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doc:uci:firewall [2014/03/03 13:45]
ayaka more security
doc:uci:firewall [2015/06/22 22:31] (current)
M.Bastian [nf_conntrack_skip_filter]
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   * INPUT rules for a zone describe what happens to traffic trying to reach the router itself through that interface.   * INPUT rules for a zone describe what happens to traffic trying to reach the router itself through that interface.
-  * OUTPUT rules for a zone describe what happens to traffic originating from the router itself.+  * OUTPUT rules for a zone describe what happens to traffic originating from the router itself ​going through that interface.
   * FORWARD rules for a zone describe what happens to traffic coming from that zone and passing to another zone.   * FORWARD rules for a zone describe what happens to traffic coming from that zone and passing to another zone.
  
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 ^ Name ^ Type ^ Required ^ Default ^ Description ^ ^ Name ^ Type ^ Required ^ Default ^ Description ^
 | ''​name''​ | zone name | yes | //(none)// | Unique zone name | | ''​name''​ | zone name | yes | //(none)// | Unique zone name |
-| ''​network''​ | list | no | //(none)// | List of //​[[doc:​uci:​network#​interfaces|interfaces]]//​ attached to this zone. If omitted and neither extra* options, subnets or devices are given, the value of ''​name''​ is used by default |+| ''​network''​ | list | no | //(none)// | List of //​[[doc:​uci:​network#​interfaces|interfaces]]//​ attached to this zone. If omitted and neither extra* options, subnets or devices are given, the value of ''​name''​ is used by default. Use list syntax as explained in [[doc:​uci]]. ​|
 | ''​masq''​ | boolean | no | ''​0''​ | Specifies whether //​outgoing//​ zone traffic should be masqueraded - this is typically enabled on the //wan// zone | | ''​masq''​ | boolean | no | ''​0''​ | Specifies whether //​outgoing//​ zone traffic should be masqueraded - this is typically enabled on the //wan// zone |
 | ''​masq_src''​ | list of subnets | no | ''​0.0.0.0/​0''​ | Limit masquerading to the given source subnets. Negation is possible by prefixing the subnet with ''​!'';​ multiple subnets are allowed. | | ''​masq_src''​ | list of subnets | no | ''​0.0.0.0/​0''​ | Limit masquerading to the given source subnets. Negation is possible by prefixing the subnet with ''​!'';​ multiple subnets are allowed. |
 | ''​masq_dest''​ | list of subnets | no | ''​0.0.0.0/​0''​ | Limit masquerading to the given destination subnets. Negation is possible by prefixing the subnet with ''​!'';​ multiple subnets are allowed. | | ''​masq_dest''​ | list of subnets | no | ''​0.0.0.0/​0''​ | Limit masquerading to the given destination subnets. Negation is possible by prefixing the subnet with ''​!'';​ multiple subnets are allowed. |
-| ''​conntrack''​ | boolean | no | ''​1''​ if masquerading is used, ''​0''​ otherwise | Force connection tracking for this zone (see [[#note.on.connection.tracking.notrack|Note on connection tracking]]) |+| ''​conntrack''​ | boolean | no | ''​1''​ if masquerading is used, ''​0''​ otherwise | Force connection tracking for this zone (see [[#notes_on_connection_tracking|Note on connection tracking]]) |
 | ''​mtu_fix''​ | boolean | no | ''​0''​ | Enable MSS clamping for //​outgoing//​ zone traffic | | ''​mtu_fix''​ | boolean | no | ''​0''​ | Enable MSS clamping for //​outgoing//​ zone traffic |
 | ''​input''​ | string | no | ''​DROP''​ | Default policy (''​ACCEPT'',​ ''​REJECT'',​ ''​DROP''​) for //​incoming//​ zone traffic | | ''​input''​ | string | no | ''​DROP''​ | Default policy (''​ACCEPT'',​ ''​REJECT'',​ ''​DROP''​) for //​incoming//​ zone traffic |
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 | ''​log''​ | boolean | no | ''​0''​ | Create log rules for rejected and dropped traffic in this zone. | | ''​log''​ | boolean | no | ''​0''​ | Create log rules for rejected and dropped traffic in this zone. |
 | ''​log_limit''​ | string | no | ''​10/​minute''​ | Limits the amount of log messages per interval. | | ''​log_limit''​ | string | no | ''​10/​minute''​ | Limits the amount of log messages per interval. |
-| ''​device''​ | list | no | //(none)// | List of raw network device names attached to this zone, e.g. ''​ppp+''​ to match any PPP interface. \\ :!: Only supported by the Firewall v2, version 58 and above | +| ''​device''​ | list | no | //(none)// | List of raw network device names attached to this zone, e.g. ''​ppp+''​ to match any PPP interface. \\ :!: Only supported by the Firewall v2, version 58 and above ; not supported by 12.09 default installation ​
-| ''​subnet''​ | list | no | //(none)// | List of IP subnets attached to this zone. \\ :!: Only supported by the Firewall v2, version 58 and above | +| ''​subnet''​ | list | no | //(none)// | List of IP subnets attached to this zone. \\ :!: Only supported by the Firewall v2, version 58 and above, not supported by 12.09 default installation ​
-| ''​extra''​ | string | no | //(none)// | Extra arguments passed directly to iptables. Note that these options are passed to both source and destination classification rules, therfore direction-specific options like ''​--dport''​ should not be used here - in this case the ''​extra_src''​ and ''​extra_dest''​ options should be used instead. \\ :!: Only supported by the Firewall v2, version 58 and above | +| ''​extra''​ | string | no | //(none)// | Extra arguments passed directly to iptables. Note that these options are passed to both source and destination classification rules, therfore direction-specific options like ''​--dport''​ should not be used here - in this case the ''​extra_src''​ and ''​extra_dest''​ options should be used instead. \\ :!: Only supported by the Firewall v2, version 58 and above, not supported by 12.09 default installation ​
-| ''​extra_src''​ | string | no | //Value of ''​extra''//​ | Extra arguments passed directly to iptables for source classification rules. \\ :!: Only supported by the Firewall v2, version 58 and above | +| ''​extra_src''​ | string | no | //Value of ''​extra''//​ | Extra arguments passed directly to iptables for source classification rules. \\ :!: Only supported by the Firewall v2, version 58 and above, not supported by 12.09 default installation ​
-| ''​extra_dest''​ | string | no | //Value of ''​extra''//​ | Extra arguments passed directly to iptables for destination classification rules. \\ :!: Only supported by the Firewall v2, version 58 and above |+| ''​extra_dest''​ | string | no | //Value of ''​extra''//​ | Extra arguments passed directly to iptables for destination classification rules. \\ :!: Only supported by the Firewall v2, version 58 and above, not supported by 12.09 default installation ​|
  
