Role ipt-server: sync with ipt-server repo (93d9af8); adapt extract-fw-host-vars.py.

- Update firewall scripts and shared conf files from firewall/ipt-server
  (HTTP connection limits, IPv6 TCP MSS clamping, ban_ipv6_mask,
  mattermost TCP fallback, rename 'stansard_*' -> 'standard_*').
- New role variables: fw_set_max_new_http_conn_per_ip_per_second,
  fw_max_http_new_conn_per_ip_per_second, fw_set_max_concurrent_http_conn_per_ip,
  fw_max_concurrent_http_conn_per_ip, fw_set_max_new_http_conn_per_second,
  fw_max_new_http_conn_per_second, fw_throttle_tcp6_mss_for_https,
  fw_tcp6_mss_for_https_val, fw_mm_tcp_ports_in, fw_ban_ipv6_mask.
- Split fw_blocked_ips into fw_blocked_ips_v4 / fw_blocked_ips_v6 and
  rename it in host_vars accordingly.
- Restart firewall when scripts or shared conf files change.
- extract-fw-host-vars.py: map new variables, normalize '${var}' and renamed
  bash variables, fall back to IPv6 for shared variables and warn if IPv4
  and IPv6 values differ.
- README.md / MIGRATION.md: document host_vars naming
  (<short-hostname>-ipt-server.yml) and new variables.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

extract-fw-host-vars.py

@@ -21,7 +21,7 @@ from pathlib import Path
 
 
 # ---------------------------------------------------------------------------
-# Defaults matching roles/ipt-firewall/defaults/main.yml
+# Defaults matching roles/ipt-server/defaults/main.yml
 # Only values that differ from these will be emitted.
 # ---------------------------------------------------------------------------
 DEFAULTS = {
@@ -73,8 +73,19 @@ DEFAULTS = {
     "fw_http_ports": "$standard_http_ports",
     "fw_log_cgi_traffic_out": False,
     "fw_cgi_script_users": "",
+    "fw_set_max_new_http_conn_per_ip_per_second": True,
+    "fw_max_http_new_conn_per_ip_per_second": "$default_max_http_new_conn_per_ip_per_second",
+    "fw_set_max_concurrent_http_conn_per_ip": True,
+    "fw_max_concurrent_http_conn_per_ip": "$default_max_concurrent_http_conn_per_ip",
+    "fw_set_max_new_http_conn_per_second": True,
+    "fw_max_new_http_conn_per_second": "$default_max_new_http_conn_per_second",
+    "fw_throttle_tcp6_mss_for_https": False,
+    "fw_tcp6_mss_for_https_val": "$min_tcp6_mss_for_https_val",
     "fw_mm_server_ips": "",
     "fw_forward_mm_server_ips": "",
+    "fw_mm_udp_ports_in": "$standard_mattermost_udp_ports_in",
+    "fw_mm_tcp_ports_in": "$standard_mattermost_tcp_ports_in",
+    "fw_mm_udp_ports_out": "$standard_mattermost_udp_ports_out",
     "fw_smtpd_ips": "",
     "fw_forward_smtpd_ips": "",
     "fw_smtpd_additional_listen_ports": "",
@@ -141,7 +152,9 @@ DEFAULTS = {
     "fw_portforward_udp_v4": "",
     "fw_portforward_tcp_v6": "",
     "fw_portforward_udp_v6": "",
-    "fw_blocked_ips": "",
+    "fw_blocked_ips_v4": "",
+    "fw_blocked_ips_v6": "",
+    "fw_ban_ipv6_mask": "$default_ban_ipv6_mask",
     "fw_block_tcp_ports": "111 113 135 137:139 445",
     "fw_block_udp_ports": "111 137:139",
     "fw_create_traffic_counter": True,
@@ -207,8 +220,17 @@ MAIN_SHARED = {
     "http_ports": "fw_http_ports",
     "log_cgi_traffic_out": "fw_log_cgi_traffic_out",
     "cgi_script_users": "fw_cgi_script_users",
+    "set_max_new_http_conn_per_ip_per_second": "fw_set_max_new_http_conn_per_ip_per_second",
+    "max_http_new_conn_per_ip_per_second": "fw_max_http_new_conn_per_ip_per_second",
+    "set_max_concurrent_http_conn_per_ip": "fw_set_max_concurrent_http_conn_per_ip",
+    "max_concurrent_http_conn_per_ip": "fw_max_concurrent_http_conn_per_ip",
+    "set_max_new_http_conn_per_second": "fw_set_max_new_http_conn_per_second",
+    "max_new_http_conn_per_second": "fw_max_new_http_conn_per_second",
     "mm_server_ips": "fw_mm_server_ips",
     "forward_mm_server_ips": "fw_forward_mm_server_ips",
+    "mm_udp_ports_in": "fw_mm_udp_ports_in",
+    "mm_tcp_ports_in": "fw_mm_tcp_ports_in",
+    "mm_udp_ports_out": "fw_mm_udp_ports_out",
     "smtpd_ips": "fw_smtpd_ips",
     "forward_smtpd_ips": "fw_forward_smtpd_ips",
     "smtpd_additional_listen_ports": "fw_smtpd_additional_listen_ports",
@@ -265,7 +287,6 @@ MAIN_SHARED = {
     "forward_tcp_out_ports": "fw_forward_tcp_out_ports",
     "udp_out_ports": "fw_udp_out_ports",
     "forward_udp_out_ports": "fw_forward_udp_out_ports",
-    "blocked_ips": "fw_blocked_ips",
     "block_tcp_ports": "fw_block_tcp_ports",
     "block_udp_ports": "fw_block_udp_ports",
     "create_traffic_counter": "fw_create_traffic_counter",
@@ -307,6 +328,7 @@ MAIN_V4_ONLY = {
     "kernel_log_martians": "fw_kernel_log_martians",
     "kernel_deactivate_source_route": "fw_kernel_deactivate_source_route",
     "kernel_dont_accept_redirects": "fw_kernel_dont_accept_redirects",
+    "blocked_ips": "fw_blocked_ips_v4",
 }
 
 # IPv6-only variables (from main_ipv6.conf)
@@ -325,6 +347,16 @@ MAIN_V6_ONLY = {
     "xmmp_remote_out_services": "fw_xmmp_remote_out_services_v6",
     "resolver_allowed_networks": "fw_resolver_allowed_networks_v6",
     "kernel_forward_between_interfaces": "fw_kernel_forward_between_interfaces",
+    "throttle_tcp6_mss_for_https": "fw_throttle_tcp6_mss_for_https",
+    "tcp6_mss_for_https_val": "fw_tcp6_mss_for_https_val",
+    "ban_ipv6_mask": "fw_ban_ipv6_mask",
+    "blocked_ips": "fw_blocked_ips_v6",
+}
+
+# Renamed bash variables: old name → new name (applied to $var references)
+RENAMED_BASH_VARS = {
+    "stansard_mattermost_udp_ports_in": "standard_mattermost_udp_ports_in",
+    "stansard_mattermost_udp_ports_out": "standard_mattermost_udp_ports_out",
 }
 
 
@@ -430,6 +462,14 @@ def ssh_cat(host, user, port, path, sudo_password=None):
         return None
 
 
+def normalize_value(value):
+    """Normalize bash variable references: ${var} → $var, renamed vars → new name."""
+    value = re.sub(r'\$\{([A-Za-z_][A-Za-z0-9_]*)\}', r'$\1', value)
+    for old, new in RENAMED_BASH_VARS.items():
+        value = re.sub(r'\$' + old + r'\b', '$' + new, value)
+    return value
+
+
 def coerce_bool(value):
     """Convert bash true/false string to Python bool, or return string."""
     if value.lower() in ("true", "yes", "1"):
@@ -456,9 +496,11 @@ def yaml_value(v):
 def build_host_vars(parsed_iface_v4, parsed_iface_v6, parsed_main_v4, parsed_main_v6):
     """
     Map parsed bash variables to Ansible fw_* variables.
-    Returns dict of {ansible_var: value} containing only non-default values.
+    Returns (dict of {ansible_var: value} containing only non-default values,
+             list of warnings).
     """
     result = {}
+    warnings = []
 
