shorewall-rules5rulesShorewall rules file/etc/shorewall/rulesDescriptionEntries in this file govern connection establishment by defining
exceptions to the policies layed out in shorewall-policy(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.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:ESTABLISHEDPackets in the ESTABLISHED state are processed by rules in
this section.The only ACTIONs allowed in this section are ACCEPT, DROP,
REJECT, LOG and QUEUEThere is an implicit ACCEPT rule inserted at the end of this
section.RELATEDPackets in the RELATED state are processed by rules in this
section.The only ACTIONs allowed in this section are ACCEPT, DROP,
REJECT, LOG and QUEUEThere is an implicit ACCEPT rule inserted at the end of this
section.NEWPackets in the NEW, INVALID and UNTRACKED states are processed
by rules in this section.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 rules in
the NEW section (That's after the line that reads SECTION NEW').If you specify FASTACCEPT=Yes in shorewall.conf(5) then the ESTABLISHED and RELATED sections must be empty.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 ORIGINAL DEST column gives the
original destination IP address of the packet and the DEST PORT(S)
column give the original destination port(s).The columns in the file are as follows.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.ACCEPTAllow the connection request.ACCEPT+like ACCEPT but also excludes the connection from any
subsequent matching DNAT[-] or REDIRECT[-] rulesACCEPT!like ACCEPT but exempts the rule from being suppressed
by OPTIMIZE=1 in shorewall.conf(5).NONATExcludes the connection from any subsequent DNAT[-] or REDIRECT[-] rules but doesn't generate
a rule to accept the traffic.DROPIgnore the request.DROP!like DROP but exempts the rule from being suppressed by
OPTIMIZE=1 in shorewall.conf(5).REJECTdisallow the request and return an icmp-unreachable or
an RST packet.REJECT!like REJECT but exempts the rule from being suppressed
by OPTIMIZE=1 in shorewall.conf(5).DNATForward 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.REDIRECTRedirect 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.CONTINUEFor 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(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) for
additional information.CONTINUE!like CONTINUE but exempts the rule from being suppressed
by OPTIMIZE=1 in shorewall.conf(5).LOGSimply log the packet and continue with the next
rule.QUEUEQueue 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(5).NFQUEUE[(queuenumber)]Queues the packet to a user-space application using the
nfnetlink_queue mechanism. If a
queuenumber is not specified, queue
zero (0) is assumed.NFQUEUE![(queuenumber)]like NFQUEUE but exempts the rule from being suppressed
by OPTIMIZE=1 in shorewall.conf(5).COUNTSimply increment the rule's packet and byte count and
pass the packet to the next rule.COMMENTthe 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.actionThe name of an action declared in
shorewall-actions(5) or
in /usr/share/shorewall/actions.std.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.TRIGGER(trigger[:direction])Added in Shorewall 4.4.12. Causes either the SOURCE or
DESTINATION address of the connection to be added to the named
trigger. By default, the SOURCE
address is added to the trigger but if
direction is
(e.g., trig:d) then the DESTINATION address is added. See the
TRIGGER column below.When a TRIGGER rule is placed in the NEW section, the
SOURCE is added to the trigger at the time of the connection.
If it is placed in the ESTABLISHED section, each packet that
matches the rule causes the trigger time of the address
(SOURCE or DEST) to be set to the current time.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(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(5)).Example: ACCEPT:info:ftp would include 'ftp ' at the end of
the log prefix generated by the LOGPREFIX setting.SOURCE -
{zone|{all|any}[+][-]}[:interface][:{address-or-range[,address-or-range]...[exclusion]|exclusion|+ipset}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.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.Except when all[+][-] 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.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).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.You may exclude certain hosts from the set already defined
through use of an exclusion (see shorewall-exclusion(5)).Examples:dmz:192.168.2.2Host 192.168.2.2 in the DMZnet:155.186.235.0/24Subnet 155.186.235.0/24 on the Internetloc:192.168.1.1,192.168.1.2Hosts 192.168.1.1 and 192.168.1.2 in the local
zone.loc:~00-A0-C9-15-39-78Host in the local zone with MAC address
00:A0:C9:15:39:78.net:192.0.2.11-192.0.2.17Hosts 192.0.2.11-192.0.2.17 in the net zone.net:!192.0.2.11-192.0.2.17All hosts in the net zone except for
192.0.2.11-192.0.2.17.net:155.186.235.0/24!155.186.235.16/28Subnet 155.186.235.0/24 on the Internet except for
155.186.235.16/28DEST -
{zone|{all|any}[+][-]}[:{interface|address-or-range[,address-or-range]...[exclusion]|exclusion|+ipset}][port[:random]]Location of Server. May be a zone declared in shorewall-zones(5), $FW to indicate the firewall itself, all. all+ or
none.When none is used either in
the SOURCE or DEST column, the rule is ignored.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.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).The zone should be omitted in
DNAT-, REDIRECT- and NONAT rules.If the DEST zone is a bport zone,
then either:the SOURCE must be , orthe SOURCE zone must be
another bport zone associated with the same bridge, orthe SOURCE zone must be an
ipv4 zone that is associated with only the same bridge.
Except when all[+]|[-] 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(5)).Restrictions:1. MAC addresses are not allowed (this is a Netfilter
restriction).2. You may not specify both an interface and an
address.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 you 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.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 modifiy 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
::port.