 ==== Forwardings ==== ==== Forwardings ====
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 //Redirects are also commonly known as "port forwarding",​ and "​virtual servers"​.//​ //Redirects are also commonly known as "port forwarding",​ and "​virtual servers"​.//​
 +
 +Port ranges are specified as ''​start:​stop'',​ for instance ''​6666:​6670''​. ​ This is similar to the iptables syntax.
  
 The options below are valid for //​redirects//:​ The options below are valid for //​redirects//:​
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 | ''​reflection''​ | boolean | no | ''​1''​ | Activate NAT reflection for this redirect - applicable to ''​DNAT''​ targets. | | ''​reflection''​ | boolean | no | ''​1''​ | Activate NAT reflection for this redirect - applicable to ''​DNAT''​ targets. |
 | ''​reflection_src''​ | string | no | ''​internal''​ | The source address to use for NAT-reflected packets if ''​reflection''​ is ''​1''​. This can be ''​internal''​ or ''​external'',​ specifying which interface’s address to use. Applicable to ''​DNAT''​ targets. | | ''​reflection_src''​ | string | no | ''​internal''​ | The source address to use for NAT-reflected packets if ''​reflection''​ is ''​1''​. This can be ''​internal''​ or ''​external'',​ specifying which interface’s address to use. Applicable to ''​DNAT''​ targets. |
-| ''​limit''​ | string | no | //(none)// | Maximum average matching rate; specified as a number, with an optional ''/​second'',​ ''/​minute'',​ ''/​hour''​ or ''/​day''​ suffix. ​Example: ''​3/​hour''​. |+| ''​limit''​ | string | no | //(none)// | Maximum average matching rate; specified as a number, with an optional ''/​second'',​ ''/​minute'',​ ''/​hour''​ or ''/​day''​ suffix. ​Examples: ''​3/​second'',​ ''​3/​sec''​ or ''​3/​s''​. |
 | ''​limit_burst''​ | integer | no | ''​5''​ | Maximum initial number of packets to match, allowing a short-term average above ''​limit''​ | | ''​limit_burst''​ | integer | no | ''​5''​ | Maximum initial number of packets to match, allowing a short-term average above ''​limit''​ |
 | ''​extra''​ | string | no | //(none)// | Extra arguments to pass to iptables. Useful mainly to specify additional match options, such as ''​-m policy %%--%%dir in''​ for IPsec. | | ''​extra''​ | string | no | //(none)// | Extra arguments to pass to iptables. Useful mainly to specify additional match options, such as ''​-m policy %%--%%dir in''​ for IPsec. |
 +| ''​enabled''​ | string | no | ''​1''​ or ''​yes''​ | Enable the redirect rule or not. |
  
