Ubuntu Manpage: policy - shorewall6 policy file

NAME

       policy - shorewall6 policy file

SYNOPSIS

       /etc/shorewall6/policy

DESCRIPTION

This file defines the high-level policy for connections between zones defined in
shorewall6-zones[1](5).

Important
The order of entries in this file is important

This file determines what to do with a new connection request if we don't get a match
from the /etc/shorewall6/rules file . For each source/destination pair, the file is
processed in order until a match is found ("all" will match any client or server).

Important
Intra-zone policies are pre-defined

For $FW and for all of the zones defined in /etc/shorewall6/zones, the POLICY for
connections from the zone to itself is ACCEPT (with no logging or TCP connection rate
limiting but may be overridden by an entry in this file. The overriding entry must be
explicit (specifying the zone name on both SOURCE and DEST) or it must use "all+ or it
must use "all+" (Shorewall 4.5.17 or later).

Similarly, if you have IMPLICIT_CONTINUE=Yes in shorewall6.conf, then the implicit
policy to/from any sub-zone is CONTINUE. These implicit CONTINUE policies may also be
overridden by an explicit entry in this file.

The columns in the file are as follows (where the column name is followed by a different
name in parentheses, the different name is used in the alternate specification syntax).

SOURCE - zone|$FW|all|all+
Source zone. Must be the name of a zone defined in shorewall-zones[2](5), $FW, "all"
or "all+".

Support for "all+" was added in Shorewall 4.5.17. "all" does not override the implicit
intra-zone ACCEPT policy while "all+" does.

DEST - zone|$FW|all|all+
Destination zone. Must be the name of a zone defined in shorewall-zones[2](5), $FW,
"all" or "all+". If the DEST is a bport zone, then the SOURCE must be "all", "all+",
another bport zone associated with the same bridge, or it must be an ipv4 zone that is
associated with only the same bridge.

Support for "all+" was added in Shorewall 4.5.17. "all" does not override the implicit
intra-zone ACCEPT policy while "all+" does.

POLICY -
{ACCEPT|DROP|REJECT|CONTINUE|QUEUE|NFQUEUE[(queuenumber)]|NONE}[:{default-action-or-macro|None}]
Policy if no match from the rules file is found.

If the policy is neither CONTINUE nor NONE then the policy may be followed by ":" and
one of the following:

1. The word "None" or "none". This causes any default action defined in
shorewall.conf[3](5) to be omitted for this policy.

2. The name of an action. The action will be invoked before the policy is enforced.

Actions can have parameters specified.

Beginning with Shorewall 4.5.10, the action name can be followed optionally by a colon
and a log level. The level will be applied to each rule in the action or body that
does not already have a log level.

Possible actions are:

ACCEPT
Accept the connection.

DROP
Ignore the connection request.

REJECT
For TCP, send RST. For all other, send an "unreachable" ICMP.

QUEUE
Queue the request for a user-space application such as Snort-inline.

NFQUEUE
Queue the request for a user-space application using the nfnetlink_queue
mechanism. If a queuenumber is not given, queue zero (0) is assumed.

CONTINUE
Pass the connection request past any other rules that it might also match (where
the source or destination zone in those rules is a superset of the SOURCE or DEST
in this policy). See shorewall6-nesting[4](5) for additional information.

NONE
Assume that there will never be any packets from this SOURCE to this DEST.
shorewall6 will not create any infrastructure to handle such packets and you may
not have any rules with this SOURCE and DEST in the /etc/shorewall6/rules file. If
such a packet is received, the result is undefined. NONE may not be used if the
SOURCE or DEST columns contain the firewall zone ($FW) or "all".

LOG LEVEL (loglevel) - [log-level|NFLOG]
Optional - if supplied, each connection handled under the default POLICY is logged at
that level. If not supplied, no log message is generated. See syslog.conf(5) for a
description of log levels.

You may also specify NFLOG (must be in upper case). This will log to the NFLOG target
and will send to a separate log through use of ulogd
(http://www.netfilter.org/projects/ulogd/index.html).

For a description of log levels, see http://www.shorewall.net/shorewall_logging.html.

If you don't want to log but need to specify the following column, place "-" here.

BURST:LIMIT (limit) - [{s|d}:[[name]:]]]rate/{second|minute}[:burst]
If passed, specifies the maximum TCP connection rate and the size of an acceptable
burst. If not specified, TCP connections are not limited. If the burst parameter is
omitted, a value of 5 is assumed.

When s: or d: is specified, the rate applies per source IP address or per destination
IP address respectively. The name may be chosen by the user and specifies a hash table
to be used to count matching connections. If not give, the name shorewall is assumed.
Where more than one POLICY specifies the same name, the connections counts for the
policies are aggregated and the individual rates apply to the aggregated count.

CONNLIMIT - limit[:mask]
May be used to limit the number of simultaneous connections from each individual host
to limit connections. While the limit is only checked on connections to which this
policy could apply, the number of current connections is calculated over all current
connections from the SOURCE host. By default, the limit is applied to each host
individually but can be made to apply to networks of hosts by specifying a mask. The
mask specifies the width of a VLSM mask to be applied to the source address; the
number of current connections is then taken over all hosts in the subnet
source-address/mask.

EXAMPLE

        1. All connections from the local network to the internet are allowed

        2. All connections from the internet are ignored but logged at syslog level KERNEL.INFO.

        3. All other connection requests are rejected and logged at level KERNEL.INFO.

                   #SOURCE         DEST            POLICY          LOG           BURST:LIMIT
                   #                                               LEVEL
                   loc             net             ACCEPT
                   net             all             DROP            info
                   #
                   # THE FOLLOWING POLICY MUST BE LAST
                   #
                   all             all             REJECT          info

FILES

       /etc/shorewall6/policy

NOTES