NAME
firehol.conf - Configuration file for firehol(1)
DESCRIPTION
firehol.conf is the configuration file for firehol(1), which creates an
iptables firewall from the simple rules in this file.
This file is parsed as a bash(1) script, so it’s no problem to use
variables or complex bashisms.
Commands
interface <real interface> <name> [optional rule parameters]
The interface command creates a firewall for protecting the host the
firewall is running, from the given interface. The default interface
policy is drop, so that if no subcommands are given, the firewall
will just drop all incoming and outgoing traffic using this
interface.
Parameters
· real interface
This is the interface name as shown by ip link show. Generally
anything iptables accepts, including the pattern character + (the
plus sign), is valid. The plus sign after some text will match all
interfaces that start with this text. It is allowed to use more
than one interfaces separated by spaces, but all of them should be
given within one quoted argument. Example:
interface "eth0 eth1 ppp0" myname
· name
This is a name for this interface. Generally you should use short
names (10 characters max) without spaces or other symbols. You
should not use the same name more than once in FireHOL primary
commands.
· optional rule parameters
This is a set of rules that allow further restriction of the
traffic that gets matched for this interface. See section Optional
Rules Parameters for more information. Examples:
interface eth0 intranet src 10.0.0.0/16
interface eth0 internet src not "$UNROUTABLE_IPS" (note:
UNROUTABLE_IPS is a variable defined by FireHOL that includes all
IPs that should not be routable by the Internet).
router <name> [optional rule parameters]
The router command creates a firewall for the traffic passing through
the host running the firewall. The only acceptable policy on all
router commands is return and therefore the policy subcommand cannot
be used on routers. This means that no packets are dropped in a
router. Packets not matched by any router command will be dropped at
the end of the firewall.
Parameters
· name
This is a name for this router. The same restrictions of interface
names apply here too.
· optional rule parameters
This is a set of rules that allow further restriction of the
traffic that gets matched for this router. See section Optional
Rules Parameters for more information.
Description
Router statements produce similar iptables commands the interface
statements produce. For each router statement an in_name and an
out_name chain are produced to match the traffic in both directions
of the router.
To match some client or server traffic the administrator has to
specify the input/output interface or the source/destination of the
request. All inface/outface, src/dst optional rule parameters can
be given either on the router statement in which case will be
applied to all subcommands for this router, or on each subcommand
within a router. Both are valid.
For example:
router mylan inface ppp+ outface eth0
server http accept
client smtp accept
The above says: Define a router that matches all requests that
originate from some PPP interface and go out to eth0. There is an
HTTP server in eth0 that client from the PPP interfaces are allowed
to reach. Clients on eth0 are allowed to get SMTP traffic from the
PPP interfaces.
While:
router mylan
server http accept inface ppp+ outface eth0
server smtp accept inface eth0 outface ppp+
The above says: Define a router that matches any kind of forwarded
traffic. For HTTP traffic the clients are on a PPP interface and
the servers on eth0. For SMTP traffic the clients are on a eth0
interface and the servers o a PPP interface.
Please note that in the second example the SMTP traffic is matched
again with a server subcommand, not a client (as in the first
example).
The client subcommand reverses all the optional rules that are
applied indirectly to it. Indirect rule parameters are those that
are inherited from the parent command (router in this case). To
make it simple, for FireHOL a client is: "a server with all the
implicit optional rule parameters reversed".
So, in the first example, the client simply flipped the inface and
outface rules defined at the router and became an SMTP server. In
the second example there is nothing to be flipped, so server and
client are exactly the same.
I suggest to use client subcommands in routers only if you have
inface/outface or src/dst in the router statements. If you are
building routers like the second example, don’t use client, it is
confusing.
Older versions of FireHOL did not allow server and client
subcommands in routers. Only the route subcommand was allowed.
Today, route is just an alias for server and can be used only in
routers, not interfaces.
Any number of router statements can exist. Since the policy is
RETURN on all of them, any traffic not matched by a router will
continue to be checked against the second.
Subcommands
Subcommands must be given within Primary commands.
policy <action>
The policy subcommand defines the default policy for an interface.
This directive accepts all the actions specified in the section
Actions.