 :!: On Attitude Adjustment, for NAT reflection to work, you **must** specify ''​option dest lan''​ in the ''​redirect''​ section (even though we're using a ''​DNAT''​ target). :!: On Attitude Adjustment, for NAT reflection to work, you **must** specify ''​option dest lan''​ in the ''​redirect''​ section (even though we're using a ''​DNAT''​ target).
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   * If only ''​dest''​ is given, the rule matches //​outgoing//​ traffic   * If only ''​dest''​ is given, the rule matches //​outgoing//​ traffic
   * If neither ''​src''​ nor ''​dest''​ are given, the rule defaults to an //​outgoing//​ traffic rule   * If neither ''​src''​ nor ''​dest''​ are given, the rule defaults to an //​outgoing//​ traffic rule
 +
 +Port ranges are specified as ''​start:​stop'',​ for instance ''​6666:​6670''​. ​ This is similar to the iptables syntax.
  
 Valid options for this section are: Valid options for this section are:
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 | ''​set_xmark''​ | ::: | ::: | ::: | Zeroes out the bits given by mask and XORs value into the packet mark. If mask is omitted, 0xFFFFFFFF is assumed | | ''​set_xmark''​ | ::: | ::: | ::: | Zeroes out the bits given by mask and XORs value into the packet mark. If mask is omitted, 0xFFFFFFFF is assumed |
 | ''​family''​ | string | no | ''​any''​ | Protocol family (''​ipv4'',​ ''​ipv6''​ or ''​any''​) to generate iptables rules for. | | ''​family''​ | string | no | ''​any''​ | Protocol family (''​ipv4'',​ ''​ipv6''​ or ''​any''​) to generate iptables rules for. |
-| ''​limit''​ | string | no | //(none)// | Maximum average matching rate; specified as a number, with an optional ''/​second'',​ ''/​minute'',​ ''/​hour''​ or ''/​day''​ suffix. ​Example: ''​3/​hour''​. |+| ''​limit''​ | string | no | //(none)// | Maximum average matching rate; specified as a number, with an optional ''/​second'',​ ''/​minute'',​ ''/​hour''​ or ''/​day''​ suffix. ​Examples: ''​3/​minute'',​ ''​3/​min''​ or ''​3/​m''​. |
 | ''​limit_burst''​ | integer | no | ''​5''​ | Maximum initial number of packets to match, allowing a short-term average above ''​limit''​ | | ''​limit_burst''​ | integer | no | ''​5''​ | Maximum initial number of packets to match, allowing a short-term average above ''​limit''​ |
 | ''​extra''​ | string | no | //(none)// | Extra arguments to pass to iptables. Useful mainly to specify additional match options, such as ''​-m policy %%--%%dir in''​ for IPsec. | | ''​extra''​ | string | no | //(none)// | Extra arguments to pass to iptables. Useful mainly to specify additional match options, such as ''​-m policy %%--%%dir in''​ for IPsec. |
 +| ''​enabled''​ | boolean | no | yes | Enable or disable rule. |
  
 ==== Includes ==== ==== Includes ====
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 This example enables machines on the internet to use SSH to access your router. This example enables machines on the internet to use SSH to access your router.
-==== Forwarding ports (Destination NAT/DNAT) ====+==== Port forwarding for IPv4 (Destination NAT/DNAT) ====
  
