shorewall-rules(5)
NAME
rules - Shorewall rules file
SYNOPSIS
/etc/shorewall/rules
DESCRIPTION
Entries in this file govern connection establishment by defining
exceptions to the policies laid out in shorewall-policy[1](5). By
default, subsequent requests and responses are automatically allowed
using connection tracking. For any particular (source,dest) pair of
zones, the rules are evaluated in the order in which they appear in
this file and the first terminating match is the one that determines
the disposition of the request. All rules are terminating except LOG
and COUNT rules.
Warning
If you masquerade or use SNAT from a local system to the internet,
you cannot use an ACCEPT rule to allow traffic from the internet to
that system. You must use a DNAT rule instead.
The rules file is divided into sections. Each section is introduced by
a "Section Header" which is a line beginning with ?SECTION and followed
by the section name.
Sections are as follows and must appear in the order listed:
ALL
This section was added in Shorewall 4.4.23. Rules in this section
are applied, regardless of the connection tracking state of the
packet.
ESTABLISHED
Packets in the ESTABLISHED state are processed by rules in this
section.
The only ACTIONs allowed in this section are ACCEPT, DROP, REJECT,
LOG and QUEUE
There is an implicit ACCEPT rule inserted at the end of this
section.
RELATED
Packets in the RELATED state are processed by rules in this
section.
The only ACTIONs allowed in this section are ACCEPT, DROP, REJECT,
LOG and QUEUE
There is an implicit rule added at the end of this section that
invokes the RELATED_DISPOSITION (shorewall.conf[2](5)).
INVALID
Added in Shorewall 4.5.13. Packets in the INVALID state are
processed by rules in this section.
The only Actions allowed in this section are ACCEPT, DROP, REJECT,
LOG and QUEUE.
There is an implicit rule added at the end of this section that
invokes the INVALID_DISPOSITION (shorewall.conf[2](5)).
UNTRACKED
Added in Shorewall 4.5.13. Packets in the UNTRACKED state are
processed by rules in this section.
The only Actions allowed in this section are ACCEPT, DROP, REJECT,
LOG and QUEUE.
There is an implicit rule added at the end of this section that
invokes the UNTRACKED_DISPOSITION (shorewall.conf[2](5)).
NEW
Packets in the NEW state are processed by rules in this section. If
the INVALID and/or UNTRACKED sections are empty or not included,
then the packets in the corresponding state(s) are also processed
in this section.
Note
If you are not familiar with Netfilter to the point where you are
comfortable with the differences between the various connection
tracking states, then it is suggested that you omit the ESTABLISHED
and RELATED sections and place all of your non-blacklisting rules
in the NEW section (That's after the line that reads ?SECTION
NEW').
Warning
If you specify FASTACCEPT=Yes in shorewall.conf[2](5) then the ALL,
ESTABLISHED and RELATED sections must be empty.
An except is made if you are running Shorewall 4.4.27 or later and
you have specified a non-default value for RELATED_DISPOSITION or
RELATED_LOG_LEVEL. In that case, you may have rules in the RELATED
section of this file.
You may omit any section that you don't need. If no Section Headers
appear in the file then all rules are assumed to be in the NEW section.
When defining rules that rewrite the destination IP address and/or port
number (namely DNAT and REDIRECT rules), it is important to keep
straight which columns in the file specify the packet before rewriting
and which specify how the packet will look after rewriting.
* The DEST column specifies the final destination for the packet
after rewriting and can include the final IP address and/or port
number.
* The remaining columns specify characteristics of the packet before
rewriting. In particular, the ORIGDEST column gives the original
destination IP address of the packet and the DPORT column give the
original destination port(s).
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).
ACTION - target[:{log-level|none}[!][:tag]]
Specifies the action to be taken if the connection request matches
the rule. target must be one of the following.
ACCEPT
Allow the connection request.
ACCEPT+
like ACCEPT but also excludes the connection from any
subsequent matching DNAT[-] or REDIRECT[-] rules.
ACCEPT!
like ACCEPT but exempts the rule from being suppressed by
OPTIMIZE=1 in shorewall.conf[2](5).
action
The name of an action declared in shorewall-actions[3](5) or in
/usr/share/shorewall/actions.std.
ADD(ipset:flags[:timeout])
Added in Shorewall 4.4.12. Causes addresses and/or port numbers
to be added to the named ipset. The flags specify the address
or tuple to be added to the set and must match the type of
ipset involved. For example, for an iphash ipset, either the
SOURCE or DESTINATION address can be added using flagssrc or
dst respectively (see the -A command in ipset (8)).
Beginning with Shorewall 5.0.3, an optional timeout can be
specified. This is the number of seconds that the new entry in
the ipset is to remain valid and overrides any timeout
specified when the ipset was created.
ADD is non-terminating. Even if a packet matches the rule, it
is passed on to the next rule.
AUDIT[(accept|drop|reject)]
Added in Shorewall 4.5.10. Audits the packet with the specified
type; if the type is omitted, then drop is assumed. Require
AUDIT_TARGET support in the kernel and iptables.
A_ACCEPT, A_ACCEPT+ and A_ACCEPT!
Added in Shorewall 4.4.20. Audited versions of ACCEPT, ACCEPT+
and ACCEPT! respectively. Require AUDIT_TARGET support in the
kernel and iptables.
A_DROP and A_DROP!
