "ip6")
+    if not unban_dict:
+      return False
+    return self.nft_exec_dict(unban_dict)
+
+  def snat4(self, snat_target, source):
+    self.snat_rule("ip", snat_target, source)
+
+  def snat6(self, snat_target, source):
+    self.snat_rule("ip6", snat_target, source)
+
+
+  def nft_exec_dict(self, query: dict):
+    if not query: return False
+
+    rc, output, error = self.nft.json_cmd(query)
+    if rc != 0:
+      #self.logger.logCrit(f"Nftables Error: {error}")
+      return False
+
+    # Prevent returning False or empty string on commands that do not produce output
+    if rc == 0 and len(output) == 0:
+      return True
+
+    return output
+
+  def get_base_dict(self):
+    return {'nftables': [{ 'metainfo': { 'json_schema_version': 1} } ] }
+
+  def search_current_chains(self):
+    nft_chain_priority = {'ip': {'filter': {'input': None, 'forward': None}, 'nat': {'postrouting': None} },
+                      'ip6': {'filter': {'input': None, 'forward': None}, 'nat': {'postrouting': None} } }
+
+    # Command: 'nft list chains'
+    _list = {'list' : {'chains': 'null'} }
+    command = self.get_base_dict()
+    command['nftables'].append(_list)
+    kernel_ruleset = self.nft_exec_dict(command)
+    if kernel_ruleset:
+      for _object in kernel_ruleset['nftables']:
+        chain = _object.get("chain")
+        if not chain: continue
+
+        _family = chain['family']
+        _table = chain['table']
+        _hook = chain.get("hook")
+        _priority = chain.get("prio")
+        _name = chain['name']
+
+        if _family not in self.nft_chain_names: continue
+        if _table not in self.nft_chain_names[_family]: continue
+        if _hook not in self.nft_chain_names[_family][_table]: continue
+        if _priority is None: continue
+
+        _saved_priority = nft_chain_priority[_family][_table][_hook]
+        if _saved_priority is None or _priority < _saved_priority:
+          # at this point, we know the chain has:
+          # hook and priority set
+          # and it has the lowest priority
+          nft_chain_priority[_family][_table][_hook] = _priority
+          self.nft_chain_names[_family][_table][_hook] = _name
+
+  def search_for_chain(self, kernel_ruleset: dict, chain_name: str):
+    found = False
+    for _object in kernel_ruleset["nftables"]:
+      chain = _object.get("chain")
+      if not chain:
+        continue
+      ch_name = chain.get("name")
+      if ch_name == chain_name:
+        found = True
+        break
+    return found
+
+  def get_chain_dict(self, _family: str, _name: str):
+    # nft (add | create) chain [<family>] <table> <name> 
+    _chain_opts = {'family': _family, 'table': 'filter', 'name': _name  }
+    _add = {'add': {'chain': _chain_opts} }
+    final_chain = self.get_base_dict()
+    final_chain["nftables"].append(_add)
+    return final_chain
+
+  def get_mailcow_jump_rule_dict(self, _family: str, _chain: str):
+    _jump_rule = self.get_base_dict()
+    _expr_opt=[]
+    _expr_counter = {'family': _family, 'table': 'filter', 'packets': 0, 'bytes': 0}
+    _counter_dict = {'counter': _expr_counter}
+    _expr_opt.append(_counter_dict)
+
+    _jump_opts = {'jump': {'target': self.chain_name} }
+
+    _expr_opt.append(_jump_opts)
+
+    _rule_params = {'family': _family,
+                    'table': 'filter',
+                    'chain': _chain,
+                    'expr': _expr_opt,
+                    'comment': "mailcow" }
+
+    _add_rule = {'insert': {'rule': _rule_params} }
+
+    _jump_rule["nftables"].append(_add_rule)
+
+    return _jump_rule
+
+  def insert_mailcow_chains(self, _family: str):
+    nft_input_chain = self.nft_chain_names[_family]['filter']['input']
+    nft_forward_chain = self.nft_chain_names[_family]['filter']['forward']
+    # Command: 'nft list table <family> filter'
+    _table_opts = {'family': _family, 'name': 'filter'}
+    _list = {'list': {'table': _table_opts} }
+    command = self.get_base_dict()
+    command['nftables'].append(_list)
+    kernel_ruleset = self.nft_exec_dict(command)
+    if kernel_ruleset:
+      # chain
+      if not self.search_for_chain(kernel_ruleset, self.chain_name):
+        cadena = self.get_chain_dict(_family, self.chain_name)
+        if self.nft_exec_dict(cadena):
+          self.logger.logInfo(f"MAILCOW {_family} chain created successfully.")