 This example forwards http (but not HTTPS) traffic to the webserver running on 192.168.1.10:​ This example forwards http (but not HTTPS) traffic to the webserver running on 192.168.1.10:​
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 <​code>​ <​code>​
-config ​'redirect'​ +config redirect 
-        option 'name' 'ssh+        option src       wan 
-        option '​src'​ 'wan+        option src_dport 5555 
-        option '​proto'​ 'tcpudp+        option proto     tcp 
-        option 'src_dport' '5555+        option dest      lan 
-        option 'dest_ip' '​192.168.1.100+        option dest_ip ​  ​192.168.1.100 
-        option ​'dest_port'​ '​22'​ +        option dest_port 22 
-        option 'target' 'DNAT+</​code>​ 
-        option 'dest' '​lan'​+ 
 +==== DNAT/SNAT redirects and forwarding combination ==== 
 +Given a couple of redirect (DNAT and SNAT, like to redirect 
 +the traffic from an host to and from a specific ip address) such as: 
 +<​file>​ 
 +config redirect 
 +        option name     '​icmp DNAT
 +        option ​src      ​'wan' 
 +        option src_dip ​  '1.2.3.4
 +        option ​proto    ​'icmp'​ 
 +        option dest     '​dmz'​ 
 +        option dest_ip ​ '​192.168.1.79'​ 
 +        option target ​  '​DNAT'​ 
 + 
 +config redirect 
 +        option name     '​icmp SNAT'​ 
 +        option ​src      'dmz' 
 +        option src_ip ​  '​192.168.1.79
 +        option ​src_dip  ​'1.2.3.4'​ 
 +        option ​proto    'icmp' 
 +        option dest     '​wan
 +        option ​target ​  'SNAT' 
 +</​file>​ 
 + 
 +Someone could ask "//Ok, the packet source or destination is changed, 
 +but still has to be forwarded towards the right network interface to reach the 
 +endpoint//"​. So the administrator of openwrt could wonder of adding 
 +additional forwarding rules but no, it is not needed. The forwarding 
 +rules are added by the firewall appliance itself. 
 + 
 +The same applies to the masquerading,​ the rules are applied //​before//​ 
 +the global masquerading (if a masquerading is set), therefore they will 
 +not be overridden (at least the SNAT) by the masquerading mechanism. 
 +==== Masquerading on lan ==== 
 +Suppose that you have two routers, connected each other through the  
 +lan zone (both have static ip and dhcp disabled),  
 +and only one of them is connected to the internet through the wan zone.  
 +In other words the situation is: 
 +<​code>​ 
 +internet <​---->​ wan (172.22.13.228) | router 1 | lan (192.168.1.254) <​---->​ lan (192.168.1.1) | router 2 | wan (no connection) 
 +</​code>​ 
 + 
 +If both routers have the default openwrt configuration  
 +(with the exceptions mentioned above), then a device on the lan side of the 
 +router 1 can communicate through the internet if it has the router 1 as 
 +gateway, this because the packet flow between devices is managed by routing. 
 +In our case the router 2 has no proper setup in terms of gateway, 
 +as the default openwrt configuration expects that a wan connection 
 +on the router 2 is provided. 
 + 
 +Anyway suppose that on the router 1 we have the following rule: 
 +<​code>​ 
 +config redirect 
 +        option target ​'DNAT
 +        option ​src 'wan' 
 +        option dest '​lan'​ 
 +        option proto '​tcp'​ 
 +        option src_dip '​172.22.13.228'​ 
 +        option src_dport '​2023'​ 
 +        option dest_ip ​'​192.168.1.1
 +        option dest_port '23' 
 +        option name '​Telnet to new Router'​  
 +</​code>​ 
 +This rule is redirecting the tcp packets on the port 2023 with destination the wan ip of the router 1  
 +(172.22.13.228) towards the lan ip of the router 2.  
 +The router 2 cannot reply to those packets because we didn't adjust its routing table, 
 +that is we didn't specify that the gateway to reply to "​wan"​ sources is the router 1. 
 +Indeed those redirected packets will have an source ip external from the (default) "​lan"​ zone 192.168.1.0/​24. 
 + 
 +We can solve this activating the masquerading on the "​lan"​ zone on the router 1, in this way. 
 +<​code>​ 
 +config zone 
 +        option ​name 'lan' 
 +        option network ​'lan
 +        option ​input 'ACCEPT' 
 +        option output ​'ACCEPT'​ 
 +        option forward '​REJECT'​ 
 +        option masq '​1'​ 
 +</​code>​ 
 +This setup will provide the following effect (that is the effect intended by the masquerading):​ if a packet, belonging to a certain [[wp>​Virtual_circuit|connection]],​ is coming into the lan zone with a source ip belonging to another zone, keep track of the connection, taking note of the source ip of that connection, and modify the source ip with the ip of the router in the lan zone (that is: source_ip from a.b.c.d to 192.168.1.254). \\  
 +Then deliver the packet to the intended destination (that is, 192.168.1.1,​ the router2). Afterwards, if a packet from 192.168.1.1 is coming back towards 192.168.1.254,​ belonging to the connection tracked before, changed back the destination ip (here is the second effect of the masquerading) with the source ip memorized before (that is, dest_ip from 192.168.1.254 to a.b.c.d ). In this way, for the point of view of the router 2, the router 2 just communicate with a device with an ip belonging to its "​lan"​ zone , and therefore the default routing is working without problem. 
 + 
 +At least one side effect of this setup is that every device in the lan zone of the router 1 cannot see any "​wan"​ ip, and this could be not wanted for several reasons (one of which: if you setup a proper gateway, there is no need for this masquerading). But this was just a "​special case" to expose in brief how the masquerading works and how it could be applied to zones that usually don't use it. An improvement of "​masquerading only for a specific device in the zone" could be the following:​ 
 +<​code>​ 
 +config zone 
 +        option name '​lan'​ 
 +        option network '​lan'​ 
 +        option input '​ACCEPT'​ 
 +        option output '​ACCEPT'​ 
 +        option forward '​REJECT'​ 
 +        option masq '​1'​ 
 +        option masq_dest '​192.168.1.1/​32'​ 
 +</​code>​ 
 +This provide the masquerading feature only if the packets are send towards the destination 192.168.1.1/​32 (this subnet should belong to the lan zone). 
 +==== Port accept for IPv6 ==== 
 + 
 +To open port 80 so that a local webserver at ''​2001:​db8:​42::​1337''​ can be reached from the Internet: 
 + 
 +<​code>​ 
 +config rule 
 +        option src       wan 
 +        option proto     tcp 
 +        option dest      lan 
 +        option dest_ip ​  ​2001:​db8:​42::​1337 
 +        option dest_port 80 
 +        option family ​   ipv6 
 +        option target ​   ACCEPT 
 +</​code>​ 
 + 
 +To open SSH access to all IPv6 hosts in the local network: 
 + 
 +<​code>​ 
 +config rule 
 +        option src       wan 
 +        option proto     tcp 
 +        option dest      lan 
 +        option dest_port 22 
 +        option family ​   ipv6 
 +        option target ​   ACCEPT 
 +</​code>​ 
 + 
 +To open all TCP/UDP port between 1024 and 65535 towards the local IPv6 network: 
 + 
 +<​code>​ 
 +config rule 
 +        option src       wan 
 +        option proto     ​tcpudp 
 +        option dest      lan 
 +        option dest_port 1024:​65535 
 +        option family ​   ipv6 
 +        option target ​   ACCEPT
 </​code>​ </​code>​
  