The policy of routers cannot be changed and is always RETURN.
protection [reverse] <type>
The protection subcommand sets a number of protection rules on an
interface.
In router configurations, protections are setup on inface.
Parameters
reverse
The reverse keyword will make the protections setup on outface.
type
One of the following values:
strong, full or all
Turns on all known protections
fragments
Drops all packet fragments. Please note that most probably this
rule will never match anything since iptables reconstructs all
packets automatically, before the iptables firewall rules are
processed, when its connection tracker is running.
new-tcp-w/o-syn
Drops all TCP packets that initiate a socket but have no the SYN
bit set.
syn-floods [requests/sec [burst]]
Allows only a certain amount of new TCP connections per second.
The optional two arguments [requests/sec] and [burst] are used by
this rule in order to provide control on the number of
connections to be allowed. The default is 100 connections per
second that can match 50 (it was 4 in v1.38 and before) packets
initially (this is implemented using the limit module of
iptables: see man iptables for more). Note that this rule
applies to all connections attempted regardless of their final
result (rejected, dropped, established, etc). Therefore it might
not be a good idea to set it too low.
icmp-floods [requests/sec [burst]]
Allows only a certain amount of ICMP echo requests per second.
The optional two arguments [requests/sec] and [burst] are used by
this rule in order to provide control on the number of
connections to be allowed. The default is 100 connections per
second that can match 50 (it was 4 in v1.38 and before) packets
initially (this is implemented using the limit module of
iptables: see man iptables for more).
malformed-xmas
Drops all TCP packets that have all TCP flags set.
malformed-null
Drops all TCP packets that have all TCP flags unset.
malformed-bad
Drops all TCP packets that have illegal combinations of TCP flags
set.
server <service> <action> [optional rule parameters]
The server subcommand defines a server of a service. For FireHOL a
server is the destination of a request, and even if this is more
complex for multi-socket services, for FireHOL a server always
accepts requests.
The optional rule parameters given to the parent primary command
(interface or router) are inherited by the server as they have been
given.
This subcommand can be used on both interfaces and routers.
Parameters
service
This is one of the supported service names. The command accepts
more than one services in the same argument if they are separated
by space and quoted as a single argument. Example:
server smtp accept
server "smtp pop3 imap" accept
action
This tells FireHOL what to do with the traffic matching this rule.
FireHOL supports the actions defined in the section Actions.
optional rule parameters
This is a set of rules that allow further restriction of the
traffic that gets matched by this rule. See section Optional Rules
Parameters for more information. Examples:
server smtp accept src 1.2.3.4
server smtp accept log "its mail" src 1.2.3.4
client <service> <action> [optional rule parameters]
The client subcommand defines a client of a service. For FireHOL a
client is the source of a request. FireHOL follows this simple rule
even on multi-socket complex protocols, so that for FireHOL a client
always sends requests. The parameters are exactly the same with the
server subcommand.
The optional rule parameters given to the parent primary command
(interface or router) are inherited by the client, but they are
reversed. For an explanation of this please refer to the
documentation of the router primary command.
This subcommand can be used on both interfaces and routers.
route <service> <action> [optional rule parameters]
The route subcommand is an alias for the server command that can be
used only on routers, not interfaces.
Helper commands
version <number>
The version command states the FireHOL release the configuration file
was created for. In case the configuration file is newer than
FireHOL, FireHOL will deny to run it.
This command is here to allow you or anyone else design and
distribute FireHOL configuration files, while ensuring that the
correct FireHOL version is going to run them.
The FireHOL release is increased every time the format of the
configuration file and the internals of FireHOL are changed.
Since FireHOL v1.67 version is not required to be present in every
configuration file.
iptables <arguments>
The iptables command passes all its arguments to the real iptables
command, during run-time.
You should not use /sbin/iptables directly to alter a FireHOL
firewall in its configurations. If you do, your commands will be run
before FireHOL activates its firewall and while the previous firewall
is still running. Also, since FireHOL will delete all previous
firewall rules in order to activate the new firewall, any changes you
will make, will be deleted too.
Always use the iptables directive to hook iptables commands in a
FireHOL firewall. Nothing else.
masquerade [reverse │ interface] [optional rule parameters]
Masquerading is a special from of SNAT (Source NAT) that changes the
source of requests when they go out and replaces their original
source when replies come in. This way a Linux box can become an
internet router for a LAN of clients having unroutable IP addresses.