+
+      input_jump_found, forward_jump_found = False, False
+
+      for _object in kernel_ruleset["nftables"]:
+        if not _object.get("rule"):
+          continue
+
+        rule = _object["rule"]
+        if nft_input_chain and rule["chain"] == nft_input_chain:
+          if rule.get("comment") and rule["comment"] == "mailcow":
+            input_jump_found = True
+        if nft_forward_chain and rule["chain"] == nft_forward_chain:
+          if rule.get("comment") and rule["comment"] == "mailcow":
+            forward_jump_found = True
+
+      if not input_jump_found:
+        command = self.get_mailcow_jump_rule_dict(_family, nft_input_chain)
+        self.nft_exec_dict(command)
+
+      if not forward_jump_found:
+        command = self.get_mailcow_jump_rule_dict(_family, nft_forward_chain)
+        self.nft_exec_dict(command)
+
+  def delete_nat_rule(self, _family:str, _chain: str, _handle:str):
+    delete_command = self.get_base_dict()
+    _rule_opts = {'family': _family,
+                  'table': 'nat',
+                  'chain': _chain,
+                  'handle': _handle  }
+    _delete = {'delete': {'rule': _rule_opts} }
+    delete_command["nftables"].append(_delete)
+
+    return self.nft_exec_dict(delete_command)
+
+  def delete_filter_rule(self, _family:str, _chain: str, _handle:str):
+    delete_command = self.get_base_dict()
+    _rule_opts = {'family': _family,
+                  'table': 'filter',
+                  'chain': _chain,
+                  'handle': _handle  }
+    _delete = {'delete': {'rule': _rule_opts} }
+    delete_command["nftables"].append(_delete)
+
+    return self.nft_exec_dict(delete_command)
+
+  def snat_rule(self, _family: str, snat_target: str, source_address: str):
+    chain_name = self.nft_chain_names[_family]['nat']['postrouting']
+
+    # no postrouting chain, may occur if docker has ipv6 disabled.
+    if not chain_name: return
+
+    # Command: nft list chain <family> nat <chain_name>
+    _chain_opts = {'family': _family, 'table': 'nat', 'name': chain_name}
+    _list = {'list':{'chain': _chain_opts} }
+    command = self.get_base_dict()
+    command['nftables'].append(_list)
+    kernel_ruleset = self.nft_exec_dict(command)
+    if not kernel_ruleset:
+      return
+
+    rule_position = 0
+    rule_handle = None
+    rule_found = False
+    for _object in kernel_ruleset["nftables"]:
+      if not _object.get("rule"):
+        continue
+
+      rule = _object["rule"]
+      if not rule.get("comment") or not rule["comment"] == "mailcow":
+        rule_position +=1
+        continue
+
+      rule_found = True
+      rule_handle = rule["handle"]
+      break
+
+    dest_net = ipaddress.ip_network(source_address, strict=False)
+    target_net = ipaddress.ip_network(snat_target, strict=False)
+
+    if rule_found:
+      saddr_ip = rule["expr"][0]["match"]["right"]["prefix"]["addr"]
+      saddr_len = int(rule["expr"][0]["match"]["right"]["prefix"]["len"])
+
