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advanced-firewall [2022/01/21 02:59] hogwildadvanced-firewall [2023/05/28 05:39] (current) – [Multicast] -condense, list/explain additional features of new IGMPv2 messages hogwild
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-===== Firewall =====+====== Firewall ======
  
-The Firewall page allows you to configure options to protect/facilitate certain network communications.\\  \\+The Firewall page allows you to configure options to protect or facilitate various types of network communications. 
 + 
 + 
 +===== Firewall =====
  
 {{:pasted:20220118-182859.png}} \\ {{:pasted:20220118-182859.png}} \\
-\\ 
-**WAN interfaces respond to ping and traceroute** - If enabled, allows your device to reply to certain ICMP/UDP packets from Internet hosts so that //ping //and //traceroute //will work from the Internet. 
  
-**Limit communication to **- Specifies the maximum number of requests per second to which the Firewall will reply. Setting a limit number is recommended to prevent DDoS attacks.\\+ \\ **WAN interfaces respond to ping and traceroute:  **If enabled, this allows your device to reply to ICMP ping and traceroute request packets from Internet hosts. This is necessary for //ping //and //traceroute to //work from the Internet. 
 + 
 +**Limit communication to:  **This specifies the maximum number of requests per second to which the Firewall will reply. Setting a limit number is recommended to prevent DDoS attacks.\\   \\   \\ {{:pasted:20220118-183317.png}}\\ 
  \\  \\
-{{:pasted:20220118-183317.png}}\\ 
  
-**Enable TCP SYN cookies** Enabling this protects the router from SYN Flood attacks via the well-known "SYN cookies" technique. This function encodes information from the SYN packet into the response (SYN/ACK). Despite being a standard techniqueenabling this will create some secondary limitations that may not be handled well by some old TCP/IP stacks.+**Enable TCP SYN cookies:  **Enabling this uses the "SYN cookies" technique to protect the router from SYN Flood attacks. This function encodes information from the SYN packet into the (SYN/ACK) responseThis is a standard method for preventing SYN floods. Howeverit has certain limitations which may cause issues with some old TCP/IP stacks.
  
-**Enable DCSP Fix** - This enables a workaround for a well-known issue related to DSCP (packet marking) when connected to the Comcast ISP.+**Enable DCSP Fix:  **Checking this enables a workaround for packet marking, a well-known issue related to DSCP when connected to Comcast.
  
-**IPv6 IPSec Passthrough** - FIXME\\ \\+**Allow DHCP Spoofing: **
  
- \\+**Smart MTU black hole detection:**
  
-{{:pasted:20220118-184523.png}}\\ 
  
-**NAT loopback** - also known as "Hairpinning", this technique allows LAN devices to access another LAN device via the WAN interface of your routerThis is common practice, for example, when connecting to the DDNS domain of your router from the LAN (for administration purposes)This legacy setting is rarely, if ever needed nowadays. It also can create a bottleneck on fast connections.+===== NAT ===== 
 + 
 +**NAT loopback:** This technique allows LAN devices to access each other via the router'WAN interface. Also known as "Hairpinning"this is commonly used when connecting to the DDNS domain of your router from the LAN. These days, this legacy setting is almost never needed. It also can create speed bottlenecks.
  
   * All   * All
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   * Disabled   * Disabled
  
-**NAT target** - Defines the way NAT is implemented for the sake of Hairpinning. Masquerade is the default, however this involves an additional lookup ad the mapping of done towards an interface. SNAT is minimally minutely faster as the NAT mapping points directly to the destination IP and so it bypasses the lookup stage.+\\ 
 + 
 +{{::advanced-firewall-nat.jpg?454}} \\ \\ 
 + 
 +**NAT target** - This defines the way NAT is implemented for use during loopback. Masquerade is the default, but involves an additional lookupad the mapping of done towards an interface. SNAT is minutely fasteras the NAT mapping points directly to the destination IP and so it bypasses the lookup stage. However, SNAT is less reliable than Masquerade.
  
  \\  \\
  
-Multicast\\ {{:pasted:20220118-185509.png}}\\  \\ 
  
-**Enable IGMP proxy** - Runs the IGMP (Internet Group Management Protocol) service on the router.+===== Multicast =====
  
-**LAN0/LAN1/LAN2/LAN3** Specifies which bridges will be subscribed to partecipate in IGMP using the router as a proxy between the LANs selected. Essentially, this allows IGMP to work between VLANs.+ \\ \\ {{:pasted:20220118-185509.png}}\\  \\
  
-**Enable quick leave** - This is a feature of IGMP v2. This allows the router to stop the streaming of a multicast to an IP address as soon as that end device sends the quick leave IGMP packet.+**Enable IGMP proxy** - Checking this enables the IGMP (Internet Group Management Protocol) service.
  