Masquerading takes care to re-map IP addresses and ports as required.
Masquerading is "expensive" compared to SNAT because it checks the IP
address of the ougoing interface every time for every packet, and
therefore it is suggested that if you connect to the internet with a
static IP address, to prefer SNAT.
The masquerade helper sets up masquerading on the output of a network
interface (not the interface command, but a real network interface).
If the masquerade command is placed within an interface command, its
network interface[s] will be used.
If the masquerade command is placed within a router command that has
an outface defined, then the outface network interface[s] will be
used.
If placed within a router command but the keyword reverse is
specified and the router command has an inface defined, then the
inface network interface[s] will be used.
If placed outside and before all primary commands, an interface (or
list of space separated interfaces, within double quotes) can be
specified on the masquerade command.
In all cases, masquerade will setup itself on the output of the given
interface[s].
Please note that if masquerade is used within some interface or
router, it does not respect the optional rule parameters given to
this interface or router command. Masquerade uses only its own
optional rule parameters.
inface and outface should not be given as parameters to masquerade
(inface because iptables does not support this in the POSTROUTING
chain, and outface because it will be overwritten by the interface(s)
mentioned above).
Finally, the masquerade helper will turn on FIREHOL_NAT and instruct
the kernel to do packet forwarding (like the router commands do).
Examples:
Before the first interface or router:
masquerade eth0 src 10.0.0.0/8 dst not 10.0.0.0/8
Within an interface rule to masquerade on the output of this
interface:
masquerade
Within a router rule to masquerade on the output of the router’s
inface:
masquerade reverse
transparent_squid <port> <user> [optional rule parameters]
The transparent_squid helper sets up trasparent caching for HTTP
traffic. The squid proxy is assumed to be running on the firewall
host at port port (port defaults to squid), with the credentials of
the local user user (user defaults to squid).
The transparent_squid helper can be used for two kinds of traffic:
· Incoming HTTP traffic
Incoming HTTP traffic, which is either targeted to the firewall
host or passing through the firewall host.
The optional rule parameters can be used to specify which kind of
incoming traffic to be catched (by using inface, src, dst, etc --
outface should not be used here, because the rules generated are
placed before the routing decision and therefore the outgoing
interface is not yet known).
If no optional rule parameters are given, then the transparent
cache will be setup on all network interfaces for all HTTP traffic
(use this with care since you are risking to serve requests from
the internet using your squid).
· Locally HTTP traffic
Locally generated HTTP traffic except traffic generated by
processes running as user user. The optional rule parameters
inface, outface and src are ignored for this type of traffic.
This kind of matching makes it possible to support transparent
caching for WEB browsers running on the firewall host, as far as
they do not run as the user excluded. More than one users can be
specified by space-separating and enclosing them in double quotes.
This rule can be disabled by specifing as user the empty string: ""
Examples:
transparent_squid 3128 squid inface eth0 src 10.0.0.0/8
transparent_squid 8080 "squid privoxy root bin" inface not "ppp+
ipsec+" dst not "a.not.proxied.server"
nat <type> <target> [optional rule parameters]
The nat helper sets up a NAT rule for routed traffic.
The type parameter can be:
to-source
Defines a Source NAT (created in NAT/POSTROUTING).
The target in this case is the source address to be set in packets
matching the optional rule parameters (if no optional rule
parameters, all forwarded traffic will be matched). target accepts
all --to-source values iptables accepts (see iptables -j SNAT
--help). Multiple --to-source values can be given, if separated by
space and quoted as a single argument.
inface should not be used in SNAT, because iptables does provide
this information at this point.
to-destination
Defines a Destination NAT (created in NAT/PREROUTING).
The target in this case is the destination address to be set in
packets matching the optional rule parameters (if no optional rule
parameters, all forwarded traffic will be matched). target accepts
all --to-destination values iptables accepts (see iptables -j DNAT
--help). Multiple --to-destination values can be given, if
separated by space and quoted as a single argument.
outface should not be used in DNAT, because iptables does provide
this information at this point.
redirect-to
Catches traffic comming in and send it to the local machine
(created in NAT/PREROUTING).
