Ubuntu Manpage: firehol.conf - Configuration file for firehol(1)

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 specifying 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 incoming 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 incoming 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) separated 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) separated 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, separated 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, separated by spaces and quoted as a single argument.

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, separated by spaces and quoted as a single argument.

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, separated by spaces and quoted as a single argument.

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>.

NAME

DESCRIPTION

Commands

Subcommands

Helper commands

Actions

Optional Rule Parameters

Variables that control FireHOL

Variables that FireHOL offers

FILES

AUTHOR

SEE ALSO