+      daddr_ip = rule["expr"][1]["match"]["right"]["prefix"]["addr"]
+      daddr_len = int(rule["expr"][1]["match"]["right"]["prefix"]["len"])
+
+      target_ip = rule["expr"][3]["snat"]["addr"]
+
+      saddr_net = ipaddress.ip_network(saddr_ip + '/' + str(saddr_len), strict=False)
+      daddr_net = ipaddress.ip_network(daddr_ip + '/' + str(daddr_len), strict=False)
+      current_target_net = ipaddress.ip_network(target_ip, strict=False)
+
+      match = all((
+                dest_net == saddr_net,
+                dest_net == daddr_net,
+                target_net == current_target_net
+              ))
+      try:
+        if rule_position == 0:
+          if not match:
+            # Position 0 , it is a mailcow rule , but it does not have the same parameters
+            if self.delete_nat_rule(_family, chain_name, rule_handle):
+              self.logger.logInfo(f'Remove rule for source network {saddr_net} to SNAT target {target_net} from {_family} nat {chain_name} chain, rule does not match configured parameters')
+        else:
+          # Position > 0 and is mailcow rule
+          if self.delete_nat_rule(_family, chain_name, rule_handle):
+            self.logger.logInfo(f'Remove rule for source network {saddr_net} to SNAT target {target_net} from {_family} nat {chain_name} chain, rule is at position {rule_position}')
+      except:
+          self.logger.logCrit(f"Error running SNAT on {_family}, retrying..." )
+    else:
+      # rule not found
+      json_command = self.get_base_dict()
+      try:
+        snat_dict = {'snat': {'addr': str(target_net.network_address)} }
+
+        expr_counter = {'family': _family, 'table': 'nat', 'packets': 0, 'bytes': 0}
+        counter_dict = {'counter': expr_counter}
+
+        prefix_dict = {'prefix': {'addr': str(dest_net.network_address), 'len': int(dest_net.prefixlen)} }
+        payload_dict = {'payload': {'protocol': _family, 'field': "saddr"} }
+        match_dict1 = {'match': {'op': '==', 'left': payload_dict, 'right': prefix_dict} }
+
+        payload_dict2 = {'payload': {'protocol': _family, 'field': "daddr"} }
+        match_dict2 = {'match': {'op': '!=', 'left': payload_dict2, 'right': prefix_dict } }
+        expr_list = [
+                    match_dict1,
+                    match_dict2,
+                    counter_dict,
+                    snat_dict
+                    ]
+        rule_fields = {'family': _family,
+                        'table': 'nat',
+                        'chain': chain_name,
+                        'comment': "mailcow",
+                        'expr': expr_list }
+
+        insert_dict = {'insert': {'rule': rule_fields} }
+        json_command["nftables"].append(insert_dict)
+        if self.nft_exec_dict(json_command):
+          self.logger.logInfo(f'Added {_family} nat {chain_name} rule for source network {dest_net} to {target_net}')
+      except:
+        self.logger.logCrit(f"Error running SNAT on {_family}, retrying...")