The target in this case is a port or a range of ports (XXX-YYY)
that packets matching the rule will be redirected to (if no
optional rule parameters are given, all incomming traffic will be
matched). target accepts all --to-ports values iptables accepts
(see iptables -j REDIRECT --help).
outface should not be used in REDIRECT, because iptables does
provide this information at this point.
Please understand that the optional rule parameters are used only to
limit the traffic to be matched. Consider these examples:
Sends to 1.1.1.1 all traffic comming in or passing trhough the
firewall host:
nat to-destination 1.1.1.1
Redirects to 1.1.1.1 all traffic comming in or passing through, and
going to 2.2.2.2:
nat to-destination 1.1.1.1 dst 2.2.2.2
Redirects to 1.1.1.1 all TCP traffic comming in or passing through
and going to 2.2.2.2:
nat to-destination 1.1.1.1 proto tcp dst 2.2.2.2
Redirects to 1.1.1.1 all traffic comming in or passing through and
going to 2.2.2.2 to port tcp/25:
nat to-destination 1.1.1.1 proto tcp dport 25 dst 2.2.2.2
More examples:
nat to-source 1.1.1.1 outface eth0 src 2.2.2.2 dst 3.3.3.3
nat to-destination 4.4.4.4 inface eth0 src 5.5.5.5 dst 6.6.6.6
nat redirect-to 8080 inface eth0 src 2.2.2.0/24 proto tcp dport 80
snat [to] <target> [optional rule parameters]
The snat helper sets up a Source NAT rule for routed traffic, by
calling nat to-source target [optional rule parameters]
See the nat helper.
Example:
snat to 1.1.1.1 outface eth0 src 2.2.2.2 dst 3.3.3.3
dnat [to] <target> [optional rule parameters]
The dnat helper sets up a Destination NAT rule for routed traffic, by
calling nat to-destination target [optional rule parameters]
See the nat helper.
Example:
dnat to 1.1.1.1 inface eth0 src 2.2.2.2 dst 3.3.3.3
redirect [to] <target> [optional rule parameters]
The redirect helper catches all incomming traffic matching the
optional rule parameters given and redirects it to ports on the local
host, by calling nat redirect-to target [optional rule parameters]
See the nat helper.
Example:
nat redirect-to 8080 inface eth0 src 2.2.2.0/24 proto tcp dport 80
Actions
Actions are the actions to be taken on services and traffic described
by other commands and functions. Please note that normally, FireHOL
will pass-through to the generated iptables statements all the possible
actions iptables accepts, but only the ones defined here can be used
with lower case letters and currently it will be impossible to pass
arguments to some unknown action. Also, keep in mind that the iptables
action LOG is a FireHOL optional rule parameter (see log and loglimit)
that can be defined together with one of the following actions and
FireHOL will actually produce multiple iptables statements to achieve
both the logging and the action.
accept
accept allows the traffic matching the rules to reach its
destination.
Example:
server smtp accept, to allow SMTP requests and their replies to
flow.
reject [with message]
reject discards the matching traffic but sends a rejecting message
back to the sender.
with is used to offer control on the message to be returned to the
sender. with accepts all the arguments the --reject-with iptables
expression accepts. For an updated list of these messages type
iptables -j REJECT --help.
Examples:
policy reject with host-unreach
server ident reject with tcp-reset
UNMATCHED_INPUT_POLICY="reject with host-prohib"
drop
drop silently discards the matching traffic. The fact that the
traffic is silently discarded makes the sender timeout in order to
conclude that it is not possible to use the wanted service.
Example:
server smtp drop, to silently discard SMTP requests and their
replies.
deny
deny is just an alias for drop, made for those who are used to
ipchains terminology.
Example:
server smtp deny, to silently discard SMTP requests and their
replies.
return
return will return the flow of processing to the parent of the
current command. Currently, it has meaning to specify the action
return only as a policy to some interface.