-**Custom Configuration** - This option allows you to set up advanced parameters for the IGMP proxy daemon. Please consult the official IGMP documentation before finalizing these settings.\\+LAN0 - LAN3 Specifies which bridges will participate in IGMP, with the router acting as a proxy between selected LANs. This allows IGMP to work between VLANs. 
 + 
 +  * LAN0 - Checking this means the LAN0 bridge will participate in IGMP proxy. 
 +  * LAN1 - Checking this means the LAN1 bridge will participate in IGMP proxy. 
 +  * LAN2 - Checking this means the LAN2 bridge will participate in IGMP proxy. 
 +  * LAN3 - Checking this means the LAN3 bridge will participate in IGMP proxy. 
 + 
 + \\ 
 + 
 +**Enable quick leave** - This is a feature of IGMP v2 and later. Enabling this allows the router to stop streaming multicast to an IP address as soon as that device sends a "quick leave" IGMP packet. 
 + 
 +**Custom Configuration** - This option allows you to set advanced parameters for the IGMP proxy daemon. Consult official IGMP documentation before using this.\\   \\
  
  \\ {{:pasted:20220118-190050.png}}\\  \\  \\ {{:pasted:20220118-190050.png}}\\  \\
  
-**Enable Udpxy** - Like IGMP proxy, Udpxy allows multicast communications between senders and receivers in different VLANs. Since their behavior is almost identicalit is recommended you use either Udpxy or IGMP proxy, but not both at the same time.+**Enable Udpxy** - Like IGMP proxy, Udpxy allows multicast communications between devices on different VLANs. Since their behavior is very similar, you are advised to use either Udpxy or IGMP proxy, but not both at once. 
 + 
 +**Upstream interface** - Here, enter the stream source is expected to live. (Default: blank). 
 + 
 +**LAN0/LAN1/LAN2/LAN3** - This specifies the location the streaming clients are expected to be found. 
 + 
 +**Enable client statistics** - Enabling this causes FreshTomato to collect statistics about Udpxy clients. 
 + 
 +**Max clients - ** This represents the maximum number of simultaneous Udpxy clients. Udpxy is is a lightweight protocol, and only works well for a limited number of clients. For this reason, you might want to impose a maximum limit. 
 + 
 +**Udpxy port**- This specifies the port on which you can recive Udpxy information from your router.\\  \\   \\  {{:pasted:20220118-190844.png}}\\  \\
  
-**Upstream interface** - Defines where the stream source is expected to live(Default: blank).+**Efficient Multicast Forwarding (IGMP Snooping) -** IGMP snooping makes the router's switch facilitate discovery of Multicast IGMP clientsThis will help to send multicast traffic only towards ports with at least one multicast subscriber, reducing overall multicast traffic.
  
-**LAN0/LAN1/LAN2/LAN3** - This is where the stream clients are expected to live.+However, caution is advised. IGMP Snooping can interfere with proper 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 will interfere 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.
  
-**Enable client statistics** - Enabling this causes FreshTomato to collect statistical information about Udpxy clients.+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, often this period is 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.
  
-**Max clients -** Considering this is a lightwave protocol it works well for limited number of clientsyou might want to impose a maximum number.Specifies the maximum number of simultaneous Udpxy clients.+**Force IGMPv2** - IGMPv2 enhances IGMP with additional messages/behavior to optimize end-to-end client-server communication. Perhaps the most important of these additional messages is the "Leave Group" message. When host no longer wants to listen to multicast group addressit will report to the router that it has stopped listeningIn v1, the host simply stopped listening, without informing the router.
  
-**Udpxy port**- This is where you can consult the Udpxy information on your router.\\  \\+Other features of IGMPv2 include:
  
-{{:pasted:20220118-190844.png}}\\+Group specific membership query. The router can now send a membership query for a specific group address. When the router receives a leave group message, it will use this query to check if there are still any hosts interested in receiving the multicast traffic.
  
-**Efficient Multicast Forwarding (IGMP Snooping-** IGMP snooping is a way to have the switch (router) facilitating the discovery of multicast (IGMP) clients. Beware that enabling IGMP snooping might interfere with some multicast-based applications/protocols. This issue is well-known, for example when using uPnP (Universal Plug 'n Play).+MRT (Maximum Response Timefield. This new field in query messages specifies how much time hosts have to respond to the query.
  
-**Force IGMPv2** - IGMPv2 enhances the IGMP communication supporting additional messages/behavior to optimise the end-to-end communication between client and serverPossibly the most important being the "Group Leavemessage which is lacking instead in IGMP v1.\\+Querier election process. When two routers are connected to the same subnet, only one of them should send query messagesHaving an "electionprocess ensures only one router, the router with the lowest IP address, becomes the active querier.\\   \\
  
  
advanced-firewall.1642733979.txt.gz · Last modified: 2022/01/21 02:59 by hogwild