Added in Shorewall 4.4.20. Audited versions of DROP and DROP!
respectively. Require AUDIT_TARGET support in the kernel and
iptables.
A_REJECT AND A_REJECT!
Added in Shorewall 4.4.20. Audited versions of REJECT and
REJECT! respectively. Require AUDIT_TARGET support in the
kernel and iptables.
?COMMENT
the rest of the line will be attached as a comment to the
Netfilter rule(s) generated by the following entries. The
comment will appear delimited by "/* ... */" in the output of
"shorewall show <chain>". To stop the comment from being
attached to further rules, simply include ?COMMENT on a line by
itself.
CONMARK({mark})
Added in Shorewall 5.0.7, CONNMARK is identical to MARK with
the exception that the mark is assigned to connection to which
the packet belongs is marked rather than to the packet itself.
CONTINUE
For experts only.
Do not process any of the following rules for this (source
zone,destination zone). If the source and/or destination IP
address falls into a zone defined later in
shorewall-zones[4](5) or in a parent zone of the source or
destination zones, then this connection request will be passed
to the rules defined for that (those) zone(s). See
shorewall-nesting[5](5) for additional information.
CONTINUE!
like CONTINUE but exempts the rule from being suppressed by
OPTIMIZE=1 in shorewall.conf[2](5).
COUNT
Simply increment the rule's packet and byte count and pass the
packet to the next rule.
DEL(ipset:flags)
Added in Shorewall 4.4.12. Causes an entry to be deleted from
the named ipset. The flags specify the address or tuple to be
deleted from the set and must match the type of ipset involved.
For example, for an iphash ipset, either the SOURCE or
DESTINATION address can be deleted using flagssrc or dst
respectively (see the -D command in ipset (8)).
DEL is non-terminating. Even if a packet matches the rule, it
is passed on to the next rule.
DNAT
Forward the request to another system (and optionally another
port).
DNAT-
Advanced users only.
Like DNAT but only generates the DNAT iptables rule and not the
companion ACCEPT rule.
DROP
Ignore the request.
DROP!
like DROP but exempts the rule from being suppressed by
OPTIMIZE=1 in shorewall.conf[2](5).
HELPER
Added in Shorewall 4.5.7. This action requires that the HELPER
column contains the name of the Netfilter helper to be
associated with connections matching this connection. May only
be specified in the NEW section and is useful for being able to
specify a helper when the applicable policy is ACCEPT. No
destination zone should be specified in HELPER rules.
INLINE[(action)]
Added in Shorewall 4.5.16. This action allows you to construct
most of the rule yourself using iptables syntax. The part that
you specify must follow a semicolon (';') and is completely
free-form. If the target of the rule (the part following 'j')
is something that Shorewall supports in the ACTION column, then
you may enclose it in parentheses (e.g., INLINE(ACCEPT)).
Otherwise, you can include it after the semicolon. In this
case, you must declare the target as a builtin action in
shorewall-actions[3](5).
Some considerations when using INLINE:
* The p, s, d, i, o, policy, and state match (state or
conntrack --ctstate) matches will always appear in the
front of the rule in that order.
* When multiple matches are specified, the compiler will keep
them in the order in which they appear (excluding the above
listed ones), but they will not necessarily be at the end
of the generated rule. For example, if addresses are
specified in the SOURCE and/or DEST columns, their
generated matches will appear after those specified using
';'.
IPTABLES({iptables-target [option ...])
This action allows you to specify an iptables target with
options (e.g., 'IPTABLES(MARK --set-xmark 0x01/0xff)'. If the
iptables-target is not one recognized by Shorewall, the
following error message will be issued:
ERROR: Unknown target (iptables-target)
This error message may be eliminated by adding the
iptables-target as a builtin action in shorewall-actions[3](5).
Important
If you specify REJECT as the iptables-target, the target of
the rule will be the iptables REJECT target and not
Shorewall's builtin 'reject' chain which is used when
REJECT (see below) is specified as the target in the ACTION
column.
LOG:level
Simply log the packet and continue with the next rule.
macro[(macrotarget)]
The name of a macro defined in a file named macro.macro. If the
macro accepts an action parameter (Look at the macro source to
see if it has PARAM in the TARGET column) then the macro name
is followed by the parenthesized macrotarget (ACCEPT, DROP,
REJECT, ...) to be substituted for the parameter.
Example: FTP(ACCEPT).
The older syntax where the macro name and the target are
separated by a slash (e.g. FTP/ACCEPT) is still allowed but is
deprecated.
MARK({mark})
where mark is a packet mark value.
Added in Shorewall 5.0.7, MARK requires "Mark in filter table"
support in your kernel and iptables.
Normally will set the mark value of the current packet. If
preceded by a vertical bar ("|"), the mark value will be
logically ORed with the current mark value to produce a new
mark value. If preceded by an ampersand ("&"), will be
logically ANDed with the current mark value to produce a new
mark value.
Both "|" and "&" require Extended MARK Target support in your
kernel and iptables.
The mark value may be optionally followed by "/" and a mask
value (used to determine those bits of the connection mark to
actually be set). When a mask is specified, the result of
logically ANDing the mark value with the mask must be the same
as the mark value.
NFLOG[(nflog-parameters)]
Added in Shorewall 4.5.9.3. Queues matching packets to a back
end logging daemon via a netlink socket then continues to the
next rule. See
http://www.shorewall.net/shorewall_logging.html[6].