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 ==== Block access to the Internet for specific IP on certain times  ==== ==== Block access to the Internet for specific IP on certain times  ====
  
-The following rule blocks all connection attempts to the internet from 192.168.1.27 on weekdays between 21:00pm and 09:00am.\\+The following rule blocks all connection attempts to the internet from 192.168.1.27 on weekdays between 21:00pm and 09:​00am ​(times are specified in UTC unless the --kerneltz switch is used).\\
 :!: The package ''​iptables-mod-ipopt''​ must be installed to provide ''​xt_time''​. :!: The package ''​iptables-mod-ipopt''​ must be installed to provide ''​xt_time''​.
  
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 </​code>​ </​code>​
  
 +==== Zone declaration for semi non-UCI interfaces, manually listed in the network config, and forwardings ====
 +Scenario: having one or more vpn tunnels using openvpn,
 +with the need of defining a zone to forward the traffic between the
 +vpn interfaces and the lan.
 +
 +First list the interfaces in **/​etc/​config/​network**, ​
 +for example in the following way: (be careful on the limits of interface naming in terms of name length, [[doc/​uci/​network|read more]])
 +<​code>​
 +config interface '​tun0'​
 + option ifname '​tun0'​
 + option proto '​none'​
 +
 +config interface '​tun1'​
 +        option ifname '​tun1'​
 +        option proto '​none'​
 +</​code>​
 +
 +Then create the zone in **/​etc/​config/​firewall**,​ for example one zone for all the vpn interfaces.
 +<​code>​
 +config zone
 +        option name             ​vpn_tunnel
 +        list   ​network ​         '​tun0'​
 + list   ​network ​         '​tun1'​
 +        option input            ACCEPT
 +          #the traffic towards the router from the interface will be accepted
 +          #(as for the lan communications)
 +        option output ​          ​ACCEPT
 +          #the traffic from the router to the interface will be accepted
 +        option forward ​         REJECT
 +          #traffic from this zone to other zones is normally rejected
 +</​code>​
 +
 +Then we want to communicate with the "​lan"​ zone, therefore we need forwardings in both ways
 +(from lan to wan and viceversa)
 +<​code>​
 +config forwarding
 +        option src              lan
 +        option dest             ​vpn_tunnel
 +        #if a packet from lan wants to go to the vpn_tunnel zone
 +        #let it pass
 +
 +config forwarding
 +        option src              vpn_tunnel
 +        option dest             lan
 +        #if a packet from vpn_tunnel wants to go to the lan zone
 +        #let it pass
 +</​code>​
 +This will create a lot of "​automatic"​ iptables rules (because automatic scripting is not
 +as efficient as raw iptable commands in /​etc/​firewall.user) ​
 +but those rules will be more clear in the luci webinterface and also more readable for
 +less expert users.
 +
 +In general remember that forwardings are relying how routing rules are defined, and afterwards which zones are
 +defined on which interfaces.
 ==== Zone declaration for non-UCI interfaces ==== ==== Zone declaration for non-UCI interfaces ====
  