     # --- Interfaces: extract lists from numbered vars ---
     def extract_list(parsed, prefix, suffix="", count=3):
@@ -501,11 +543,17 @@ def build_host_vars(parsed_iface_v4, parsed_iface_v6, parsed_main_v4, parsed_mai
         if v and v != DEFAULTS.get(ansible_var, ""):
             result[ansible_var] = v
 
-    # --- Shared main variables (read from ipv4) ---
+    # --- Shared main variables (read from ipv4, fall back to ipv6) ---
     for bash_var, ansible_var in MAIN_SHARED.items():
-        raw = parsed_main_v4.get(bash_var)
+        raw_v4 = parsed_main_v4.get(bash_var)
+        raw_v6 = parsed_main_v6.get(bash_var)
+        if raw_v4 is not None and raw_v6 is not None \
+                and normalize_value(raw_v4) != normalize_value(raw_v6):
+            warnings.append(f"  # {ansible_var}: IPv4 '{raw_v4}' != IPv6 '{raw_v6}' — IPv4 value used")
+        raw = raw_v4 if raw_v4 is not None else raw_v6
         if raw is None:
             continue
+        raw = normalize_value(raw)
         v = coerce_bool(raw) if raw.lower() in ("true", "false") else raw
         default = DEFAULTS.get(ansible_var)
         if v != default:
@@ -516,6 +564,7 @@ def build_host_vars(parsed_iface_v4, parsed_iface_v6, parsed_main_v4, parsed_mai
         raw = parsed_main_v4.get(bash_var)
         if raw is None:
             continue
+        raw = normalize_value(raw)
         v = coerce_bool(raw) if raw.lower() in ("true", "false") else raw
         default = DEFAULTS.get(ansible_var)
         if v != default:
@@ -526,12 +575,13 @@ def build_host_vars(parsed_iface_v4, parsed_iface_v6, parsed_main_v4, parsed_mai
         raw = parsed_main_v6.get(bash_var)
         if raw is None:
             continue
+        raw = normalize_value(raw)
         v = coerce_bool(raw) if raw.lower() in ("true", "false") else raw
         default = DEFAULTS.get(ansible_var)
         if v != default:
             result[ansible_var] = v
 
-    return result
+    return result, warnings
 
 
 def render_yaml(hostname, host_vars, all_warnings):
@@ -540,7 +590,7 @@ def render_yaml(hostname, host_vars, all_warnings):
         "---",
         f"# ipt-firewall configuration for {hostname}",
         "# Generated by extract-fw-host-vars.py - review before committing!",
-        "# Place in: host_vars/<hostname>/ipt_firewall.yml",
+        "# Place in: host_vars/<hostname>/<short-hostname>-ipt-server.yml",
         "",
     ]
 
@@ -574,7 +624,11 @@ def render_yaml(hostname, host_vars, all_warnings):
                                   "fw_allow_local_service_v6", "fw_allow_local_service_from_networks_v6"]),
         ("SSH", ["fw_ssh_server_ips", "fw_forward_ssh_server_ips", "fw_ssh_ports"]),
         ("HTTP", ["fw_http_server_ips", "fw_forward_http_server_ips", "fw_http_ports",
-                  "fw_log_cgi_traffic_out", "fw_cgi_script_users"]),
+                  "fw_log_cgi_traffic_out", "fw_cgi_script_users",
+                  "fw_set_max_new_http_conn_per_ip_per_second", "fw_max_http_new_conn_per_ip_per_second",
+                  "fw_set_max_concurrent_http_conn_per_ip", "fw_max_concurrent_http_conn_per_ip",
+                  "fw_set_max_new_http_conn_per_second", "fw_max_new_http_conn_per_second",
+                  "fw_throttle_tcp6_mss_for_https", "fw_tcp6_mss_for_https_val"]),
         ("Mail", ["fw_smtpd_ips", "fw_forward_smtpd_ips", "fw_smtpd_additional_listen_ports",
                   "fw_smtpd_additional_outgoing_ports", "fw_mail_server_ips", "fw_forward_mail_server_ips",
                   "fw_mail_user_ports", "fw_mail_client_ips", "fw_forward_mail_client_ips",
@@ -601,7 +655,8 @@ def render_yaml(hostname, host_vars, all_warnings):
                    "fw_jibri_server_ips", "fw_forward_jibri_server_ips", "fw_jibri_remote_jitsi_server"]),
         ("TURN / STUN", ["fw_nc_turn_server_ips", "fw_forward_nc_turn_server_ips",
                           "fw_nc_turn_ports", "fw_nc_turn_udp_ports"]),
-        ("Mattermost", ["fw_mm_server_ips", "fw_forward_mm_server_ips"]),
+        ("Mattermost", ["fw_mm_server_ips", "fw_forward_mm_server_ips",
+                        "fw_mm_udp_ports_in", "fw_mm_tcp_ports_in", "fw_mm_udp_ports_out"]),
         ("Prometheus", ["fw_prometheus_local_server_ips", "fw_prometheus_local_client_ips",
                         "fw_prometheus_remote_server_ips"]),
         ("Xymon", ["fw_xymon_server_ips", "fw_local_xymon_client", "fw_xymon_port"]),
@@ -610,7 +665,7 @@ def render_yaml(hostname, host_vars, all_warnings):
                        "fw_udp_out_ports", "fw_forward_udp_out_ports"]),
         ("Portforwarding", ["fw_portforward_tcp_v4", "fw_portforward_udp_v4",
                              "fw_portforward_tcp_v6", "fw_portforward_udp_v6"]),
-        ("Block", ["fw_blocked_ips", "fw_block_tcp_ports", "fw_block_udp_ports"]),
+        ("Block", ["fw_blocked_ips_v4", "fw_blocked_ips_v6", "fw_ban_ipv6_mask", "fw_block_tcp_ports", "fw_block_udp_ports"]),
         ("Protection / limits", ["fw_protection_against_syn_flooding",
                                   "fw_protection_against_port_scanning",
                                   "fw_protection_against_ssh_brute_force_attacks",
@@ -712,10 +767,11 @@ def main():
         if warnings:
             all_warnings.extend([f"  # [{key}] {w}" for w in warnings])
 
-    host_vars = build_host_vars(
+    host_vars, map_warnings = build_host_vars(
         parsed["iface_v4"], parsed["iface_v6"],
         parsed["main_v4"],  parsed["main_v6"],
     )
+    all_warnings.extend(map_warnings)
 
     yaml_text = render_yaml(hostname, host_vars, all_warnings)
 

host_vars/a.ns.oopen.de/a.ns-ipt-server.yml

@@ -24,4 +24,4 @@ fw_dns_server_ips: $ext_ips
 fw_wireguard_server_ips: $ext_ips
 
 # --- Block
-fw_blocked_ips: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14
+fw_blocked_ips_v4: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14

host_vars/b.ns.oopen.de/b.ns-ipt-server.yml

@@ -24,4 +24,4 @@ fw_dns_server_ips: $ext_ips
 fw_wireguard_server_ips: $ext_ips
 
 # --- Block
-fw_blocked_ips: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14
+fw_blocked_ips_v4: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14

host_vars/backup.oopen.de/backup-ipt-server.yml

@@ -36,4 +36,4 @@ fw_http_server_ips: $ext_ips
 fw_tcp_out_ports: 51372 51374
 
 # --- Block
-fw_blocked_ips: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14
+fw_blocked_ips_v4: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14

host_vars/backup.warenform.de/backup-ipt-server.yml

@@ -21,4 +21,4 @@ munin_remote_ipv6: "2a01:4f9:3070:2bda::227"
 fw_http_server_ips: $ext_1_ip
 