The nflog-parameters are a comma-separated list of up to 3
numbers:
* The first number specifies the netlink group (0-65535). If
omitted (e.g., NFLOG(,0,10)) then a value of 0 is assumed.
* The second number specifies the maximum number of bytes to
copy. If omitted, 0 (no limit) is assumed.
* The third number specifies the number of log messages that
should be buffered in the kernel before they are sent to
user space. The default is 1.
NFLOG is similar to LOG:NFLOG[(nflog-parameters)], except that
the log level is not changed when this ACTION is used in an
action or macro body and the invocation of that action or macro
specifies a log level.
NFQUEUE[([queuenumber1[:queuenumber2][,bypass]]|bypass)]
Queues the packet to a user-space application using the
nfnetlink_queue mechanism. If a queuenumber1 is not specified,
queue zero (0) is assumed. Beginning with Shorewall 4.6.10, the
keyword bypass can be given. By default, if no userspace
program is listening on an NFQUEUE, then all packets that are
to be queued are dropped. When this option is used, the NFQUEUE
rule is silently bypassed instead. The packet will move on to
the next rule. Also beginning in Shorewall 4.6.10, a second
queue number (queuenumber2) may be specified. This specifies a
range of queues to use. Packets are then balanced across the
given queues. This is useful for multicore systems: start
multiple instances of the userspace program on queues x, x+1,
.. x+n and use "x:x+n". Packets belonging to the same
connection are put into the same nfqueue.
NFQUEUE![([queuenumber1[,queuenumber2][,bypass]]|bypass)]
like NFQUEUE but exempts the rule from being suppressed by
OPTIMIZE=1 in shorewall.conf[2](5).
NONAT
Excludes the connection from any subsequent DNAT[-] or
REDIRECT[-] rules but doesn't generate a rule to accept the
traffic.
QUEUE
Queue the packet to a user-space application such as ftwall
(http://p2pwall.sf.net). The application may reinsert the
packet for further processing.
QUEUE!
like QUEUE but exempts the rule from being suppressed by
OPTIMIZE=1 in shorewall.conf[2](5).
REJECT[(option)]
disallow the request and return an icmp-unreachable or an RST
packet. If no option is passed, Shorewall selects the
appropriate option based on the protocol of the packet.
Beginning with Shorewall 5.0.8, the type of reject may be
specified in the option paramater. Valid option values are:
icmp-net-unreachable
icmp-host-unreachable
icmp-port-unreachable
icmp-proto-unreachable
icmp-net-prohibited
icmp-host-prohibited
icmp-admin-prohibited
icmp-tcp-reset (the PROTO column
must specify TCP)
REJECT!
like REJECT but exempts the rule from being suppressed by
OPTIMIZE=1 in shorewall.conf[2](5).
REDIRECT
Redirect the request to a server running on the firewall.
REDIRECT-
Advanced users only.
Like REDIRECT but only generates the REDIRECT iptables rule and
not the companion ACCEPT rule.
TARPIT [(tarpit | honeypot | reset)]
Added in Shorewall 4.6.6.
TARPIT captures and holds incoming TCP connections using no
local per-connection resources.
TARPIT only works with the PROTO column set to tcp (6), and is
totally application agnostic. This module will answer a TCP
request and play along like a listening server, but aside from
sending an ACK or RST, no data is sent. Incoming packets are
ignored and dropped. The attacker will terminate the session
eventually. This module allows the initial packets of an attack
to be captured by other software for inspection. In most cases
this is sufficient to determine the nature of the attack.
This offers similar functionality to LaBrea
<http://www.hackbusters.net/LaBrea/> but does not require
dedicated hardware or IPs. Any TCP port that you would normally
DROP or REJECT can instead become a tarpit.
The target accepts a single optional parameter:
tarpit
This mode is the default and completes a connection with
the attacker but limits the window size to 0, thus keeping
the attacker waiting long periods of time. While he is
maintaining state of the connection and trying to continue
every 60-240 seconds, we keep none, so it is very
lightweight. Attempts to close the connection are ignored,
forcing the remote side to time out the connection in 12-24
minutes.
honeypot
This mode completes a connection with the attacker, but
signals a normal window size, so that the remote side will
attempt to send data, often with some very nasty exploit
attempts. We can capture these packets for decoding and
further analysis. The module does not send any data, so if
the remote expects an application level response, the game
is up.
reset
This mode is handy because we can send an inline RST
(reset). It has no other function.
ULOG[(ulog-parameters)]
Added in Shorewall 4.5.10. Queues matching packets to a back
end logging daemon via a netlink socket then continues to the
next rule. See
http://www.shorewall.net/shorewall_logging.html[6].
Similar to LOG:ULOG[(ulog-parameters)], except that the log
level is not changed when this ACTION is used in an action or
macro body and the invocation of that action or macro specifies
a log level.
The target may optionally be followed by ":" and a syslog log level
(e.g, REJECT:info or Web(ACCEPT):debug). This causes the packet to
be logged at the specified level. Note that if the ACTION involves
destination network address translation (DNAT, REDIRECT, etc.) then
the packet is logged before the destination address is rewritten.
If the ACTION names an action declared in shorewall-actions[3](5)
or in /usr/share/shorewall/actions.std then:
* If the log level is followed by "!' then all rules in the
action are logged at the log level.
* If the log level is not followed by "!" then only those rules
in the action that do not specify logging are logged at the
specified level.