PROTO (Optional) - {-|tcp:syn|ipp2p|ipp2p:udp|ipp2p:all|protocol-number|protocol-name|all}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.DEST PORT(S) (Optional) -
{-|port-name-number-or-range[,port-name-number-or-range]...}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 numberic type and code separated by a slash (e.g.,
3/4), or a typename. See http://www.shorewall.net/configuration_file_basics.htm#ICMP.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
CLIENT PORT(S) list below:1. There are 15 or less ports listed.2. No port ranges are included or your kernel and iptables
contain extended multiport match support.SOURCE PORT(S) (Optional) -
{-|port-name-number-or-range[,port-name-number-or-range]...}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.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 ORIGINAL DEST 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
DEST PORT(S) list above:1. There are 15 or less ports listed.2. No port ranges are included or your kernel and iptables
contain extended multiport match support.
ORIGINAL DEST (Optional) -
[-|address[,address]...[exclusion]|exclusion]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.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(5).See http://shorewall.net/PortKnocking.html
for an example of using an entry in this column with a user-defined
action rule.RATE LIMIT (Optional) -
[-|[{s|d}:[[name]:]]]rate/{sec|min}[:burst]You may 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 whitespace embedded in
the specification.Example: 10/sec:20When or 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 given, the name shorewallN (where N is a unique integer) is
assumed. Where more than one rule specifies the same name, the
connections counts for the rules are aggregated and the individual
rates apply to the aggregated count.Example: s:ssh:3/min:5USER/GROUP (Optional) -
[!][user-name-or-number][:group-name-or-number][+program-name]This 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).Examples:joeprogram must be run by joe:kidsprogram must be run by a member of the 'kids'
group!:kidsprogram must not be run by a member of the 'kids'
group+upnpdprogram named upnpdThe ability to specify a program name was removed from
Netfilter in kernel version 2.6.14.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)valueValue of the packet or connection mark.maskA mask to be applied to the mark before testing.:CDesignates a connection mark. If omitted, the packet
mark's value is tested.CONNLIMIT - [!]limit[:mask]May be used to limit the number of simultaneous connections
from each individual host 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 host. 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[&timelement...]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.utcTimes are expressed in Greenwich Mean Time.localtzTimes are expressed in Local Civil Time
(default).weekdays=ddd[,ddd]...where ddd is one of
, ,
, ,
, or
monthdays=dd[,dd],...where dd is an ordinal day of
the monthdatestart=yyyy[-mm[-dd[hh[:mm[:ss]]]]]Defines the starting date and time.datestop=yyyy[-mm[-dd[hh[:mm[:ss]]]]]Defines the ending date and time.TRIGGER -
trigger[:[seconds][:[direction]]]Added in Shorewall 4.4.12. An entry in this column restrict
the rule to matching an address that has been previously triggered
by a TRIGGER rule. Normally the SOURCE address is checked but you
can cause the DESTINATION address to be used instead by supplying a
direction of (e.g.,
foo::d). By default, the address must have been triggered within the
last 60 seconds but you can specify a different time using the
seconds option (e.g., foo:30).ExamplesExample 1:Accept SMTP requests from the DMZ to the internet #ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL
# PORT PORT(S) DEST
ACCEPT dmz net tcp smtpExample 2:Forward all ssh and http connection requests from the internet
to local system 192.168.1.3 #ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL
# PORT PORT(S) DEST
DNAT net loc:192.168.1.3 tcp ssh,httpExample 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 DEST SOURCE ORIGINAL RATE
# PORT PORT(S) DEST LIMIT
DNAT net loc:192.168.1.3 tcp http - - 3/sec:10Example 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 DEST SOURCE ORIGINAL
# PORT PORT(S) DEST
REDIRECT loc 3128 tcp www - !192.168.2.2Example 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 DEST SOURCE ORIGINAL
# PORT PORT(S) DEST
DNAT net loc:192.168.1.3 tcp 80 - 130.252.100.69Example 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 DEST SOURCE ORIGINAL
# PORT PORT(S) DEST
ACCEPT net:130.252.100.69,130.252.100.70 $FW \
tcp 22Example 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 DEST SOURCE ORIGINAL
# PORT PORT(S) DEST
DNAT net loc:192.168.1.3:22 tcp 2222Example 8:You want to redirect connection requests to port 80 randomly
to the port range 81-90. #ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL
# PORT PORT(S) DEST
REDIRECT net $FW::81-90:random tcp wwwExample 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(8): #ZONE TYPE OPTIONS
fw firewall
net ipv4
dmz ipv4
loc ipv4shorewall-interfaces(8): #ZONE INTERFACE BROADCAST OPTIONS
net ppp0
loc eth1 detect
dmz eth2 detect
- ppp+ # Addresses are assigned from 192.168.3.0/24shorewall-host(8): #ZONE HOST(S) OPTIONS
loc ppp+:192.168.3.0/24rules: #ACTION SOURCE DEST PROTO DEST
# PORT(S)
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 eth2This 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:Allow a connection from internet host to the firewall's TCP
port 1088 within 30 seconds after the firewall establishes an SSH
connection to that host. #ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL RATE USER/ MARK CONNLIMIT TIME TRIGGER
# PORT(S) PORT(S) DEST LIMIT GROUP
#
# Trigger the incoming connection
#
TRIGGER(port1088:d) fw net tcp 22
#
# Note that the TRIGGER rule must precede the ACCEPT rule; the ACCEPT rule can be omitted if the fw->net policy is ACCEPT
#
ACCEPT fw net tcp 22
#
# Now accept the return connection on port 1088
#
ACCEPT net fw tcp 1088 - - - - - - - port1088:30 FILES/etc/shorewall/rulesSee ALSOshorewall(8), shorewall-accounting(5), shorewall-actions(5),
shorewall-blacklist(5), shorewall-hosts(5), shorewall-interfaces(5),
shorewall-ipsec(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-route_rules(5), shorewall-routestopped(5), shorewall.conf(5),
shorewall-tcclasses(5), shorewall-tcdevices(5), shorewall-tcrules(5),
shorewall-tos(5), shorewall-tunnels(5), shorewall-zones(5)