 # --- Block
-fw_blocked_ips: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14
+fw_blocked_ips_v4: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14

host_vars/cl-01.oopen.de/cl-01-ipt-server.yml

@@ -24,4 +24,4 @@ fw_http_server_ips: $ext_1_ip
 fw_mail_client_ips: $ext_1_ip
 
 # --- Block
-fw_blocked_ips: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14
+fw_blocked_ips_v4: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14

host_vars/cl-02.oopen.de/cl-02-ipt-server.yml

@@ -24,4 +24,4 @@ fw_http_server_ips: $ext_1_ip
 fw_mail_client_ips: $ext_1_ip
 
 # --- Block
-fw_blocked_ips: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14
+fw_blocked_ips_v4: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14

host_vars/cl-fm.oopen.de/cl-fm-ipt-server.yml

@@ -24,4 +24,4 @@ fw_http_server_ips: $ext_1_ip
 fw_mail_client_ips: $ext_1_ip
 
 # --- Block
-fw_blocked_ips: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14
+fw_blocked_ips_v4: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14

host_vars/cl-lubax.oopen.de/cl-lubax-ipt-server.yml

@@ -24,4 +24,4 @@ fw_http_server_ips: $ext_1_ip
 fw_mail_client_ips: $ext_1_ip
 
 # --- Block
-# fw_blocked_ips: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14
+# fw_blocked_ips_v4: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14

host_vars/test.mx.oopen.de/test.mx-ipt-server.yml

@@ -36,4 +36,4 @@ fw_mumble_server_ips: 138.201.33.54
 fw_rsync_out_ips: $ext_1_ip
 
 # --- Block
-fw_blocked_ips: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14
+fw_blocked_ips_v4: 222.184.0.0/13 61.160.0.0/16 116.8.0.0/14

roles/ipt-server/MIGRATION.md

@@ -17,7 +17,7 @@ Das alte Verfahren:
 
 Das neue Verfahren:
 
-- Alle Firewall-Einstellungen liegen in `host_vars/${HOSTNAME}/ipt-server.yml`.
+- Alle Firewall-Einstellungen liegen in `host_vars/${HOSTNAME}/${HOSTNAME%.*.*}-ipt-server.yml`.
 - Ansible deployt die Config-Dateien aus Jinja2-Templates.
 - Direktes Editieren auf dem Host ist nicht mehr vorgesehen.
 
@@ -57,7 +57,7 @@ cd /path/to/ansible/oopen-server
 HOSTNAME=<hostname>
 
 ./extract-fw-host-vars.py ${HOSTNAME} --sudo \
-  -o host_vars/${HOSTNAME}/ipt-server.yml
+  -o host_vars/${HOSTNAME}/${HOSTNAME%.*.*}-ipt-server.yml
 ```
 
 Das Skript fragt einmalig nach dem `sudo`-Passwort.
@@ -65,7 +65,7 @@ Das Skript fragt einmalig nach dem `sudo`-Passwort.
 **Ergebnis prüfen:**
 
 ```bash
-cat host_vars/${HOSTNAME}/ipt-server.yml
+cat host_vars/${HOSTNAME}/${HOSTNAME%.*.*}-ipt-server.yml
 ```
 
 Kontrollpunkte:
@@ -114,7 +114,7 @@ Jetzt wird `fw_manage_config: true` gesetzt, damit Ansible die vier
 host-spezifischen Config-Dateien aus den Templates schreibt:
 
 ```yaml
-# host_vars/${HOSTNAME}/ipt-server.yml
+# host_vars/${HOSTNAME}/${HOSTNAME%.*.*}-ipt-server.yml
 ---
 fw_manage_config: true   # ← hinzufügen / auf true setzen
 
@@ -159,7 +159,7 @@ Config-Dateien produzieren exakt dieselben Rules wie die bisher händisch
 verwalteten.
 
 Falls Unterschiede erscheinen: die abweichenden Rules identifizieren, die
-entsprechenden Variablen in `host_vars/${HOSTNAME}/ipt-server.yml` nachpflegen,
+entsprechenden Variablen in `host_vars/${HOSTNAME}/${HOSTNAME%.*.*}-ipt-server.yml` nachpflegen,
 erneut ausrollen und den Diff wiederholen.
 
 Ab jetzt:
@@ -204,7 +204,7 @@ Hinweis (via `{{ ansible_managed }}`):
 ```ini
 # Ansible managed
 # DO NOT EDIT - changes will be overwritten on the next Ansible run.
-# Edit host_vars/${HOSTNAME}/ipt-server.yml instead.
+# Edit host_vars/${HOSTNAME}/${HOSTNAME%.*.*}-ipt-server.yml instead.
 ```
 
 ---

roles/ipt-server/README.md

@@ -42,9 +42,14 @@ roles/ipt-server/
 Host-spezifische Konfiguration liegt ausschließlich in:
 
 ```
-host_vars/${HOSTNAME}/ipt-server.yml
+host_vars/${HOSTNAME}/${HOSTNAME%.*.*}-ipt-server.yml
 ```
 
+Der Dateiname beginnt mit dem Hostnamen ohne Domain, z.B.
+`host_vars/a.mx.oopen.de/a.mx-ipt-server.yml` oder
+`host_vars/backup.oopen.de/backup-ipt-server.yml`
+(`${HOSTNAME%.*.*}` schneidet die letzten zwei Labels ab).
+
 ---
 
 ## Neuen Host aufnehmen
@@ -61,7 +66,7 @@ cd /path/to/ansible/oopen-server
 HOSTNAME=<hostname>
 
 mkdir -p host_vars/${HOSTNAME}
-cat > host_vars/${HOSTNAME}/ipt-server.yml << 'EOF'
+cat > host_vars/${HOSTNAME}/${HOSTNAME%.*.*}-ipt-server.yml << 'EOF'
 ---
 fw_manage_config: true
 
@@ -111,7 +116,7 @@ Was passiert:
 Alle Änderungen erfolgen ausschließlich in der host_vars-Datei des Hosts:
 
 ```
-host_vars/${HOSTNAME}/ipt-server.yml
+host_vars/${HOSTNAME}/${HOSTNAME%.*.*}-ipt-server.yml
 ```
 
 Danach:
@@ -132,7 +137,7 @@ tatsächlichen Änderungen wird die Firewall neu gestartet.
 ### Beispiel: HTTP-Server aktivieren
 
 ```yaml
-# host_vars/${HOSTNAME}/ipt-server.yml
+# host_vars/${HOSTNAME}/${HOSTNAME%.*.*}-ipt-server.yml
 fw_http_server_ips: "$ext_ips"   # oder konkrete IP
 ```
 
@@ -172,8 +177,17 @@ chmod 750 $DST/ipt-firewall-server $DST/ip6t-firewall-server
 
 Ebenso für geteilte Conf-Dateien in `roles/ipt-server/files/etc/ipt-firewall/`.
 
+Kommen dabei neue Variablen in `main_ipv4.conf.sample` / `main_ipv6.conf.sample`
+hinzu, müssen sie zusätzlich nachgezogen werden in:
+
+- `defaults/main.yml` (als `fw_*`-Variable mit Default),
+- `templates/etc/ipt-firewall/main_ipv{4,6}.conf.j2`,
+- `extract-fw-host-vars.py` (`DEFAULTS`, `MAIN_SHARED` bzw. `MAIN_V4_ONLY`/`MAIN_V6_ONLY`,
+  Sektion in `render_yaml`).
+
 Nach dem Commit werden die neuen Skripte beim nächsten Ansible-Run auf alle
-Hosts deployed.
+Hosts deployed. Geänderte Skripte oder geteilte Conf-Dateien lösen einen
+Neustart der Firewall aus.
 