+
+  def get_chain_handle(self, _family: str, _table: str, chain_name: str):
+    chain_handle = None
+    # Command: 'nft list chains {family}'
+    _list = {'list': {'chains': {'family': _family} } }
+    command = self.get_base_dict()
+    command['nftables'].append(_list)
+    kernel_ruleset = self.nft_exec_dict(command)
+    if kernel_ruleset:
+      for _object in kernel_ruleset["nftables"]:
+        if not _object.get("chain"):
+          continue
+        chain = _object["chain"]
+        if chain["family"] == _family and chain["table"] == _table and chain["name"] == chain_name:
+          chain_handle = chain["handle"]
+          break
+    return chain_handle
+
+  def get_rules_handle(self, _family: str, _table: str, chain_name: str, _comment_filter = "mailcow"):
+    rule_handle = []
+    # Command: 'nft list chain {family} {table} {chain_name}'
+    _chain_opts = {'family': _family, 'table': _table, 'name': chain_name}
+    _list = {'list': {'chain': _chain_opts} }
+    command = self.get_base_dict()
+    command['nftables'].append(_list)
+
+    kernel_ruleset = self.nft_exec_dict(command)
+    if kernel_ruleset:
+      for _object in kernel_ruleset["nftables"]:
+        if not _object.get("rule"):
+          continue
+
+        rule = _object["rule"]
+        if rule["family"] == _family and rule["table"] == _table and rule["chain"] == chain_name:
+          if rule.get("comment") and rule["comment"] == _comment_filter:
+            rule_handle.append(rule["handle"])
+    return rule_handle
+
+  def get_ban_ip_dict(self, ipaddr: str, _family: str):
+    json_command = self.get_base_dict()
+
+    expr_opt = []
+    ipaddr_net = ipaddress.ip_network(ipaddr, strict=False)
+    right_dict = {'prefix': {'addr': str(ipaddr_net.network_address), 'len': int(ipaddr_net.prefixlen) } }
+
+    left_dict = {'payload': {'protocol': _family, 'field': 'saddr'} }
+    match_dict = {'op': '==', 'left': left_dict, 'right': right_dict }
+    expr_opt.append({'match': match_dict})
+
+    counter_dict = {'counter': {'family': _family, 'table': "filter", 'packets': 0, 'bytes': 0} }
+    expr_opt.append(counter_dict)
+
+    expr_opt.append({'drop': "null"})
+
+    rule_dict = {'family': _family, 'table': "filter", 'chain': self.chain_name, 'expr': expr_opt}
+
+    base_dict = {'insert': {'rule': rule_dict} }
+    json_command["nftables"].append(base_dict)
+
+    return json_command
+
+  def get_unban_ip_dict(self, ipaddr:str, _family: str):
+    json_command = self.get_base_dict()
+    # Command: 'nft list chain {s_family} filter  MAILCOW'
+    _chain_opts = {'family': _family, 'table': 'filter', 'name': self.chain_name}
+    _list = {'list': {'chain': _chain_opts} }
+    command = self.get_base_dict()
+    command['nftables'].append(_list)
+    kernel_ruleset = self.nft_exec_dict(command)
+    rule_handle = None
+    if kernel_ruleset:
+      for _object in kernel_ruleset["nftables"]:
+        if not _object.get("rule"):
+          continue
+
+        rule = _object["rule"]["expr"][0]["match"]
+        if not "payload" in rule["left"]:
+          continue
+        left_opt = rule["left"]["payload"]
+        if not left_opt["protocol"] == _family:
+          continue
+        if not left_opt["field"] =="saddr":
+          continue
+
+        # ip currently banned
+        rule_right = rule["right"]
+        if isinstance(rule_right, dict):
+          current_rule_ip = rule_right["prefix"]["addr"] + '/' + str(rule_right["prefix"]["len"])
+        else:
+          current_rule_ip = rule_right
+        current_rule_net = ipaddress.ip_network(current_rule_ip)
+
+        # ip to ban
+        candidate_net = ipaddress.ip_network(ipaddr, strict=False)
+
+        if current_rule_net == candidate_net:
+          rule_handle = _object["rule"]["handle"]
+          break
+
+      if rule_handle is not None:
+        mailcow_rule = {'family': _family, 'table': 'filter', 'chain': self.chain_name, 'handle': rule_handle}
+        delete_rule = {'delete': {'rule': mailcow_rule} }
+        json_command["nftables"].append(delete_rule)
+      else:
+        return False
+
+    return json_command
+
+  def check_mailcow_chains(self, family: str, chain: str):
+    position = 0
+    rule_found = False