* The special log level none! suppresses logging by the action.
You may also specify ULOG or NFLOG (must be in upper case) as a log
level.This will log to the ULOG or NFLOG target for routing to a
separate log through use of ulogd
(http://www.netfilter.org/projects/ulogd/index.html).
Actions specifying logging may be followed by a log tag (a string
of alphanumeric characters) which is appended to the string
generated by the LOGPREFIX (in shorewall.conf[2](5)).
Example: ACCEPT:info:ftp would include 'ftp ' at the end of the log
prefix generated by the LOGPREFIX setting.
SOURCE -
{zone|zone-list[+]|{all|any}[+][-]}[:interface][:{address-or-range[,address-or-range]...[exclusion]|exclusion|+ipset|^countrycode-list}
Source hosts to which the rule applies. May be a zone declared in
/etc/shorewall/zones, $FW to indicate the firewall itself, all,
all+, all-, all+- or none.
Beginning with Shorewall 4.4.13, you may use a zone-list which
consists of a comma-separated list of zones declared in
shorewall-zones[4] (5). This zone-list may be optionally followed
by "+" to indicate that the rule is to apply to intra-zone traffic
as well as inter-zone traffic.
When none is used either in the SOURCE or DEST column, the rule is
ignored.
all means "All Zones", including the firewall itself. all- means
"All Zones, except the firewall itself". When all[-] is used either
in the SOURCE or DEST column intra-zone traffic is not affected.
When all+[-] is "used, intra-zone traffic is affected. Beginning
with Shorewall 4.4.13, exclusion is supported -- see see
shorewall-exclusion[7](5).
Except when all[+][-] or any[+][-] is specified, clients may be
further restricted to a list of networks and/or hosts by appending
":" and a comma-separated list of network and/or host addresses.
Hosts may be specified by IP or MAC address; mac addresses must
begin with "~" and must use "-" as a separator.
The above restriction on all[+][-] and any[+][-] is removed in
Shorewall-4.4.13.
any is equivalent to all when there are no nested zones. When there
are nested zones, any only refers to top-level zones (those with no
parent zones). Note that any excludes all vserver zones, since
those zones are nested within the firewall zone. Beginning with
Shorewall 4.4.13, exclusion is supported with any -- see see
shorewall-exclusion[7](5).
Hosts may also be specified as an IP address range using the syntax
lowaddress-highaddress. This requires that your kernel and iptables
contain iprange match support. If your kernel and iptables have
ipset match support then you may give the name of an ipset prefaced
by "+". The ipset name may be optionally followed by a number from
1 to 6 enclosed in square brackets ([]) to indicate the number of
levels of source bindings to be matched.
Beginning with Shorewall 4.4.17, the primary IP address of a
firewall interface can be specified by an ampersand ('&') followed
by the logical name of the interface as found in the INTERFACE
column of shorewall-interfaces[8] (5).
Beginning with Shorewall 4.5.4, A countrycode-list may be
specified. A countrycode-list is a comma-separated list of up to 15
two-character ISO-3661 country codes enclosed in square brackets
('[...]') and preceded by a caret ('^'). When a single country code
is given, the square brackets may be omitted. A list of country
codes supported by Shorewall may be found at
http://www.shorewall.net/ISO-3661.html[9]. Specifying a
countrycode-list requires GeoIP Match support in your iptables and
Kernel.
You may exclude certain hosts from the set already defined through
use of an exclusion (see shorewall-exclusion[7](5)).
Examples:
dmz:192.168.2.2
Host 192.168.2.2 in the DMZ
net:155.186.235.0/24
Subnet 155.186.235.0/24 on the Internet
loc:192.168.1.1,192.168.1.2
Hosts 192.168.1.1 and 192.168.1.2 in the local zone.
loc:~00-A0-C9-15-39-78
Host in the local zone with MAC address 00:A0:C9:15:39:78.
net:192.0.2.11-192.0.2.17
Hosts 192.0.2.11-192.0.2.17 in the net zone.
net:!192.0.2.11-192.0.2.17
All hosts in the net zone except for 192.0.2.11-192.0.2.17.
net:155.186.235.0/24!155.186.235.16/28
Subnet 155.186.235.0/24 on the Internet except for
155.186.235.16/28
$FW:ð0
The primary IP address of eth0 in the firewall zone (Shorewall
4.4.17 and later).
loc,dmz
Both the loc and dmz zones.
all!dmz
All but the dmz zone.
DEST -
{zone|zone-list[+]|{all|any}[+][-]}[:{interface|address-or-range[,address-or-range]...[exclusion]|exclusion|+ipset|^countrycode-list}][:port[:random]]
Location of Server. May be a zone declared in
shorewall-zones[4](5), $FW to indicate the firewall itself, all.
all+ or none.
Beginning with Shorewall 4.4.13, you may use a zone-list which
consists of a comma-separated list of zones declared in
shorewall-zones[4] (5). This zone-list may be optionally followed
by "+" to indicate that the rule is to apply to intra-zone traffic
as well as inter-zone traffic.
Beginning with Shorewall 4.5.4, A countrycode-list may be
specified. A countrycode-list is a comma-separated list of up to 15
two-character ISO-3661 country codes enclosed in square brackets
('[...]') and preceded by a caret ('^'). When a single country code
is given, the square brackets may be omitted. A list of country
codes supported by Shorewall may be found at
http://www.shorewall.net/ISO-3661.html[9]. Specifying a
countrycode-list requires GeoIP Match support in your iptables and
Kernel.