 ---
 
@@ -188,6 +202,16 @@ Hosts deployed.
 | `fw_ssh_server_ips` | `"$ext_ips"` | IPs auf denen SSH erlaubt ist |
 | `fw_ssh_ports` | `"$standard_ssh_port"` | SSH-Port(s) |
 | `fw_http_server_ips` | `""` | IPs auf denen HTTP/HTTPS erlaubt ist |
+| `fw_set_max_new_http_conn_per_ip_per_second` | `true` | Neue HTTP(S)-Verbindungen/s pro Quell-IP begrenzen |
+| `fw_max_http_new_conn_per_ip_per_second` | `"$default_max_http_new_conn_per_ip_per_second"` | Limit dazu |
+| `fw_set_max_concurrent_http_conn_per_ip` | `true` | Gleichzeitige HTTP(S)-Verbindungen pro Quell-IP begrenzen |
+| `fw_max_concurrent_http_conn_per_ip` | `"$default_max_concurrent_http_conn_per_ip"` | Limit dazu |
+| `fw_set_max_new_http_conn_per_second` | `true` | SYN-Rate auf 80/443 insgesamt begrenzen |
+| `fw_max_new_http_conn_per_second` | `"$default_max_new_http_conn_per_second"` | Limit dazu |
+| `fw_throttle_tcp6_mss_for_https` | `false` | Nur IPv6: MSS eingehender HTTPS-SYNs clampen |
+| `fw_tcp6_mss_for_https_val` | `"$min_tcp6_mss_for_https_val"` | Nur IPv6: MSS-Wert (z.B. `1360`) |
+| `fw_mm_tcp_ports_in` | `"$standard_mattermost_tcp_ports_in"` | Mattermost TCP-Fallback (STUN) |
+| `fw_ban_ipv6_mask` | `"$default_ban_ipv6_mask"` | Nur IPv6: Präfixlänge für `ban_ipv6.list`-Einträge ohne Maske |
 | `munin_remote_ipv4` | `""` | Munin-Server IPv4 |
 | `munin_remote_ipv6` | `""` | Munin-Server IPv6 |
 

roles/ipt-server/defaults/main.yml

@@ -2,7 +2,7 @@
 
 # ---
 # ipt-firewall role defaults
-# Override per host in host_vars/<hostname>/ipt_firewall.yml
+# Override per host in host_vars/<hostname>/<short-hostname>-ipt-server.yml
 # ---
 
 
@@ -156,6 +156,19 @@ fw_http_ports: "$standard_http_ports"
 fw_log_cgi_traffic_out: false
 fw_cgi_script_users: ""
 
+# Restrictions on HTTP(S) connections (ports 80,443) to counteract attacks.
+# Values default to the 'default_*' settings in default_settings.conf.
+fw_set_max_new_http_conn_per_ip_per_second: true
+fw_max_http_new_conn_per_ip_per_second: "$default_max_http_new_conn_per_ip_per_second"
+fw_set_max_concurrent_http_conn_per_ip: true
+fw_max_concurrent_http_conn_per_ip: "$default_max_concurrent_http_conn_per_ip"
+fw_set_max_new_http_conn_per_second: true
+fw_max_new_http_conn_per_second: "$default_max_new_http_conn_per_second"
+
+# IPv6 only: clamp the advertised MSS of incoming HTTPS SYN packets.
+fw_throttle_tcp6_mss_for_https: false
+fw_tcp6_mss_for_https_val: "$min_tcp6_mss_for_https_val"
+
 
 # ---
 # Services: Mattermost
@@ -163,8 +176,9 @@ fw_cgi_script_users: ""
 
 fw_mm_server_ips: ""
 fw_forward_mm_server_ips: ""
-fw_mm_udp_ports_in: "$stansard_mattermost_udp_ports_in"
+fw_mm_udp_ports_in: "$standard_mattermost_udp_ports_in"
-fw_mm_udp_ports_out: "$stansard_mattermost_udp_ports_out"
+fw_mm_tcp_ports_in: "$standard_mattermost_tcp_ports_in"
+fw_mm_udp_ports_out: "$standard_mattermost_udp_ports_out"
 
 
 # ---
@@ -320,7 +334,9 @@ fw_portforward_udp_v6: ""
 # Blocked IPs / ports
 # ---
 
-fw_blocked_ips: ""
+fw_blocked_ips_v4: ""
+fw_blocked_ips_v6: ""
+fw_ban_ipv6_mask: "$default_ban_ipv6_mask"   # IPv6 only: prefix length for ban_ipv6.list entries without mask
 fw_block_tcp_ports: "111 113 135 137:139 445"
 fw_block_udp_ports: "111 137:139"
 

roles/ipt-server/files/etc/ipt-firewall/ban_ipv6.list.sample

@@ -10,8 +10,10 @@
 # -
 # -
 # - Note: 
-# -    - If no mask is given mask will be set to '64'
+# -    - If no mask is given mask will be set to 'ban_ipv6_mask' (main_ipv6.conf),
+# -      default is '128'
 # -    - wrong addresses like '2g01::1' or '2a01::1/129' will be ignored
+# -    - entries covering an own (global) address of this host will be ignored
 # -
 # - Example:
 # -    240e:ec:4ab1:feba:e8b4:4fb1:7984:4c

roles/ipt-server/files/etc/ipt-firewall/default_settings.conf

@@ -4,7 +4,7 @@
 # --- Default Parameter / Options
 # -------------
 
-default_per_IP_connection_limit=111
+default_per_IP_connection_limit=250
 
 
 # -------------
@@ -56,8 +56,9 @@ standard_prometheus_ports="9100,9256"
 
 # - Mattermost (MM) Service
 # -
-stansard_mattermost_udp_ports_in="8443"
+standard_mattermost_udp_ports_in="8443"
-stansard_mattermost_udp_ports_out="3478"
+standard_mattermost_tcp_ports_in="8443"
+standard_mattermost_udp_ports_out="3478"
 
 # - IPsec - Internet Security Association and
 # -  Key Management Protocol
@@ -70,6 +71,37 @@ standard_ipsec_nat_t=4500
 standard_http_ports="80,443"
 standard_mailuser_ports="587,465,110,995,143,993"
 
+
+# ip6t-firewall-server:
+#     Clamp the advertised MSS of incoming HTTPS SYN packets to 1360.
+#
+throttle_tcp6_mss_for_https=false
+min_tcp6_mss_for_https_val=1280
+
+# ip6t-firewall-server,ipt-firewall-server:
+#     some restrictions on HTTP connections to counteract attacks.
+#
+# The default value used to be set to '30'
+#
+set_max_new_http_conn_per_ip_per_second=true
+default_max_http_new_conn_per_ip_per_second=200
+
+# The default value used to be set to '50'
+#
+set_max_concurrent_http_conn_per_ip=true
+default_max_concurrent_http_conn_per_ip=100
+
+# The default value used to be set to '200'
+#
+set_max_new_http_conn_per_second=true
+default_max_new_http_conn_per_second=400
+
+# ip6t-firewall-server:
+#     Prefix length for entries in 'ban_ipv6.list' given without mask.
+#
+default_ban_ipv6_mask=128
+
+
 # - Dovecot Service
 # -
 dovecot_external_auth_port="44444"
@@ -85,20 +117,20 @@ default_jitsi_dovecout_auth_port="$dovecot_external_auth_port"
 default_jibri_out_port=5222
 # default_outbound_streaming_tcp_ports
 #
-#    - outbound port 1935/TCP : outbound streaming over RTMP to most 
+#    - outbound port 1935/TCP : outbound streaming over RTMP to most
 #      streaming providers such as YouTube Live, Vimeo or Twitch
 #
-#    - outbound port 1936/TCP  : outbound streaming over RTMP to LinkedIn 
+#    - outbound port 1936/TCP  : outbound streaming over RTMP to LinkedIn
 #      Live (port 1935 is also used for RTMP streaming to LinkedIn)
 #
-#    - outbound ports 2935/TCP and 2396/TCP : outbound streaming over 
+#    - outbound ports 2935/TCP and 2396/TCP : outbound streaming over
 #      RTMPS to LinkedIn Live
 #
-#    - outbound port 443/TCP (HTTPS) : used for authentication with the 
+#    - outbound port 443/TCP (HTTPS) : used for authentication with the
-#      built-in providers such as YouTube Live, Facebook Live, Ustream, 
+#      built-in providers such as YouTube Live, Facebook Live, Ustream,
 #      Livestream, and Twitch
 #
-#    - outbound port 53/UDP (DNS) used for DNS lookups converting 
+#    - outbound port 53/UDP (DNS) used for DNS lookups converting
 #      hostnames to IP addresses
 #
 default_outbound_streaming_tcp_ports="1935,1936,2935,2396"

