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--- advanced-firewall [2024/10/27 22:41] – [Multicast] -Condense hogwild
+++ advanced-firewall [2024/11/27 00:42] (current) – [Multicast] hogwild
@@ Line 8: / Line 8: @@
 {{:pasted:20220118-182859.png}} \\
- \\ **WAN interfaces respond to ping and traceroute:  **lets your device reply to ping/traceroute request packets from Internet hosts. This is needed for //ping //and //traceroute to //work via the Internet. Enabling this also may be needed for proper functioning of some VPN and IPv6 protocols.
+ \\ **WAN interfaces respond to ping and traceroute:  **lets your device reply to ping/traceroute request packets from Internet hosts.
+This is needed for //ping //and //traceroute to //work via the Internet. It also may be needed for proper functioning of some VPN or IPv6 protocols.
  \\
-**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}}\\
+**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}}\\
  \\
-**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.
+**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.
  \\
@@ Line 24: / Line 30: @@
  \\
-**Allow DHCP Spoofing:**
+**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.\\  \\
-**Smart MTU black hole detection:**
+**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]]
 ===== 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 47: / Line 57: @@
 \\
-**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.
  \\
@@ Line 62: / Line 74: @@
  \\
-  * LAN0 - Causes the LAN0 bridge to participate in IGMP proxy.
+  * LAN0 - Causes the LAN0 bridge to join in IGMP proxy.
-  * LAN1 - Causes the LAN1 bridge to participate in IGMP proxy.
+  * LAN1 - Causes the LAN1 bridge to join in IGMP proxy.
-  * LAN2 - Causes the LAN2 bridge to participate in IGMP proxy.
+  * LAN2 - Causes the LAN2 bridge to join in IGMP proxy.
-  * LAN3 - Causes the LAN3 bridge to participate in IGMP proxy.
+  * LAN3 - Causes the LAN3 bridge to join in IGMP proxy.
  \\
-**Enable quick leave:** this IGMP v2 feature lets the router stop streaming multicast to an IP as soon as the device sends a "quick leave" packet.
+**Enable quick leave:** this IGMPv2 feature lets the router stop multicasting to an IP that has sent it a "quick leave" packet.
  \\
-**Custom Configuration:** lets you set advanced parameters for the IGMP proxy daemon. Consult official documentation before using this.\\   \\
+**Custom Configuration:** lets you configure advanced settings for the IGMP proxy daemon. Consult official documentation.\\   \\
  \\ {{:pasted:20220118-190050.png}}\\  \\
-**Enable Udpxy: **like IGMP proxy, Udpxy lets devices on different VLANs to do multicast communications. Since they are similar, use either Udpxy or IGMP proxy, but not both at once.
+**Enable Udpxy: **like IGMP proxy, this lets devices on different VLANs do multicast communications.
+Since they are similar, use one or the other, but not both at the same time.
  \\
-**Upstream interface** - here, enter the stream source is expected to live. (Default: blank).
+**Upstream interface: **here, enter the expected stream source location.
+(Default: blank).
  \\
-**LAN0/LAN1/LAN2/LAN3** - specifies the location streaming clients are expected to be found.
+**LAN0/LAN1/LAN2/LAN3** - specifies the location streaming clients should be found.
  \\
-**Enable client statistics** -causes FreshTomato to collect statistics about Udpxy clients.
+**Enable client statistics:** causes FreshTomato to collect statistics about Udpxy clients.
  \\
-**Max clients: **the maximum number of simultaneous Udpxy clients. Since Udpxy is is a lightweight protocol, it works well for a limited number of clients. Therefore, you might want to impose a maximum limit.
+**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 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.
-However, caution is advised. IGMP Snooping can interfere with functioning of UPnP or DLNA. This can make Multicast configuration errors or deficiencies appear as UPnP issues. Enabling IGMP snooping on a router's/switch interferes with UPnP/DLNA device discovery.  Specifically, it can interfere with SSDP protocol transmissions. If IGMP snooping is incorrectly or incompletely configured (say, without an active querier or IGMP proxy), this make UPnP appear unreliable.
+However, caution is advised. IGMP Snooping can interfere with functioning of UPnP or DLNA. This can make Multicast configuration errors or deficiencies appear as UPnP issues. Enabling IGMP snooping on a router's switch interferes with UPnP/DLNA device discovery. Specifically, it can interfere with SSDP protocol transmissions. If IGMP snooping is improperly configured (say, without an active querier/IGMP proxy), it can make UPnP appear unreliable.
 A common symptom of this is a network host (say, a Smart TV) which appears after it's powered on, but then "disappears" from the network after a few minutes. To be more precise, typically 30 minutes. This is because the default setting for when IGMP group membership will expire. Please be aware of the wireless multicast forwarding setting in the the //Advanced///[[advanced-wireless|Wireless]] menu.
@@ Line 107: / Line 127: @@
  \\
-**Force IGMPv2** - IGMPv2 enhances IGMP with additional messages/behavior to optimize end-to-end client-server communication. Probably the most important one is the "Leave Group" message. When a host wants to stop listening to a multicast group address, it reports to the router that it has stopped listening. In v1, the host simply stopped listening, without informing the router.
+**Force IGMPv2: **forces IGMPv2 to be used on the network.
+IGMPv2 enhances IGMP with additional messages/behavior to optimize end-to-end client-server communication. Probably the most important one is the "Leave Group" message. When a host wants to stop listening to a multicast group address, it reports to the router that it has stopped listening. In v1, the host simply stopped listening, without informing the router.
  \\
@@ Line 117: / Line 139: @@
 MRT (Maximum Response Time) field. This new field in query messages specifies how much time hosts have to respond to the query.
-Querier election process. When two routers are on the same subnet, only one should send query messages. Having an "election" process ensures only one router, with the lowest IP address, becomes the active querier.\\   \\
+Querier election process. When two routers are on the same subnet, only one should send query messages. Having an "election" process ensures only one router, with the lowest IP address, becomes the active querier.
+ \\
+ \\ \\   \\

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