Example:
policy return
Traffic not matched by any rule within an interface continues
traveling through the firewall and is possibly matched by other
interfaces bellow.
mirror
mirror will return the traffic to the wanted port, back to the
sending host. Use this with care, and only if you understand what you
doing. Keep also in mind that FireHOL will apply this action to both
requests and replies comming in or passing through, and will replace
it with REJECT for traffic generated by the local host.
redirect [to-port port]
redirect is used internally by FireHOL Helper Commands to redirect
traffic to ports on the local host. Unless you are a developer, you
will never need to use this directly.
Optional Rule Parameters
Optional rule parameters are accepted by many commands to narrow the
match they do by default. The parameters described bellow are all that
FireHOL supports. You should check the documentation of each command to
find which parameters should not be used with it. Normally, all
FireHOL commands are designed so that if you specify a parameters that
is also used internally, the internal one will overwrite the one given
in the configuration file. In such a case, FireHOL will present you a
warning with the old and the new value.
Not all parameters should be used in all cases. For example sport and
dport should not be used in normal server and client commands since
such ports are internally defined by the services themselves. In any
case, FireHOL will complain about optional rule parameters that should
not be used in certain commands.
src [not] <host>
src defines the source IP address of the REQUEST. If src is defined
on a server statement it matches the source of the request which is
the remote host, while if it is defined on a client statement it
matches again the source of the request, but this time it is the
local host. Focus on the REQUEST!!! Forget the reply.
Parameters
not
Optional argument that reverses the match. When defined, the rule
will match all hosts except the ones defined. Example:
server smtp accept src not 1.2.3.4
host
An IP address, a hostname, or a subnet. Multiple hosts/networks can
be defined if separated by space and quoted as a single argument.
Examples:
server smtp accept src 1.2.3.4
server smtp accept src not "1.2.3.0/24 5.6.7.8
badhost.example.com"
dst [not] <host>
dst defines the destination of the REQUEST. If dst is defined on a
server statement it matches the destination of the request which is
the local host, while if it is defined on a client statement it
matches again the destination of the request, but this time it is the
remote host. Focus on the REQUEST!!! Forget the reply.
dst accepts the same parameters as src.
inface [not] <interface>
inface defines the interface the REQUEST is received via. inface
cannot be used in interface commands.
Parameters
not
An optional argument that reverses the match. When defined, the
rule will match all interfaces except the ones defined. Example:
server smtp accept inface not eth0
interface
if an interface name in the same format the interface command
accepts. Multiple interfaces can be defined if separated by space
and quoted as a single argument. Examples:
server smtp accept inface not eth0
server smtp accept inface not "eth0 eth1"
outface [not] <interface>
outface defines the interface the REQUEST is send via. outface cannot
be used in interface commands.
outface accepts the same parameters as inface.
custom <parameters>
custom passes its arguments to the generated iptables commands.
It is required to quote all the parameters given to custom. If the
parameters include a space character between some text that is
required to be given to iptables as one argument, it is required to
escape another set of quotes in order. Another way is to use double
quotes externally and single quotes internally.
Examples:
server smtp accept custom "--some-iptables-option and_its_value"
server smtp accept custom "--some-iptables-option ’one_value another_value’
log "<some text>" [level a_level]
log will log the matching packets to syslog. Note that this is not an
action (in iptables it is). FireHOL will actually produce multiple
iptables commands to accomplish both the action for the rule and the
logging. You can control how logging works, by altering the variables
FIREHOL_LOG_OPTIONS and FIREHOL_LOG_LEVEL. You can also change the
level of just one rule by using the level argument of the log
parameter.
FireHOL logs traffic, exactly the same way iptables does. Many users
have complained about packet logs appearing at their console. To
avoid this you will have to:
· setup klogd to log only more important traffic
· change FIREHOL_LOG_LEVEL to log at a not so important log-level
Actually klogd’s -c option and iptables’ --log-level option are the
same thing (iptables accepts also the numeric values klogd accepts).
