Differences

This shows you the differences between two versions of the page.

--- advanced-firewall [2024/11/27 00:39] – [Multicast] -Formatting, condense, add explanation of Force IGMPv2 setting hogwild
+++ advanced-firewall [2026/07/23 17:43] (current) – Condense, clarity for Enable TCP Syn Packets hogwild
@@ Line 2: / Line 2: @@
 The Firewall page allows you to configure options to protect or facilitate various types of network communications.
 ===== Firewall =====
-{{:pasted:20220118-182859.png}} \\
+{{::advanced-firewall-1.jpg?364}} \\
  \\ **WAN interfaces respond to ping and traceroute:  **lets your device reply to ping/traceroute request packets from Internet hosts.
@@ Line 16: / Line 15: @@
 **Limit communication to: **specifies the maximum number of requests per second to which the Firewall replies.
-Setting a limit is recommended to prevent DDoS attacks.\\   \\   \\ {{:pasted:20220118-183317.png}}\\
+Setting a limit is recommended to prevent DDoS attacks.\\   \\   \\
- \\
+{{::advanced-firewall-2.jpg?545}} \\
-**Enable TCP SYN cookies:  **uses "SYN cookies" to protect the router from SYN Flood attacks.
+ \\ **Enable TCP SYN cookies:  **uses "SYN cookies" to protect the router from SYN Flood attacks.
-It encodes information from the SYN packet into the (SYN/ACK) response. It is a standard method for preventing SYN floods. However, it has limitations that may cause issues with some old TCP/IP stacks.
+This uses a standard method for preventing SYN floods. It encodes information from the SYN packet into the (SYN/ACK) response. Its limitations may cause issues with some old TCP/IP stacks. \\
  \\
@@ Line 32: / Line 31: @@
 **Allow DHCP Spoofing: **makes FreshTomato accept/process packets from DHCP servers with different IP than the one it advertises.
-Such behaviour is often categorized as a DHCP spoofing attack, but rarely, might be legitimate. Using this lowers security.\\  \\
+Such behaviour is often categorized as a DHCP spoofing attack, but rarely, might be legitimate. Using this lowers security.
-**Smart MTU black hole detection:** this feature detects ICMP black holes and smartly tries to adjust the path MTU.
+ \\
-For details on MTU and black holes, see this blog post: [[https://blog.cloudflare.com/path-mtu-discovery-in-practice/|The CloudFlare Blog: Path MTU Discovery in Practice]]
+**Smart MTU black hole detection:** detects ICMP black holes and smartly tries to adjust the path MTU.
+For details on MTU and black holes, see this blog post: [[https://blog.cloudflare.com/path-mtu-discovery-in-practice/|The CloudFlare Blog: Path MTU Discovery in Practice]] \\
+\\
+**TCP MSS Clamping:**
+This adjusts the Maximum Segment Size of forwarded TCP connections on WAN and VPN interfaces to match the discovered path MTU.
+This helps avoid MTU-related connection problems, especially on PPPoE links, VPN tunnels, IPv6 tunnels, or networks with blocked ICMP fragmentation-needed messages.
+Disabling this option reduces the number of firewall rules and may slightly improve performance on low-end routers, but can cause connection stalls or TLS handshake timeouts on links with reduced MTU.
+Recommended setting: enabled, unless MTU/MSS is handled manually or the network works reliably without MSS clamping.
 ===== NAT =====
-**NAT loopback:** lets LAN devices access each other via the router's WAN interface. Also known as "Hairpinning", it's often used when connecting to the DDNS domain of your router via the LAN. These days, this setting is almost never needed. Also, it can create speed bottlenecks.
+**NAT loopback:** lets LAN devices access each other via the router's WAN interface.
+Also known as "Hairpinning", it's often used when connecting to the DDNS domain of your router via the LAN. These days, this setting is almost never needed. Also, it can create speed bottlenecks.
  \\
@@ Line 55: / Line 70: @@
 \\
-**NAT target: **defines how NAT is implemented in loopback situations. Masquerade is the default, but involves an additional lookup, and the mapping is done towards an interface. SNAT is minutely faster, as its NAT mapping points directly to the destination IP and thus bypasses the lookup stage. However, SNAT is less reliable than Masquerade.
+**NAT target: **defines how NAT is implemented in loopback situations.
- \\
+Masquerade is the default, but involves an additional lookup, and the mapping is done towards an interface. SNAT is minutely faster, as its NAT mapping points directly to the destination IP, thus bypassing the lookup stage. However, SNAT is less reliable than Masquerade.\\
 ===== Multicast =====
- \\ \\ {{:pasted:20220118-185509.png?742}}\\  \\
+ \\ {{:pasted:20220118-185509.png?742}}\\  \\
 **Enable IGMP proxy: **enables the Internet Group Management Protocol service.
@@ Line 107: / Line 121: @@
 **Max clients: **the maximum number of simultaneous Udpxy clients.
-Udpxy is is a lightweight protocol, so it works well for a limited number of clients. You might want to impose a maximum limit.
+Udpxy is is a lightweight protocol, so it works well for a limited number of clients. You might want to set a maximum limit.
  \\
 **Udpxy port: **specifies the port on which to receive Udpxy information from your router.\\  \\   \\  {{:pasted:20220118-190844.png}}\\  \\
- \\
 **Efficient Multicast Forwarding (IGMP Snooping): **IGMP snooping makes the router's switch facilitate discovery of Multicast IGMP clients. This helps to send multicast traffic only towards ports with at least one multicast subscriber, reducing overall multicast traffic.

FreshTomato Wiki

User Tools

Site Tools

Differences

Page Tools