roles/ipt-server/files/etc/ipt-firewall/include_functions.conf

@@ -73,6 +73,54 @@ containsElement () {
    return 1
 }
 
+## - Expand a given IPv6 address (parameter 1) to 32 hex digits without colons.
+## - Returns 1 if the address cannot be parsed.
+## -
+ipv6_expand() {
+   local _addr="${1,,}"
+   local _head _tail _group _n _out=""
+   local -a _h=() _t=()
+
+   if [[ "$_addr" == *::* ]] ; then
+      _head="${_addr%%::*}"
+      _tail="${_addr#*::}"
+      [[ "$_tail" == *::* ]] && return 1
+      [[ -n "$_head" ]] && IFS=':' read -ra _h <<< "$_head"
+      [[ -n "$_tail" ]] && IFS=':' read -ra _t <<< "$_tail"
+      _n=$(( 8 - ${#_h[@]} - ${#_t[@]} ))
+      [[ $_n -lt 1 ]] && return 1
+      for (( ; _n > 0; _n-- )) ; do
+         _h+=("0")
+      done
+      _h+=("${_t[@]}")
+   else
+      IFS=':' read -ra _h <<< "$_addr"
+   fi
+
+   [[ ${#_h[@]} -eq 8 ]] || return 1
+   for _group in "${_h[@]}" ; do
+      [[ "$_group" =~ ^[0-9a-f]{1,4}$ ]] || return 1
+      _out+="$(printf '%04x' "0x$_group")"
+   done
+
+   echo "$_out"
+}
+
+## - Check if a given IPv6 address (parameter 1) lies within the network
+## - given by address (parameter 2) and prefix length (parameter 3).
+## -
+ipv6_in_net() {
+   local _a _n _full _rest
+   _a="$(ipv6_expand "$1")" || return 1
+   _n="$(ipv6_expand "$2")" || return 1
+   _full=$(( $3 / 4 ))
+   _rest=$(( $3 % 4 ))
+
+   [[ "${_a:0:_full}" == "${_n:0:_full}" ]] || return 1
+   [[ $_rest -eq 0 ]] && return 0
+   (( (0x${_a:_full:1} >> (4 - _rest)) == (0x${_n:_full:1} >> (4 - _rest)) ))
+}
+
 is_number() {
 
    return $(test ! -z "${1##*[!0-9]*}" > /dev/null 2>&1);

roles/ipt-server/files/etc/ipt-firewall/post_declarations.conf

@@ -60,7 +60,7 @@ done
 # ---
 declare -a ext_ip_arr
 for _ip in $ext_ips ; do
-   host_ip_arr+=("$_ip")
+   ext_ip_arr+=("$_ip")
 done
 
 # ---

roles/ipt-server/files/usr/local/sbin/ip6t-firewall-server

@@ -448,6 +448,29 @@ fi
 
 
 
+# ---
+# - ICMPv6 Neighbor Discovery and Packet Too Big
+# ---
+# Accept these before any rule blocking by source address (blocked_ips,
+# ban_ipv6.list). Otherwise a blocked network containing a router of the
+# own link breaks neighbor discovery - the router can no longer reach this host.
+#
+# 2  = packet-too-big
+# 133= router-solicitation
+# 134= router-advertisement
+# 135= neighbor-solicitation
+# 136= neighbor-advertisement
+# ---
+echononl "\tICMPv6 neighbor discovery / packet-too-big (before blocking rules).."
+for t in 2 133 134 135 136 ; do
+   $ip6t -A INPUT -p ipv6-icmp --icmpv6-type $t -j ACCEPT
+done
+if $kernel_forward_between_interfaces ; then
+   $ip6t -A FORWARD -p ipv6-icmp --icmpv6-type 2 -j ACCEPT
+fi
+echo_done
+
+
 # -------------
 # --- Block IPs / Networks / Interfaces
 # -------------
@@ -509,6 +532,19 @@ if [[ -f "$conf_ban_ipv6_list" ]] ; then
 
 	declare -a ban_ipv6_arr=()
    declare -a no_valid_ipv6=()
+   declare -a own_ipv6_banned_arr=()
+
+   if [[ -z "$ban_ipv6_mask" || ! "$ban_ipv6_mask" =~ ^[0-9]+$ ]] || [[ $ban_ipv6_mask -gt 128 ]] ; then
+      ban_ipv6_mask=${default_ban_ipv6_mask:-128}
+   fi
+
+   # Own global IPv6 addresses (read at runtime, also covers SLAAC addresses).
+   # Entries covering one of them would block the own prefix including its routers.
+   #
+   declare -a own_ipv6_arr=()
+   for _own_ip in $(ip -6 -o addr show scope global | awk '{split($4, a, "/"); print a[1]}') ; do
+      own_ipv6_arr+=("$_own_ip")
+   done
 
 	# Regex valid ipv6 address
 	#
@@ -568,7 +604,7 @@ if [[ -f "$conf_ban_ipv6_list" ]] ; then
             fi
          fi
       else
-         mask=64
+         mask=$ban_ipv6_mask
 			is_valid_mask=true
       fi
 
@@ -586,6 +622,22 @@ if [[ -f "$conf_ban_ipv6_list" ]] ; then
 				continue
 			fi
 
+         # Never ban a network containing an own address
+         #
+         _covers_own_ip=false
+         for _own_ip in "${own_ipv6_arr[@]}" ; do
+            if ipv6_in_net "$_own_ip" "$ipv6" "$mask" ; then
+               _covers_own_ip=true
+               break
+            fi
+         done
+         if $_covers_own_ip ; then
+            if ! containsElement "$_ip" "${own_ipv6_banned_arr[@]}" ; then
+               own_ipv6_banned_arr+=("$_ip")
+            fi
+            continue
+         fi
+
          for _dev in ${ext_if_arr[@]} ; do
             if $log_blocked_ip || $log_all ; then
                $ip6t -A INPUT -i $_dev -s $_ip -j $LOG_TARGET $tag_log_prefix "$log_prefix Blocked by ban_ipv6.list: "
@@ -614,6 +666,9 @@ if [[ -f "$conf_ban_ipv6_list" ]] ; then
    if [[ ${#no_valid_ipv6_arr[@]} -gt 0  ]]; then
       warn "Ignored: ${no_valid_ipv6_arr[@]}"
    fi
+   if [[ ${#own_ipv6_banned_arr[@]} -gt 0  ]]; then
+      warn "Ignored (covers own address): ${own_ipv6_banned_arr[@]}"
+   fi
 else
    echo_skipped
 fi
@@ -644,6 +699,59 @@ echo_skipped
 #echo_done
 
 
+# ---
+# - IPv6 TCP MSS adjustment for incoming HTTPS connections
+# ---
+# The IPv6 path MTU can be smaller than the interface MTU.
+# Clamp the advertised MSS of incoming HTTPS SYN packets to 1360.
+# This prevents oversized TCP segments in server responses.
+#
+# Tested on oolm-shop on 2026-10-26.
+# ---
+
+echononl "\tAdjust IPv6 TCP MSS for HTTPS connections"
+
+if $throttle_tcp6_mss_for_https ; then
+
+   if [[ -n "$tcp6_mss_for_https_val" ]] ; then
+
+      # Notice:
+      #
+      #  - take care 'tcp6_mss_for_https_val' consists only of digits (is a natural number)
+      #
+      #  - 1280 is the minimum IPv6 packet size that all routers must be able to process
+      #
+      if [[ "$tcp6_mss_for_https_val" =~ ^[0-9]+$ ]] ; then
+
+         if [[ "$tcp6_mss_for_https_val" -lt 1280 ]]; then
+
+            tcp6_mss_for_https_val=$min_tcp6_mss_for_https_val
+
+         fi
+
+      fi
+
+   else
+
+      tcp6_mss_for_https_val=$min_tcp6_mss_for_https_val
+   fi
+
+   for _dev in ${ext_if_arr[@]} ; do
+      $ip6t -t mangle -A PREROUTING -i $_dev \
+         -p tcp --dport 443 \
+         --tcp-flags SYN,RST SYN \
+         -j TCPMSS --set-mss $tcp6_mss_for_https_val
+   done
+
+   echo_done
+
+else
+
+   echo_skipped
+
+fi
+
+
 # ---
 # Drop TCP packets that are new and are not SYN
 # ---
@@ -709,13 +817,18 @@ echo_done
 # ---
 
 echononl "\tBlock spoofed (own ip) packets"
+
+# Note:
+#   Exclude loopback - local traffic to an own address (e.g. a web application
+#   requesting its own domain) passes PREROUTING via 'lo' with src = dst.
+#
 if $log_spoofed || $log_all ; then
    for _ip in ${ext_ip_arr[@]} ; do
-      $ip6t -t mangle -A PREROUTING -s $_ip -d $_ip -j $LOG_TARGET $tag_log_prefix "$log_prefix Spoofed (own ip): "
+      $ip6t -t mangle -A PREROUTING ! -i lo -s $_ip -d $_ip -j $LOG_TARGET $tag_log_prefix "$log_prefix Spoofed (own ip): "
    done
 fi
 for _ip in ${ext_ip_arr[@]} ; do
-   $ip6t -t mangle -A PREROUTING -s $_ip -d $_ip -j DROP
+   $ip6t -t mangle -A PREROUTING ! -i lo -s $_ip -d $_ip -j DROP
 done
 echo_done
 