When none is used either in the SOURCE or DEST column, the rule is
ignored.
all means "All Zones", including the firewall itself. all- means
"All Zones, except the firewall itself". When all[-] is used either
in the SOURCE or DEST column intra-zone traffic is not affected.
When all+[-] is "used, intra-zone traffic is affected. Beginning
with Shorewall 4.4.13, exclusion is supported -- see see
shorewall6-exclusion[10](5).
any is equivalent to all when there are no nested zones. When there
are nested zones, any only refers to top-level zones (those with no
parent zones). Note that any excludes all vserver zones, since
those zones are nested within the firewall zone.
Except when all[+][-] or any[+][-] is specified, clients may be
further restricted to a list of networks and/or hosts by appending
":" and a comma-separated list of network and/or host addresses.
Hosts may be specified by IP or MAC address; mac addresses must
begin with "~" and must use "-" as a separator.
When all is used either in the SOURCE or DEST column intra-zone
traffic is not affected. When all+ is used, intra-zone traffic is
affected. Beginning with Shorewall 4.4.13, exclusion is supported
-- see see shorewall-exclusion[7](5).
The zone should be omitted in DNAT-, REDIRECT- and NONAT rules.
If the DEST zone is a bport zone, then either:
1. the SOURCE must be all[+][-], or
2. the SOURCE zone must be another bport zone associated with the
same bridge, or
3. the SOURCE zone must be an ipv4 zone that is associated with
only the same bridge.
Except when {all|any}[+]|[-] is specified, the server may be
further restricted to a particular network, host or interface by
appending ":" and the network, host or interface. See SOURCE above.
You may exclude certain hosts from the set already defined through
use of an exclusion (see shorewall-exclusion[7](5)).
Restriction: MAC addresses are not allowed (this is a Netfilter
restriction).
Like in the SOURCE column, you may specify a range of IP addresses
using the syntax lowaddress-highaddress. When the ACTION is DNAT or
DNAT-, the connections will be assigned to addresses in the range
in a round-robin fashion.
If your kernel and iptables have ipset match support then you may
give the name of an ipset prefaced by "+". The ipset name may be
optionally followed by a number from 1 to 6 enclosed in square
brackets ([]) to indicate the number of levels of destination
bindings to be matched. Only one of the SOURCE and DEST columns may
specify an ipset name.
Beginning with Shorewall 4.4.17, the primary IP address of a
firewall interface can be specified by an ampersand ('&') followed
by the logical name of the interface as found in the INTERFACE
column of shorewall-interfaces[8] (5).
The port that the server is listening on may be included and
separated from the server's IP address by ":". If omitted, the
firewall will not modify the destination port. A destination port
may only be included if the ACTION is DNAT or REDIRECT.
Example:
loc:192.168.1.3:3128 specifies a local server at IP address
192.168.1.3 and listening on port 3128.
The port may be specified as a service name. You may specify a port
range in the form lowport-highport to cause connections to be
assigned to ports in the range in round-robin fashion. When a port
range is specified, lowport and highport must be given as integers;
service names are not permitted. Additionally, the port range may
be optionally followed by :random which causes assignment to ports
in the list to be random.
If the ACTION is REDIRECT or REDIRECT-, this column needs only to
contain the port number on the firewall that the request should be
redirected to. That is equivalent to specifying $FW::port.
PROTO-
{-|tcp:syn|ipp2p|ipp2p:udp|ipp2p:all|protocol-number|protocol-name|all}
Optional Protocol - ipp2p* requires ipp2p match support in your
kernel and iptables. tcp:syn implies tcp plus the SYN flag must be
set and the RST,ACK and FIN flags must be reset.
Beginning with Shorewall 4.4.19, this column can contain a
comma-separated list of protocol-numbers and/or protocol names.
DPORT -
{-|port-name-number-or-range[,port-name-number-or-range]...|+ipset}
Optional destination Ports. A comma-separated list of Port names
(from services(5)), port numbers or port ranges; if the protocol is
icmp, this column is interpreted as the destination icmp-type(s).
ICMP types may be specified as a numeric type, a numeric type and
code separated by a slash (e.g., 3/4), or a typename. See
http://www.shorewall.net/configuration_file_basics.htm#ICMP[11].
Note that prior to Shorewall 4.4.19, only a single ICMP type may be
listed.
If the protocol is ipp2p, this column is interpreted as an ipp2p
option without the leading "--" (example bit for bit-torrent). If
no port is given, ipp2p is assumed.
A port range is expressed as lowport:highport.
This column is ignored if PROTO = all but must be entered if any of
the following columns are supplied. In that case, it is suggested
that this field contain a dash (-).
If your kernel contains multi-port match support, then only a
single Netfilter rule will be generated if in this list and the
SPORT list below:
1. There are 15 or less ports listed.
2. No port ranges are included or your kernel and iptables contain
extended multi-port match support.
Beginning with Shorewall 4.6.0, an ipset name can be specified in
this column. This is intended to be used with bitmap:port ipsets.
This column was formerly labelled DEST PORT(S).
SPORT -
{-|port-name-number-or-range[,port-name-number-or-range]...|+ipset}
Optional port(s) used by the client. If omitted, any source port is
acceptable. Specified as a comma- separated list of port names,
port numbers or port ranges.