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-===== Note on connection tracking ​(NOTRACK) ​=====+===== Notes on connection tracking ===== 
 + 
 +==== NOTRACK ​====
  
 By default, the firewall will disable connection tracking for a zone if no masquerading is enabled. This is achieved by generating //NOTRACK// firewall rules matching all traffic passing via interfaces referenced by the firewall zone. The purpose of //NOTRACK// is to speed up routing and save memory by circumventing resource intensive connection tracking in cases where it is not needed. You can check if connection tracking is disabled by issuing ''​iptables -t raw -vnL'',​ it will list all rules, check for //NOTRACK// target. By default, the firewall will disable connection tracking for a zone if no masquerading is enabled. This is achieved by generating //NOTRACK// firewall rules matching all traffic passing via interfaces referenced by the firewall zone. The purpose of //NOTRACK// is to speed up routing and save memory by circumventing resource intensive connection tracking in cases where it is not needed. You can check if connection tracking is disabled by issuing ''​iptables -t raw -vnL'',​ it will list all rules, check for //NOTRACK// target.
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 If connection tracking is required, for example by custom rules in ''/​etc/​firewall.user'',​ the ''​conntrack''​ option must be enabled in the corresponding zone to disable //​NOTRACK//​. It should appear as ''​option '​conntrack'​ '​1'​ ''​ in the right zone in ''/​etc/​config/​firewall''​. If connection tracking is required, for example by custom rules in ''/​etc/​firewall.user'',​ the ''​conntrack''​ option must be enabled in the corresponding zone to disable //​NOTRACK//​. It should appear as ''​option '​conntrack'​ '​1'​ ''​ in the right zone in ''/​etc/​config/​firewall''​.
 For further information see http://​security.maruhn.com/​iptables-tutorial/​x4772.html . For further information see http://​security.maruhn.com/​iptables-tutorial/​x4772.html .
 +
 +==== nf_conntrack_skip_filter ====
 +
 +:!: Only available in Barrier Breaker. **''​Revoked in Chaos Calmer RC1 and onwards''​** due to various problems.
 +
 +From [[https://​dev.openwrt.org/​changeset/​42048/​trunk/​package|r42048]] to [[https://​dev.openwrt.org/​changeset/​44873|r44873]],​ there was a new setting activated by default which causes the packets with the established state, completely bypass iptables filter table. This is to [[https://​dev.openwrt.org/​ticket/​17690#​comment:​6|help with network performance]] and unless you need all packets to be counted by iptables filter or have some specific rules which would apply to already established connections,​ you should leave it active. ​
 +
 +This behavior can be disabled by editing /​etc/​sysctl.conf :
 +  net.netfilter.nf_conntrack_skip_filter=0
 +and then activating the new setting:
 +  sysctl -p
 +
 +or be temporarily turned off untill the next reboot by issuing :
 +  sysctl -w net.netfilter.nf_conntrack_skip_filter=0
  
 ===== How to delete a rule ===== ===== How to delete a rule =====
Line 742: Line 948:
 | :::    | ''​postrouting_//​name//​_rule''​ | user     | Per-zone container chains for custom user postrouting rules (firewall.user) | | :::    | ''​postrouting_//​name//​_rule''​ | user     | Per-zone container chains for custom user postrouting rules (firewall.user) |
  
 +===== Open questions =====
 +==== '​enabled'​ option ====
 +Could it be that the enable option is available for every section
 +of the firewall file?
doc/uci/firewall.1393850717.txt.bz2 · Last modified: 2014/03/03 13:45 by ayaka