+    chain_name = self.nft_chain_names[family]['filter'][chain]
+
+    if not chain_name: return None
+
+    _chain_opts = {'family': family, 'table': 'filter', 'name': chain_name}
+    _list = {'list': {'chain': _chain_opts}}
+    command = self.get_base_dict()
+    command['nftables'].append(_list)
+    kernel_ruleset = self.nft_exec_dict(command)
+    if kernel_ruleset:
+      for _object in kernel_ruleset["nftables"]:
+        if not _object.get("rule"):
+          continue
+        rule = _object["rule"]
+        if rule.get("comment") and rule["comment"] == "mailcow":
+          rule_found = True
+          break
+
+        position+=1
+
+    return position if rule_found else False
+
+  def create_mailcow_isolation_rule(self, _interface:str, _dports:list, _allow:str = ""):
+    family = "ip"
+    table = "filter"
+    comment_filter_drop = "mailcow isolation"
+    comment_filter_allow = "mailcow isolation allow"
+    json_command = self.get_base_dict()
+
+    # Delete old mailcow isolation rules
+    handles = self.get_rules_handle(family, table, self.chain_name, comment_filter_drop)
+    for handle in handles:
+      self.delete_filter_rule(family, self.chain_name, handle)
+    handles = self.get_rules_handle(family, table, self.chain_name, comment_filter_allow)
+    for handle in handles:
+      self.delete_filter_rule(family, self.chain_name, handle)
+
+    # insert mailcow isolation rule
+    _match_dict_drop = [
+      {
+        "match": {
+          "op": "!=",
+          "left": {
+            "meta": {
+              "key": "iifname"
+            }
+          },
+          "right": _interface
+        }
+      },
+      {
+        "match": {
+          "op": "==",
+          "left": {
+            "meta": {
+              "key": "oifname"
+            }
+          },
+          "right": _interface
+        }
+      },
+      {
+        "match": {
+          "op": "==",
+          "left": {
+            "payload": {
+              "protocol": "tcp",
+              "field": "dport"
+            }
+          },
+          "right": {
+            "set": _dports
+          }
+        }
+      },
+      {
+        "counter": {
+          "packets": 0,
+          "bytes": 0
+        }
+      },
+      {
+        "drop": None
+      }
+    ]
+    rule_drop = { "insert": { "rule": {
+      "family": family,
+      "table": table,
+      "chain": self.chain_name,
+      "comment": comment_filter_drop,
+      "expr": _match_dict_drop
+    }}}
+    json_command["nftables"].append(rule_drop)
+
+    # insert mailcow isolation allow rule
+    if _allow != "":
+      _match_dict_allow = [
+        {
+          "match": {
+            "op": "==",
+            "left": {
+              "payload": {
+                "protocol": "ip",
+                "field": "saddr"
+              }
+            },
+            "right": _allow
+          }
+        },
+        {
+          "match": {
+            "op": "!=",
+            "left": {
+              "meta": {
+                "key": "iifname"
+              }
+            },
+            "right": _interface
+          }
+        },
+        {
+          "match": {
+            "op": "==",
+            "left": {
+              "meta": {
+                "key": "oifname"
+              }
+            },
+            "right": _interface
+          }
+        },
+        {
+          "match": {
+            "op": "==",
+            "left": {
+              "payload": {
+                "protocol": "tcp",
+                "field": "dport"
+              }
+            },
+            "right": {
+              "set": _dports
+            }
+          }
+        },
+        {
+          "counter": {
+            "packets": 0,
+            "bytes": 0
+          }
+        },
+        {
+          "accept": None
+        }
+      ]
+      rule_allow = { "insert": { "rule": {
+        "family": family,
+        "table": table,
+        "chain": self.chain_name,
+        "comment": comment_filter_allow,
+        "expr": _match_dict_allow
+      }}}
+      json_command["nftables"].append(rule_allow)
+
+    success = self.nft_exec_dict(json_command)
+    if success == False:
+      self.logger.logCrit(f"Error adding {self.chain_name} isolation")
+      return False
+
+    return True