Beginning with Shorewall 4.5.15, you may place '=' in this column,
provided that the DPORT column is non-empty. This causes the rule
to match when either the source port or the destination port in a
packet matches one of the ports specified in DEST PORTS(S). Use of
'=' requires multi-port match in your iptables and kernel.
Warning
Unless you really understand IP, you should leave this column
empty or place a dash (-) in the column. Most people who try to
use this column get it wrong.
If you don't want to restrict client ports but need to specify an
ORIGDEST in the next column, then place "-" in this column.
If your kernel contains multi-port match support, then only a
single Netfilter rule will be generated if in this list and the
DPORT list above:
1. There are 15 or less ports listed.
2. No port ranges are included or your kernel and iptables contain
extended multi-port match support.
Beginning with Shorewall 4.6.0, an ipset name can be specified in
this column. This is intended to be used with bitmap:port ipsets.
This column was formerly labelled SOURCE PORT(S).
ORIGDEST - [-|address[,address]...[exclusion]|exclusion]
Optional. If ACTION is DNAT[-] or REDIRECT[-] then if this column
is included and is different from the IP address given in the DEST
column, then connections destined for that address will be
forwarded to the IP and port specified in the DEST column.
A comma-separated list of addresses may also be used. This is most
useful with the REDIRECT target where you want to redirect traffic
destined for particular set of hosts. Finally, if the list of
addresses begins with "!" (exclusion) then the rule will be
followed only if the original destination address in the connection
request does not match any of the addresses listed.
Beginning with Shorewall 4.4.17, the primary IP address of a
firewall interface can be specified by an ampersand ('&') followed
by the logical name of the interface as found in the INTERFACE
column of shorewall-interfaces[8] (5).
For other actions, this column may be included and may contain one
or more addresses (host or network) separated by commas. Address
ranges are not allowed. When this column is supplied, rules are
generated that require that the original destination address
matches one of the listed addresses. This feature is most useful
when you want to generate a filter rule that corresponds to a DNAT-
or REDIRECT- rule. In this usage, the list of addresses should not
begin with "!".
It is also possible to specify a set of addresses then exclude part
of those addresses. For example, 192.168.1.0/24!192.168.1.16/28
specifies the addresses 192.168.1.0-182.168.1.15 and
192.168.1.32-192.168.1.255. See shorewall-exclusion[7](5).
See http://www.shorewall.net/PortKnocking.html[12] for an example
of using an entry in this column with a user-defined action rule.
This column was formerly labelled ORIGINAL DEST.
RATE - limit
where limit is one of:
[-|[{s|d}:[[name]:]]]rate/{sec|min|hour|day}[:burst]
[name1]:rate1/{sec|min|hour|day}[:burst1],[name2]:rate2/{sec|min|hour|day}[:burst2]
You may optionally rate-limit the rule by placing a value in this
column:
rate* is the number of connections per interval (sec or min) and
burst* is the largest burst permitted. If no burst is given, a
value of 5 is assumed. There may be no no white-space embedded in
the specification.
Example: 10/sec:20
When s: or d: is specified, the rate applies per source IP address
or per destination IP address respectively. The names may be chosen
by the user and specify a hash table to be used to count matching
connections. If not given, the name shorewallN (where N is a unique
integer) is assumed. Where more than one rule or POLICY specifies
the same name, the connections counts for the rules are aggregated
and the individual rates apply to the aggregated count.
Beginning with Shorewall 4.6.5, two limits may be specified,
separated by a comma. In this case, the first limit (name1, rate1,
burst1) specifies the per-source IP limit and the second limit
specifies the per-destination IP limit.
Example: client:10/sec:20,:60/sec:100
In this example, the 'client' hash table will be used to enforce
the per-source limit and the compiler will pick a unique name for
the hash table that tracks the per-destination limit.
This column was formerly labelled RATE LIMIT.
USER - [!][user-name-or-number][:group-name-or-number][,...]
This optional column may only be non-empty if the SOURCE is the
firewall itself.
When this column is non-empty, the rule applies only if the program
generating the output is running under the effective user and/or
group specified (or is NOT running under that id if "!" is given).
Beginning with Shorewall 4.5.8, multiple user or group names/ids
separated by commas may be specified.
Examples:
joe
program must be run by joe
:kids
program must be run by a member of the 'kids' group
!:kids
program must not be run by a member of the 'kids' group
2001-2099
UIDs 2001 through 2099 (Shorewall 4.5.6 and later)
This column was formerly labelled USER/GROUP.
MARK - [!]value[/mask][:C]
Defines a test on the existing packet or connection mark. The rule
will match only if the test returns true.
If you don't want to define a test but need to specify anything in
the following columns, place a "-" in this field.
!
Inverts the test (not equal)
value
Value of the packet or connection mark.
mask
A mask to be applied to the mark before testing.
:C
Designates a connection mark. If omitted, the packet mark's
value is tested.
CONNLIMIT - [d:][!]limit[:mask]
May be used to limit the number of simultaneous connections to/from
each individual host or network to limit connections. Requires
connlimit match in your kernel and iptables. While the limit is
only checked on rules specifying CONNLIMIT, the number of current
connections is calculated over all current connections from the
SOURCE or DESTINATION host. By default, limiting is done by SOURCE
host or net, but if the specification begins with d:, then limiting
will be donw by destination host or net.
By default, the limit is applied to each host 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. When ! is specified, the rule matches
when the number of connection exceeds the limit.
