Provided by: shorewall_5.2.3.4-1_all bug


       hosts - Shorewall file




       This file is used to define zones in terms of subnets and/or individual IP addresses. Most
       simple setups don't need to (should not) place anything in this file.

       The order of entries in this file is not significant in determining zone composition.
       Rather, the order that the zones are declared in shorewall-zones[1](5) determines the
       order in which the records in this file are interpreted.

           The only time that you need this file is when you have more than one zone connected
           through a single interface.

           If you have an entry for a zone and interface in shorewall-interfaces[2](5) then do
           not include any entries in this file for that same (zone, interface) pair.

       The columns in the file are as follows.

       ZONE - zone-name
           The name of a zone declared in shorewall-zones[1](5). You may not list the firewall
           zone in this column.

       HOST(S) - interface:{[{address-or-range[,address-or-range]...|+ipset|dynamic}[exclusion]
           The name of an interface defined in the shorewall-interfaces[2](5) file followed by a
           colon (":") and a comma-separated list whose elements are either:

            1. The IP address of a host.

            2. A network in CIDR format.

            3. An IP address range of the form low.address-high.address. Your kernel and iptables
               must have iprange match support.

            4. The name of an ipset.

            5. The word dynamic which makes the zone dynamic in that you can use the shorewall
               add and shorewall delete commands to change to composition of the zone.

           You may also exclude certain hosts through use of an exclusion (see

       OPTIONS (Optional) - [option[,option]...]
           A comma-separated list of options from the following list. The order in which you list
           the options is not significant but the list must have no embedded white-space.

               Check packets arriving on this port against the shorewall-blacklist[4](5) file.

               Used when you want to include limited broadcasts (destination IP address
      from the firewall to this zone. Only necessary when:

                1. The network specified in the HOST(S) column does not include

                2. The zone does not have an entry for this interface in

               Normally used with the Multi-cast IP address range ( Specifies that
               traffic will be sent to the specified net(s) but that no traffic will be received
               from the net(s).

               The zone is accessed via a kernel 2.6 ipsec SA. Note that if the zone named in the
               ZONE column is specified as an IPSEC zone in the shorewall-zones[1](5) file then
               you do NOT need to specify the 'ipsec' option here.

               Connection requests from these hosts are compared against the contents of
               shorewall-maclist[5](5). If this option is specified, the interface must be an
               Ethernet NIC or equivalent and must be up before Shorewall is started.

               Added in Shorewall 4.5.2. When present, causes the TCP mss for new connections
               to/from the hosts given in the HOST(S) column to be clamped at the specified mss.

               This option only makes sense for ports on a bridge.

               Filter packets for smurfs (packets with a broadcast address as the source).

               Smurfs will be optionally logged based on the setting of SMURF_LOG_LEVEL in
               shorewall.conf[6](5). After logging, the packets are dropped.

               Shorewall should set up the infrastructure to pass packets from this/these
               address(es) back to themselves. This is necessary if hosts in this group use the
               services of a transparent proxy that is a member of the group or if DNAT is used
               to send requests originating from this group to a server in the group.

               Packets arriving from these hosts are checked for certain illegal combinations of
               TCP flags. Packets found to have such a combination of flags are handled according
               to the setting of TCP_FLAGS_DISPOSITION after having been logged according to the
               setting of TCP_FLAGS_LOG_LEVEL.


       Example 1
           The firewall runs a PPTP server which creates a ppp interface for each remote client.
           The clients are assigned IP addresses in the network and in a zone
           named 'vpn'.

               #ZONE       HOST(S)               OPTIONS
               vpn         ppp+:







        1. shorewall-zones

        2. shorewall-interfaces

        3. shorewall-exclusion

        4. shorewall-blacklist

        5. shorewall-maclist

        6. shorewall.conf