@@ -2057,6 +2170,134 @@ echo_done
 # - HTTP(S) (local) Webserver
 # ---
 
+echo ""
+
+# Note:
+#   The following rules only DROP/REJECT excess connections - they never ACCEPT.
+#   Ports are opened exclusively by the rules for 'http_server_ips' below.
+#   Without local webserver (empty 'http_server_ips') no rules are created.
+#
+echononl "\t\tA maximum number new connections per second per IP"
+
+if [[ ${#http_server_ip_arr[@]} -gt 0 ]] && $set_max_new_http_conn_per_ip_per_second ; then
+
+   if [[ -z "$max_http_new_conn_per_ip_per_second" || ! "$max_http_new_conn_per_ip_per_second" =~ ^[0-9]+$ ]]; then
+
+      max_http_new_conn_per_ip_per_second=$default_max_http_new_conn_per_ip_per_second
+
+   fi
+
+   burst_http_new_conn_per_ip_per_second=$((max_http_new_conn_per_ip_per_second * 2))
+
+   if $log_rejected || $log_all ; then
+      $ip6t -A INPUT -p tcp -m multiport --dports $http_ports -m conntrack --ctstate NEW \
+      -m hashlimit --hashlimit-name http_v6_log --hashlimit-mode srcip \
+      --hashlimit-above ${max_http_new_conn_per_ip_per_second}/second \
+      --hashlimit-burst $burst_http_new_conn_per_ip_per_second \
+      --hashlimit-htable-expire 600000 \
+      -m limit --limit 10/second --limit-burst 20 \
+      -j $LOG_TARGET $tag_log_prefix "$log_prefix more then $max_http_new_conn_per_ip_per_second new connections per second"
+   fi
+
+   # HTTP/HTTPS: neue Verbindungen pro Quell-IP begrenzen
+   # Über 'max_http_new_conn_per_ip_per_second' neue Verbindungen/s pro IP werden gedroppt
+   # Eintrag wird nach 600000 ms = 10 Minuten gelöscht (--hashlimit-htable-expire 600000).
+   $ip6t -A INPUT -p tcp -m multiport --dports $http_ports -m conntrack --ctstate NEW \
+   -m hashlimit --hashlimit-name http_v6 --hashlimit-mode srcip \
+   --hashlimit-above ${max_http_new_conn_per_ip_per_second}/second \
+   --hashlimit-burst $burst_http_new_conn_per_ip_per_second  \
+   --hashlimit-htable-expire 600000 -j DROP
+
+   echo_done
+
+else
+
+   echo_skipped
+
+fi
+
+
+echononl "\t\tA maximum number of concurrent TCP connections per IP"
+
+if [[ ${#http_server_ip_arr[@]} -gt 0 ]] && $set_max_concurrent_http_conn_per_ip ; then
+
+   if [[ -z "$max_concurrent_http_conn_per_ip" || ! "$max_concurrent_http_conn_per_ip" =~ ^[0-9]+$ ]]; then
+
+      max_concurrent_http_conn_per_ip=$default_max_concurrent_http_conn_per_ip
+
+   fi
+
+   if $log_rejected || $log_all ; then
+      $ip6t -A INPUT -p tcp -m multiport --dports $http_ports --syn \
+      -m connlimit --connlimit-above $max_concurrent_http_conn_per_ip --connlimit-mask 128 \
+      -m limit --limit 10/second --limit-burst 20 \
+      -j $LOG_TARGET $tag_log_prefix "$log_prefix more then $max_concurrent_http_conn_per_ip concurrent connections per IP."
+   fi
+
+   # HTTP/HTTPS: gleichzeitige Verbindungen pro IP begrenzen
+   # Mehr als 'max_concurrent_http_conn_per_ip' parallele TCP-Verbindungen pro IP ablehnen
+   #
+   # Limit gilt pro einzelner IPv6-Adresse (--connlimit-mask 128) (z.bsp.  2a01:599:108:40b0:e1a9:170b:ba18:fd58/128)
+   $ip6t -A INPUT -p tcp -m multiport --dports $http_ports --syn \
+   -m connlimit --connlimit-above $max_concurrent_http_conn_per_ip --connlimit-mask 128 \
+   -j REJECT --reject-with tcp-reset
+
+   echo_done
+
+else
+
+   echo_skipped
+
+fi
+
+
+echononl "\t\tA maximum number of new TCP handshakes per second."
+
+if [[ ${#http_server_ip_arr[@]} -gt 0 ]] && $set_max_new_http_conn_per_second ; then
+
+   if [[ -z "$max_new_http_conn_per_second" || ! "$max_new_http_conn_per_second" =~ ^[0-9]+$ ]]; then
+
+      max_new_http_conn_per_second=$default_max_new_http_conn_per_second
+
+   fi
+
+   burst_max_new_http_conn_per_second=$((2 * max_new_http_conn_per_second))
+
+   # SYN-Rate begrenzen (global, alle Quell-IPs zusammen)
+   #
+   # hashlimit ohne '--hashlimit-mode' verwendet einen einzigen Bucket für alle
+   # Pakete. SYN-Pakete oberhalb des Limits werden gedroppt; alles darunter
+   # läuft weiter zu den Regeln für 'http_server_ips' (kein ACCEPT hier!).
+   #
+   # Kurzfristig auch bis zu 'burst_max_new_http_conn_per_second' SYN-Pakete erlaubt.
+   if $log_rejected || $log_all ; then
+      $ip6t -A INPUT -p tcp -m multiport --dports $http_ports \
+         --syn \
+         -m hashlimit --hashlimit-name http_v6_syn_log \
+         --hashlimit-above ${max_new_http_conn_per_second}/second \
+         --hashlimit-burst $burst_max_new_http_conn_per_second \
+         -m limit --limit 10/second --limit-burst 20 \
+         -j $LOG_TARGET $tag_log_prefix "$log_prefix SYN-Overflow."
+   fi
+
+   $ip6t -A INPUT -p tcp -m multiport --dports $http_ports \
+      --syn \
+      -m hashlimit --hashlimit-name http_v6_syn \
+      --hashlimit-above ${max_new_http_conn_per_second}/second \
+      --hashlimit-burst $burst_max_new_http_conn_per_second \
+      -j DROP
+
+   echo_done
+
+else
+
+   echo_skipped
+
+fi
+
+echo ""
+
+
 echononl "\t\tHTTP(S) (local) Webserver"
 
 if [[ ${#http_server_ip_arr[@]} -gt 0 ]] || [[ ${#forward_http_server_ip_arr[@]} -gt 0 ]]  ; then
@@ -2089,12 +2330,22 @@ if [[ ${#mm_server_ip_arr[@]} -gt 0 ]] || [[ ${#forward_mm_server_ip_arr[@]} -gt
    if [[ ${#mm_server_ip_arr[@]} -gt 0 ]] ; then
       for _ip in ${mm_server_ip_arr[@]} ; do
          $ip6t -A INPUT -p udp -d $_ip -m multiport --dports $mm_udp_ports_in -m conntrack --ctstate NEW -j ACCEPT
+         if [[ -n "$mm_tcp_ports_in" ]] ; then
+            $ip6t -A INPUT -p tcp -d $_ip -m multiport --dports $mm_tcp_ports_in -m conntrack --ctstate NEW -j ACCEPT
+         else
+            $ip6t -A INPUT -p tcp -d $_ip -m multiport --dports $mm_udp_ports_in -m conntrack --ctstate NEW -j ACCEPT
+         fi
          $ip6t -A OUTPUT -p udp -s $_ip -m multiport --dports $mm_udp_ports_out -m conntrack --ctstate NEW -j ACCEPT
       done
 