TIME - timeelement[&timeelement...]
May be used to limit the rule to a particular time period each day,
to particular days of the week or month, or to a range defined by
dates and times. Requires time match support in your kernel and
iptables.
timeelement may be:
timestart=hh:mm[:ss]
Defines the starting time of day.
timestop=hh:mm[:ss]
Defines the ending time of day.
contiguous
Added in Shoreawll 5.0.12. When timestop is smaller than
timestart value, match this as a single time period instead of
distinct intervals.
utc
Times are expressed in Greenwich Mean Time.
localtz
Deprecated by the Netfilter team in favor of kerneltz. Times
are expressed in Local Civil Time (default).
kerneltz
Added in Shorewall 4.5.2. Times are expressed in Local Kernel
Time (requires iptables 1.4.12 or later).
weekdays=ddd[,ddd]...
where ddd is one of Mon, Tue, Wed, Thu, Fri, Sat or Sun
monthdays=dd[,dd],...
where dd is an ordinal day of the month
datestart=yyyy[-mm[-dd[Thh[:mm[:ss]]]]]
Defines the starting date and time.
datestop=yyyy[-mm[-dd[Thh[:mm[:ss]]]]]
Defines the ending date and time.
HEADERS
Added in Shorewall 4.4.15. Not used in IPv4 configurations. If you
with to supply a value for one of the later columns, enter '-' in
this column.
SWITCH - [!]switch-name[={0|1}]
Added in Shorewall 4.4.24 and allows enabling and disabling the
rule without requiring shorewall restart.
The rule is enabled if the value stored in
/proc/net/nf_condition/switch-name is 1. The rule is disabled if
that file contains 0 (the default). If '!' is supplied, the test is
inverted such that the rule is enabled if the file contains 0.
Within the switch-name, '@0' and '@{0}' are replaced by the name of
the chain to which the rule is a added. The switch-name (after
'@...' expansion) must begin with a letter and be composed of
letters, decimal digits, underscores or hyphens. Switch names must
be 30 characters or less in length.
Switches are normally off. To turn a switch on:
echo 1 >
/proc/net/nf_condition/switch-name
To turn it off again:
echo 0 >
/proc/net/nf_condition/switch-name
Switch settings are retained over shorewall restart.
Beginning with Shorewall 4.5.10, when the switch-name is followed
by =0 or =1, then the switch is initialized to off or on
respectively by the start command. Other commands do not affect the
switch setting.
HELPER - [helper]
Added in Shorewall 4.5.7.
In the NEW section, causes the named conntrack helper to be
associated with this connection; the contents of this column are
ignored unless ACTION is ACCEPT*, DNAT* or REDIRECT*.
In the RELATED section, will only match if the related connection
has the named helper associated with it.
The helper may be one of:
amanda
ftp
irc
netbios-ns
pptp
Q.931
RAS
sane
sip
snmp
tftp
If the HELPERS option is specified in shorewall.conf[2](5), then
any module specified in this column must be listed in the HELPERS
setting.
EXAMPLES
Example 1:
Accept SMTP requests from the DMZ to the internet
#ACTION SOURCE DEST PROTO DPORT SPORT ORIGDEST
ACCEPT dmz net tcp smtp
Example 2:
Forward all ssh and http connection requests from the internet to
local system 192.168.1.3
#ACTION SOURCE DEST PROTO DPORT SPORT ORIGDEST
DNAT net loc:192.168.1.3 tcp ssh,http
Example 3:
Forward all http connection requests from the internet to local
system 192.168.1.3 with a limit of 3 per second and a maximum burst
of 10
#ACTION SOURCE DEST PROTO DPORT SPORT ORIGDEST RATE
DNAT net loc:192.168.1.3 tcp http - - 3/sec:10
Example 4:
Redirect all locally-originating www connection requests to port
3128 on the firewall (Squid running on the firewall system) except
when the destination address is 192.168.2.2
#ACTION SOURCE DEST PROTO DPORT SPORT ORIGDEST
REDIRECT loc 3128 tcp www - !192.168.2.2
Example 5:
All http requests from the internet to address 130.252.100.69 are
to be forwarded to 192.168.1.3
#ACTION SOURCE DEST PROTO DPORT SPORT ORIGDEST
DNAT net loc:192.168.1.3 tcp 80 - 130.252.100.69
Example 6:
You want to accept SSH connections to your firewall only from
internet IP addresses 130.252.100.69 and 130.252.100.70
#ACTION SOURCE DEST PROTO DPORT SPORT ORIGDEST
ACCEPT net:130.252.100.69,130.252.100.70 \
$FW tcp 22
Example 7:
You wish to accept connections from the internet to your firewall
on port 2222 and you want to forward them to local system
192.168.1.3, port 22
#ACTION SOURCE DEST PROTO DPORT SPORT ORIGDEST
DNAT net loc:192.168.1.3:22 tcp 2222
Example 8:
You want to redirect connection requests to port 80 randomly to the
port range 81-90.