If iptables logs at a higher priority than klogd is configured to
use, then your packets will appear in the console too.
loglimit "<some text>"
loglimit is the same with log but limits the frequency of logging
according to the setting of FIREHOL_LOG_FREQUENCY and
FIREHOL_LOG_BURST.
proto [not] <protocol>
proto sets the required protocol for the traffic. This command
accepts anything iptables accepts as protocols.
limit <frequency> <burst>
limit will limit the match in both directions of the traffic (request
and reply). This is used internally by FireHOL and its effects has
not been tested in the high level configuration file directives.
sport <port>
sport defines the source port of a request. It accepts port names,
port numbers, port ranges (FROM:TO) and multiple ports (or ranges)
seperated by spaces and quoted as a single argument. This parameter
should not be used in normal services definitions (client and server
commands) or interface and router definitions, unless you really
understand what you are doing.
dport <port>
dport defines the destination port of a request. It accepts port
names, port numbers, port ranges (FROM:TO) and multiple ports (or
ranges) seperated by spaces and quoted as a single argument. This
parameter should not be used in normal services definitions (client
and server commands) or interface and router definitions, unless you
really understand what you are doing.
uid [not] <user> =head2 user [not] <user>
uid or user define the operating system user sending this traffic.
The parameter can be a username, a user number or a list of these
two, seperated by spaces and quoted as a single argument.
This parameter can be used only in services (client and server
commands) defined within interfaces, not routers. FireHOL is "smart"
enough to apply this parameter only to traffic send by the localhost,
i.e. the replies of servers and requests of clients. It is not
possible, and FireHOL will simply ignore this parameter, on traffic
coming in or passign through the firewall host.
Example 1:
client "pop3 imap" accept user not "user1 user2 user3" dst mymailer.example.com
The above will allow local users except user1, user2 and user3 to use
POP3 and IMAP services on mymailer.example.com. You can use this, for
example, to allow only a few of the local users use the fetchmail
program to fetch their mail from the mail server.
Example 2:
server http accept user apache
The above will allow all HTTP to reach the local http server, but
only if the web server is running as user apache the replies will be
send back to the HTTP client.
gid <group> =head2 group <group>
gid or group define the operating system user group sending this
traffic. The parameter can be a group name, a group number or a list
of these two, seperated by spaces and quoted as a single argument.
This parameter can be used only in services (client and server
commands) defined within interfaces, not routers. FireHOL is "smart"
enough to apply this parameter only to traffic send by the localhost,
i.e. the replies of servers and requests of clients. It is not
possible, and FireHOL will simply ignore this parameter, on traffic
coming in or passing through the firewall host.
pid <process> =head2 process <process>
pid or process define the operating system process ID (or PID)
sending this traffic. The parameter can be a PID or a list of PIDs,
seperated by spaces and quoted as a single argument.
This parameter can be used only in services (client and server
commands) defined within interfaces, not routers. FireHOL is "smart"
enough to apply this parameter only to traffic send by the localhost,
i.e. the replies of servers and requests of clients. It is not
possible, and FireHOL will simply ignore this parameter, on traffic
coming in or passign through the firewall host.
sid <session> =head2 session <session>
sid or session define the operating system session ID of the process
sending this traffic (The session ID of a process is the process
group ID of the session leader). The parameter can be a list of such
IDs, seperated by spaces and quoted as a single argument.
This parameter can be used only in services (client and server
commands) defined within interfaces, not routers. FireHOL is "smart"
enough to apply this parameter only to traffic send by the localhost,
i.e. the replies of servers and requests of clients. It is not
possible, and FireHOL will simply ignore this parameter, on traffic
coming in or passign through the firewall host.
Variables that control FireHOL
DEFAULT_INTERFACE_POLICY
DEFAULT_INTERFACE_POLICY controls the default action to be taken on
traffic not matched by any rule within an interface. Actually, this
is a global setting for what policy does for an interface.
All packets that reach the end of an interface are logged only if the
action is not return or accept. You can control the frequency of this
logging by altering the frequency loglimit uses.
Default: DEFAULT_INTERFACE_POLICY="DROP"
Example: DEFAULT_INTERFACE_POLICY="REJECT"
UNMATCHED_INPUT_POLICY
UNMATCHED_OUTPUT_POLICY
UNMATCHED_FORWARD_POLICY
UNMATCHED_INPUT_POLICY controls the default action to be taken for
incoming traffic not matched by any interface command.
UNMATCHED_OUTPUT_POLICY controls the default action to be taken for
outgoing traffic not matched by any interface command.
UNMATCHED_FORWARD_POLICY controls the default action to be taken for
forwarded traffic not matched by any router command.