       if  [[ ${#forward_mm_server_ip_arr[@]} -gt 0 ]] && $kernel_forward_between_interfaces ; then
          for _ip in ${forward_mm_server_ip_arr[@]} ; do
             $ip6t -A FORWARD -p udp -d $_ip -m multiport --dports $mm_udp_ports_in -m conntrack --ctstate NEW -j ACCEPT
+            if [[ -n "$mm_tcp_ports_in" ]] ; then
+               $ip6t -A FORWARD -p tcp -d $_ip -m multiport --dports $mm_tcp_ports_in -m conntrack --ctstate NEW -j ACCEPT
+            else
+               $ip6t -A FORWARD -p tcp -d $_ip -m multiport --dports $mm_udp_ports_in -m conntrack --ctstate NEW -j ACCEPT
+            fi
             $ip6t -A FORWARD -p udp -s $_ip -m multiport --dports $mm_udp_ports_out -m conntrack --ctstate NEW -j ACCEPT
          done
       fi

roles/ipt-server/files/usr/local/sbin/ipt-firewall-server

@@ -814,13 +814,18 @@ echo_done
 # ---
 
 echononl "\tBlock spoofed (own ip) packets"
+
+# Note:
+#   Exclude loopback - local traffic to an own address (e.g. a web application
+#   requesting its own domain) passes PREROUTING via 'lo' with src = dst.
+#
 if $log_spoofed || $log_all ; then
    for _ip in ${ext_ip_arr[@]} ; do
-      $ipt -t mangle -A PREROUTING -s $_ip -d $_ip -j $LOG_TARGET $tag_log_prefix "$log_prefix Spoofed (own ip): "
+      $ipt -t mangle -A PREROUTING ! -i lo -s $_ip -d $_ip -j $LOG_TARGET $tag_log_prefix "$log_prefix Spoofed (own ip): "
    done
 fi
 for _ip in ${ext_ip_arr[@]} ; do
-   $ipt -t mangle -A PREROUTING -s $_ip -d $_ip -j DROP
+   $ipt -t mangle -A PREROUTING ! -i lo -s $_ip -d $_ip -j DROP
 done
 echo_done
 
@@ -2241,6 +2246,134 @@ echo_done
 # - HTTP(S) (local) Webserver
 # ---
 
+echo ""
+
+# Note:
+#   The following rules only DROP/REJECT excess connections - they never ACCEPT.
+#   Ports are opened exclusively by the rules for 'http_server_ips' below.
+#   Without local webserver (empty 'http_server_ips') no rules are created.
+#
+echononl "\t\tA maximum number new connections per second per IP"
+
+if [[ ${#http_server_ip_arr[@]} -gt 0 ]] && $set_max_new_http_conn_per_ip_per_second ; then
+
+   if [[ -z "$max_http_new_conn_per_ip_per_second" || ! "$max_http_new_conn_per_ip_per_second" =~ ^[0-9]+$ ]]; then
+
+      max_http_new_conn_per_ip_per_second=$default_max_http_new_conn_per_ip_per_second
+
+   fi
+
+   burst_http_new_conn_per_ip_per_second=$((max_http_new_conn_per_ip_per_second * 2))
+
+   if $log_rejected || $log_all ; then
+      $ipt -A INPUT -p tcp -m multiport --dports $http_ports -m conntrack --ctstate NEW \
+      -m hashlimit --hashlimit-name http_v4_log --hashlimit-mode srcip \
+      --hashlimit-above ${max_http_new_conn_per_ip_per_second}/second \
+      --hashlimit-burst $burst_http_new_conn_per_ip_per_second \
+      --hashlimit-htable-expire 600000 \
+      -m limit --limit 10/second --limit-burst 20 \
+      -j $LOG_TARGET $tag_log_prefix "$log_prefix more then $max_http_new_conn_per_ip_per_second new connections per second"
+   fi
+
+   # HTTP/HTTPS: neue Verbindungen pro Quell-IP begrenzen
+   # Über 'max_http_new_conn_per_ip_per_second' neue Verbindungen/s pro IP werden gedroppt
+   # Eintrag wird nach 600000 ms = 10 Minuten gelöscht (--hashlimit-htable-expire 600000).
+   $ipt -A INPUT -p tcp -m multiport --dports $http_ports -m conntrack --ctstate NEW \
+   -m hashlimit --hashlimit-name http_v4 --hashlimit-mode srcip \
+   --hashlimit-above ${max_http_new_conn_per_ip_per_second}/second \
+   --hashlimit-burst $burst_http_new_conn_per_ip_per_second  \
+   --hashlimit-htable-expire 600000 -j DROP
+
+   echo_done
+
+else
+
+   echo_skipped
+
+fi
+
+
+echononl "\t\tA maximum number of concurrent TCP connections per IP"
+
+if [[ ${#http_server_ip_arr[@]} -gt 0 ]] && $set_max_concurrent_http_conn_per_ip ; then
+
+   if [[ -z "$max_concurrent_http_conn_per_ip" || ! "$max_concurrent_http_conn_per_ip" =~ ^[0-9]+$ ]]; then
+
+      max_concurrent_http_conn_per_ip=$default_max_concurrent_http_conn_per_ip
+
+   fi
+
+   if $log_rejected || $log_all ; then
+      $ipt -A INPUT -p tcp -m multiport --dports $http_ports --syn \
+      -m connlimit --connlimit-above $max_concurrent_http_conn_per_ip --connlimit-mask 32 \
+      -m limit --limit 10/second --limit-burst 20 \
+      -j $LOG_TARGET $tag_log_prefix "$log_prefix more then $max_concurrent_http_conn_per_ip concurrent connections per IP."
+   fi
+
+   # HTTP/HTTPS: gleichzeitige Verbindungen pro IP begrenzen
+   # Mehr als 'max_concurrent_http_conn_per_ip' parallele TCP-Verbindungen pro IP ablehnen
+   #
+   # Limit gilt pro einzelner IPv4-Adresse (--connlimit-mask 32)
+   $ipt -A INPUT -p tcp -m multiport --dports $http_ports --syn \
+   -m connlimit --connlimit-above $max_concurrent_http_conn_per_ip --connlimit-mask 32 \
+   -j REJECT --reject-with tcp-reset
+
+   echo_done
+
+else
+
+   echo_skipped
+
+fi
+
+
+echononl "\t\tA maximum number of new TCP handshakes per second."
+
+if [[ ${#http_server_ip_arr[@]} -gt 0 ]] && $set_max_new_http_conn_per_second ; then
+
+   if [[ -z "$max_new_http_conn_per_second" || ! "$max_new_http_conn_per_second" =~ ^[0-9]+$ ]]; then
+
+      max_new_http_conn_per_second=$default_max_new_http_conn_per_second
+
+   fi
+
+   burst_max_new_http_conn_per_second=$((2 * max_new_http_conn_per_second))
+
+   # SYN-Rate begrenzen (global, alle Quell-IPs zusammen)
+   #
+   # hashlimit ohne '--hashlimit-mode' verwendet einen einzigen Bucket für alle
+   # Pakete. SYN-Pakete oberhalb des Limits werden gedroppt; alles darunter
+   # läuft weiter zu den Regeln für 'http_server_ips' (kein ACCEPT hier!).
+   #
+   # Kurzfristig auch bis zu 'burst_max_new_http_conn_per_second' SYN-Pakete erlaubt.
+   if $log_rejected || $log_all ; then
+      $ipt -A INPUT -p tcp -m multiport --dports $http_ports \
+         --syn \
+         -m hashlimit --hashlimit-name http_v4_syn_log \
+         --hashlimit-above ${max_new_http_conn_per_second}/second \
+         --hashlimit-burst $burst_max_new_http_conn_per_second \
+         -m limit --limit 10/second --limit-burst 20 \
+         -j $LOG_TARGET $tag_log_prefix "$log_prefix SYN-Overflow."
+   fi
+
+   $ipt -A INPUT -p tcp -m multiport --dports $http_ports \
+      --syn \
+      -m hashlimit --hashlimit-name http_v4_syn \
+      --hashlimit-above ${max_new_http_conn_per_second}/second \
+      --hashlimit-burst $burst_max_new_http_conn_per_second \
+      -j DROP
+
+   echo_done
+
+else
+
+   echo_skipped
+
+fi
+
+echo ""
+
+
 echononl "\t\tHTTP(S) (local) Webserver"
 