#ACTION SOURCE DEST PROTO DPORT SPORT ORIGDEST
REDIRECT net $FW::81-90:random tcp www
Example 9:
Shorewall does not impose as much structure on the Netfilter rules
in the 'nat' table as it does on those in the filter table. As a
consequence, when using Shorewall versions before 4.1.4, care must
be exercised when using DNAT and REDIRECT rules with zones defined
with wildcard interfaces (those ending with '+'. Here is an
example:
shorewall-zones[4](5):
#ZONE TYPE OPTIONS
fw firewall
net ipv4
dmz ipv4
loc ipv4
shorewall-interfaces[8](5):
#ZONE INTERFACE BROADCAST OPTIONS
net ppp0
loc eth1 detect
dmz eth2 detect
- ppp+ # Addresses are assigned from 192.168.3.0/24
shorewall-host[13](5):
#ZONE HOST(S) OPTIONS
loc ppp+:192.168.3.0/24
rules:
#ACTION SOURCE DEST PROTO DPORT
REDIRECT loc 3128 tcp 80
Note that it would have been tempting to simply define the loc zone
entirely in shorewall-interfaces(8):
#******************* INCORRECT *****************
#ZONE INTERFACE BROADCAST OPTIONS
net ppp0
loc eth1 detect
loc ppp+
dmz eth2
This would have made it impossible to run a internet-accessible web
server in the DMZ because all traffic entering ppp+ interfaces
would have been redirected to port 3128 on the firewall and there
would have been no net->fw ACCEPT rule for that traffic.
Example 10:
Add the tuple (source IP, dest port, dest IP) of an incoming SSH
connection to the ipset S:
#ACTION SOURCE DEST PROTO DPORT
ADD(+S:dst,src,dst) net fw tcp 22
Example 11:
You wish to limit SSH connections from remote systems to 1/min with
a burst of three (to allow for limited retry):
#ACTION SOURCE DEST PROTO DPORT SPORT ORIGDEST RATE
SSH(ACCEPT) net all - - - - s:1/min:3
Example 12:
Forward port 80 to dmz host $BACKUP if switch 'primary_down' is on.
#ACTION SOURCE DEST PROTO DPORT SPORT ORIGDEST RATE USER MARK CONNLIMIT TIME HEADERS SWITCH
DNAT net dmz:$BACKUP tcp 80 - - - - - - - - primary_down
Example 13:
Drop all email from the Anonymous Proxy and Satellite Provider
address ranges:
#ACTION SOURCE DEST PROTO DPORT
DROP net:^A1,A2 fw tcp 25
Example 14:
You want to generate your own rule involving iptables targets and
matches not supported by Shorewall.
#ACTION SOURCE DEST PROTO DPORT
INLINE $FW net ; -p 6 -m mickey-mouse --name test -m set --match-set set1 src -m mickey-mouse --name test2 -j SECCTX --name test3
The above will generate the following iptables-restore input:
-A fw2net -p 6 -m mickey-mouse --name test -m set --match-set set1 src -m mickey-mouse --name test2 -j SECCTX --name test3
Note that SECCTX must be defined as a builtin action in
shorewall-actions[3](5):
#ACTION OPTIONS
SECCTX builtin
FILES
/etc/shorewall/rules
SEE ALSO
http://www.shorewall.net/ipsets.html[14] http://www.shorewall.net/configuration_file_basics.htm#Pairs[15] http://www.shorewall.net/shorewall_logging.html[16] shorewall(8), shorewall-accounting(5), shorewall-actions(5), shorewall-blacklist(5), shorewall-blrules(5), shorewall-hosts(5), shorewall_interfaces(5), shorewall-ipsets(5), shorewall-maclist(5), shorewall-masq(5), shorewall-nat(5), shorewall-netmap(5), shorewall-params(5), shorewall-policy(5), shorewall-providers(5), shorewall-proxyarp(5), shorewall-rtrules(5), shorewall-routestopped(5), shorewall.conf(5), shorewall-secmarks(5), shorewall-tcclasses(5), shorewall-tcdevices(5), shorewall-mangle(5), shorewall-tos(5), shorewall-tunnels(5), shorewall-zones(5)
NOTES
1. shorewall-policy
http://www.shorewall.net/manpages/shorewall-policy.html
2. shorewall.conf
http://www.shorewall.net/manpages/shorewall.conf.html
3. shorewall-actions
http://www.shorewall.net/manpages/shorewall-actions.html
4. shorewall-zones
http://www.shorewall.net/manpages/shorewall-zones.html
5. shorewall-nesting
http://www.shorewall.net/manpages/shorewall-nesting.html
6. http://www.shorewall.net/shorewall_logging.html
http://www.shorewall.net/shorewall.logging.html
7. shorewall-exclusion
http://www.shorewall.net/manpages/shorewall-exclusion.html
8. shorewall-interfaces
http://www.shorewall.net/manpages/shorewall-interfaces.html
9. http://www.shorewall.net/ISO-3661.html
http://www.shorewall.net/ISO-3661.html
10. shorewall6-exclusion
http://www.shorewall.net/manpages6/shorewall6-exclusion.html
11. http://www.shorewall.net/configuration_file_basics.htm#ICMP
http://www.shorewall.net/configuration_file_basics.htm#ICMP
12. http://www.shorewall.net/PortKnocking.html
http://www.shorewall.net/PortKnocking.html
13. shorewall-host
http://www.shorewall.net/manpages/shorewall-hosts.html
14. http://www.shorewall.net/ipsets.html
http://www.shorewall.net/ipsets.html
15. http://www.shorewall.net/configuration_file_basics.htm#Pairs
http://www.shorewall.net/configuration_file_basics.htm#Pairs
16. http://www.shorewall.net/shorewall_logging.html
http://www.shorewall.net/shorewall_logging.html
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