All variables accept all the Actions FireHOL supports.
All packets that reach the end of firewall in all three chains are
logged (always, regardless of these settings). You can control the
frequency of this logging by altering the frequency loglimit uses.
Default: UNMATCHED_INPUT_POLICY="DROP"
Default: UNMATCHED_OUTPUT_POLICY="DROP"
Default: UNMATCHED_FORWARD_POLICY="DROP"
Example: UNMATCHED_INPUT_POLICY="REJECT"
Example: UNMATCHED_OUTPUT_POLICY="REJECT"
Example: UNMATCHED_FORWARD_POLICY="REJECT"
FIREHOL_LOG_LEVEL =head2 FIREHOL_LOG_OPTIONS =head2
FIREHOL_LOG_FREQUENCY =head2 FIREHOL_LOG_BURST
FIREHOL_LOG_LEVEL controls the level at which iptables will log
things to the syslog. For a description of the possible values
supported and for per-rule control of log level, see the log optional
rule parameter.
FIREHOL_LOG_OPTIONS controls the way iptables will log things to the
syslog. The value of this variable is passed as is to iptables, so
use exact iptables parameters.
FIREHOL_LOG_FREQUENCY and FIREHOL_LOG_BURST (added in v1.39 of
FireHOL) control the frequency at each each logging rule will write
packets to the syslog. FIREHOL_LOG_FREQUENCY is set to the maximum
average frequency and FIREHOL_LOG_BURST specifies the maximum initial
number of packets to match.
Default: FIREHOL_LOG_OPTIONS="--log-level warning"
Default: FIREHOL_LOG_FREQUENCY="1/second"
Default: FIREHOL_LOG_BURST="5"
Example: FIREHOL_LOG_OPTIONS="--log-level info --log-tcp-options --log-ip-options"
Example: FIREHOL_LOG_FREQUENCY="30/minute"
Example: FIREHOL_LOG_BURST="2"
To see the available iptables log options, run "/sbin/iptables -j LOG
--help" To see what iptables accepts as frequencies and bursts, run
"/sbin/iptables -m limit --help"
You can also check man iptables.
DEFAULT_CLIENT_PORTS
DEFAULT_CLIENT_PORTS controls the port range to be used when a remote
client is specified. For localhost clients, FireHOL finds the exact
client ports by querying the kernel options.
Default: 1000:65535
Example: DEFAULT_CLIENT_PORTS="0:65535"
FIREHOL_NAT
If FIREHOL_NAT is set to 1, FireHOL will load NAT kernel modules for
those services that they are require such. FireHOL sets this to 1
automatically if you use the Helper Commands that do NAT.
Default: FIREHOL_NAT="0"
Example: FIREHOL_NAT="1"
FIREHOL_AUTOSAVE
FIREHOL_AUTOSAVE controls the file that will be created when FireHOL
is called with the save command line argument. If this variable is
empty (the default), FireHOL will try to detect where to save the
file. Currently, the RedHat way (/etc/sysconfig/iptables) and the
Debian way (/var/lib/iptables/autosave) are automatically detected
(in the order given here) based on the existance of the directory
this file should be created in.
Default: FIREHOL_AUTOSAVE="" Example:
FIREHOL_AUTOSAVE="/tmp/firehol-saved.txt"
Variables that FireHOL offers
RESERVED_IPS
This variable includes all the IP addresses defined as IANA -
Reserved by IANA.
Example: interface eth0 internet src not "${RESERVED_IPS}"
PRIVATE_IPS
This variable includes all the IP addresses defined as Private or
Test by RFC 3330.
Example: interface eth0 internet src not "${PRIVATE_IPS}"
UNROUTABLE_IPS
This variable is both RESERVED_IPS and PRIVATE_IPS together. I
suggest to use this variable on interfaces and routers accepting
Internet traffic.
Example: interface eth0 internet src not "${UNROUTABLE_IPS}"
FILES
/etc/firehol/firehol.conf
AUTHOR
firehol written by Costa Tsaousis <costa@tsaousis.gr>.
Man page written by Marc Brockschmidt <<marc@marcbrockschmidt.de>.
SEE ALSO
firehol(1), iptables(8), bash(1)
2003-06-09