 if [[ ${#http_server_ip_arr[@]} -gt 0 ]] || [[ ${#forward_http_server_ip_arr[@]} -gt 0 ]]  ; then
@@ -2273,12 +2406,22 @@ if [[ ${#mm_server_ip_arr[@]} -gt 0 ]] || [[ ${#forward_mm_server_ip_arr[@]} -gt
    if [[ ${#mm_server_ip_arr[@]} -gt 0 ]] ; then
       for _ip in ${mm_server_ip_arr[@]} ; do
          $ipt -A INPUT -p udp -d $_ip -m multiport --dports $mm_udp_ports_in -m conntrack --ctstate NEW -j ACCEPT
-   $ipt -A OUTPUT -p udp -s $_ip -m multiport --dports $mm_udp_ports_out -m conntrack --ctstate NEW -j ACCEPT
+         if [[ -n "$mm_tcp_ports_in" ]] ; then
+            $ipt -A INPUT -p tcp -d $_ip -m multiport --dports $mm_tcp_ports_in -m conntrack --ctstate NEW -j ACCEPT
+         else
+            $ipt -A INPUT -p tcp -d $_ip -m multiport --dports $mm_udp_ports_in -m conntrack --ctstate NEW -j ACCEPT
+         fi
+         $ipt -A OUTPUT -p udp -s $_ip -m multiport --dports $mm_udp_ports_out -m conntrack --ctstate NEW -j ACCEPT
       done
 
       if  [[ ${#forward_mm_server_ip_arr[@]} -gt 0 ]] && $kernel_activate_forwarding ; then
          for _ip in ${forward_mm_server_ip_arr[@]} ; do
             $ipt -A FORWARD -p udp -d $_ip -m multiport --dports $mm_udp_ports_in -m conntrack --ctstate NEW -j ACCEPT
+            if [[ -n "$mm_tcp_ports_in" ]] ; then
+               $ipt -A FORWARD -p tcp -d $_ip -m multiport --dports $mm_tcp_ports_in -m conntrack --ctstate NEW -j ACCEPT
+            else
+               $ipt -A FORWARD -p tcp -d $_ip -m multiport --dports $mm_udp_ports_in -m conntrack --ctstate NEW -j ACCEPT
+            fi
             $ipt -A FORWARD -p udp -s $_ip -m multiport --dports $mm_udp_ports_out -m conntrack --ctstate NEW -j ACCEPT
          done
       fi

roles/ipt-server/tasks/main.yml

@@ -107,6 +107,8 @@
     owner: root
     group: root
     mode: "0750"
+  notify:
+    - Restart IPv4 Firewall
 
 - name: Deploy ip6t-firewall-server
   copy:
@@ -115,6 +117,8 @@
     owner: root
     group: root
     mode: "0750"
+  notify:
+    - Restart IPv6 Firewall
 
 
 # ===
@@ -134,6 +138,11 @@
     - logging_ipv4.conf
     - logging_ipv6.conf
     - post_declarations.conf
+  # Shared files are sourced by both scripts; logging_ipv4/6 only by one,
+  # but restarting both keeps this simple.
+  notify:
+    - Restart IPv4 Firewall
+    - Restart IPv6 Firewall
 
 
 # ===

roles/ipt-server/templates/etc/ipt-firewall/main_ipv4.conf.j2

@@ -137,6 +137,16 @@ http_ports="{{ fw_http_ports }}"
 log_cgi_traffic_out={{ fw_log_cgi_traffic_out | lower }}
 cgi_script_users="{{ fw_cgi_script_users }}"
 
+# Restrictions on HTTP(S) connections to counteract attacks
+set_max_new_http_conn_per_ip_per_second={{ fw_set_max_new_http_conn_per_ip_per_second | lower }}
+max_http_new_conn_per_ip_per_second="{{ fw_max_http_new_conn_per_ip_per_second }}"
+
+set_max_concurrent_http_conn_per_ip={{ fw_set_max_concurrent_http_conn_per_ip | lower }}
+max_concurrent_http_conn_per_ip="{{ fw_max_concurrent_http_conn_per_ip }}"
+
+set_max_new_http_conn_per_second={{ fw_set_max_new_http_conn_per_second | lower }}
+max_new_http_conn_per_second="{{ fw_max_new_http_conn_per_second }}"
+
 
 # -------------
 # --- Services: Mattermost
@@ -145,6 +155,7 @@ cgi_script_users="{{ fw_cgi_script_users }}"
 mm_server_ips="{{ fw_mm_server_ips }}"
 forward_mm_server_ips="{{ fw_forward_mm_server_ips }}"
 mm_udp_ports_in="{{ fw_mm_udp_ports_in }}"
+mm_tcp_ports_in="{{ fw_mm_tcp_ports_in }}"
 mm_udp_ports_out="{{ fw_mm_udp_ports_out }}"
 
 
@@ -305,7 +316,7 @@ portforward_udp="{{ fw_portforward_udp_v4 }}"
 # --- Blocked IPs / Ports
 # -------------
 
-blocked_ips="{{ fw_blocked_ips }}"
+blocked_ips="{{ fw_blocked_ips_v4 }}"
 block_tcp_ports="{{ fw_block_tcp_ports }}"
 block_udp_ports="{{ fw_block_udp_ports }}"
 

roles/ipt-server/templates/etc/ipt-firewall/main_ipv6.conf.j2

@@ -127,6 +127,20 @@ http_ports="{{ fw_http_ports }}"
 log_cgi_traffic_out={{ fw_log_cgi_traffic_out | lower }}
 cgi_script_users="{{ fw_cgi_script_users }}"
 
+# Restrictions on HTTP(S) connections to counteract attacks
+set_max_new_http_conn_per_ip_per_second={{ fw_set_max_new_http_conn_per_ip_per_second | lower }}
+max_http_new_conn_per_ip_per_second="{{ fw_max_http_new_conn_per_ip_per_second }}"
+
+set_max_concurrent_http_conn_per_ip={{ fw_set_max_concurrent_http_conn_per_ip | lower }}
+max_concurrent_http_conn_per_ip="{{ fw_max_concurrent_http_conn_per_ip }}"
+
+set_max_new_http_conn_per_second={{ fw_set_max_new_http_conn_per_second | lower }}
+max_new_http_conn_per_second="{{ fw_max_new_http_conn_per_second }}"
+
+# Clamp the advertised MSS of incoming HTTPS SYN packets
+throttle_tcp6_mss_for_https={{ fw_throttle_tcp6_mss_for_https | lower }}
+tcp6_mss_for_https_val="{{ fw_tcp6_mss_for_https_val }}"
+
 
 # -------------
 # --- Services: Mattermost
@@ -135,6 +149,7 @@ cgi_script_users="{{ fw_cgi_script_users }}"
 mm_server_ips="{{ fw_mm_server_ips }}"
 forward_mm_server_ips="{{ fw_forward_mm_server_ips }}"
 mm_udp_ports_in="{{ fw_mm_udp_ports_in }}"
+mm_tcp_ports_in="{{ fw_mm_tcp_ports_in }}"
 mm_udp_ports_out="{{ fw_mm_udp_ports_out }}"
 
 
@@ -295,7 +310,11 @@ portforward_udp="{{ fw_portforward_udp_v6 }}"
 # --- Blocked IPs / Ports
 # -------------
 
-blocked_ips="{{ fw_blocked_ips }}"
+blocked_ips="{{ fw_blocked_ips_v6 }}"
+
+# Prefix length for entries in ban_ipv6.list given without mask
+ban_ipv6_mask="{{ fw_ban_ipv6_mask }}"
+
 block_tcp_ports="{{ fw_block_tcp_ports }}"
 block_udp_ports="{{ fw_block_udp_ports }}"