Ubuntu Manpage: sanewall.conf - Sanewall configuration file

name
description
variables available
adding services
definitions
subcommands
helper commands
configuration helper commands
see also
author
copyright
notes

NAME

       sanewall.conf - Sanewall configuration file

DESCRIPTION

/etc/sanewall/sanewall.conf is the default configuration file for Sanewall program: sanewall(1). It
defines the stateful firewall that will be produced.

A configuration file starts with an optional version indicator which looks like this:

version 5

See version config helper: sanewall-version(5) for full details.

A configuration file contains one or more interface definitions, which look like this:

interface eth0 lan
client all accept # This host can access any remote service
server ssh accept # Remote hosts can access SSH on local server
# ...

The above definition has name "lan" and specifies a network interface (eth0). A definition may contain
zero or more subcommands. See interface definition: sanewall-interface(5) for full details.

A configuration file contains one or more router definitions, which look like this:

DMZ_IF=eth0
WAN_IF=eth1
router wan2dmz inface ${WAN_IF} outface ${DMZ_IF}
route http accept # Hosts on WAN may access HTTP on hosts in DMZ
server ssh accept # Hosts on WAN may access SSH on hosts in DMZ
client pop3 accept # Hosts in DMZ may access POP3 on hosts on WAN
# ...

The above definition has name "wan2dmz" and specifies incoming and outgoing network interfaces (eth1 and
eth0) using variables. A definition may contain zero or more subcommands. Note that a router is not
required to specify network interfaces to operate on. See router definition: sanewall-router(5) for full
details.

It is simple to add extra service definitions which can then be used in the same way as those provided as
standard. See the section called “ADDING SERVICES”.

The configuration file is parsed as a bash(1) script, allowing you to set up and use variables, flow
control and external commands.

Special control variables: sanewall-variables(5) may be set up and used outside of any definition as can
the functions in the section called “CONFIGURATION HELPER COMMANDS” and the section called “HELPER
COMMANDS”.

VARIABLES AVAILABLE

       The following variables are made available in the Sanewall configuration file and can be accessed as
       ${VARIABLE}.

       UNROUTABLE_IPS
           This variable includes the IPs from both PRIVATE_IPS and RESERVED_IPS. It is useful to restrict
           traffic on interfaces and routers accepting Internet traffic, for example:

               interface eth0 internet src not "${UNROUTABLE_IPS}"

       PRIVATE_IPS
           This variable includes all the IP addresses defined as Private or Test by RFC 3330[1].

           You can override the default values by creating a file called /etc/sanewall/PRIVATE_IPS.

       RESERVED_IPS
           This variable includes all the IP addresses defined by IANA[2] as reserved.

           You can override the default values by creating a file called /etc/sanewall/RESERVED_IPS.

           Now that IPv4 address space has all been allocated there is very little reason that this value will
           need to change in future.

       MULTICAST_IPS
           This variable includes all the IP addresses defined as Multicast by RFC 3330[1].

           You can override the default values by creating a file called /etc/sanewall/MULTICAST_IPS.

ADDING SERVICES

To define new services you add the appropriate lines before using them later in the configuration file.

The following are required:

server_myservice_ports="proto/sports"
client_myservice_ports="cports"

proto is anything iptables(8) accepts e.g. "tcp", "udp", "icmp", including numeric protocol values.

sports is the ports the server is listening at. It is a space-separated list of port numbers, names and
ranges (from:to). The keyword any will match any server port.

cports is the ports the client may use to initiate a connection. It is a space-separated list of port
numbers, names and ranges (from:to). The keyword any will match any client port. The keyword default will
match default client ports. For the local machine (e.g. a client within an interface) it resolves to
sysctl variable net.ipv4.ip_local_port_range (or /proc/sys/net/ipv4/ip_local_port_range). For a remote
machine (e.g. a client within an interface or anything in a router) it resolves to the variable
DEFAULT_CLIENT_PORTS (see control variables: sanewall-variables(5)).

The following are optional:

require_myservice_modules="modules"
require_myservice_nat_modules="nat-modules"

The named kernel modules will be loaded when the definition is used. The NAT modules will only be loaded
if SANEWALL_NAT is non-zero (see control variables: sanewall-variables(5)).

For example, for a service named daftnet that listens at two ports, port 1234 TCP and 1234 UDP where the
expected client ports are the default random ports a system may choose, plus the same port numbers the
server listens at, with further dynamic ports requiring kernel modules to be loaded:

version 5

server_daftnet_ports="tcp/1234 udp/1234"
client_daftnet_ports="default 1234"
require_daftnet_modules="ip_conntrack_daftnet"
require_daftnet_nat_modules="ip_nat_daftnet"

interface eth0 lan0
server daftnet accept

interface eth1 lan1
client daftnet reject

router lan2lan inface eth0 outface eth1
route daftnet accept

Where multiple ports are provides (as per the example), Sanewall simply determines all of the
combinations of client and server ports and generates multiple iptables statements to match them.

To create more complex rules, or stateless rules, you will need to create a bash function prefixed rules_
e.g. rules_myservice. The best reference is the many such functions in the main sanewall executable.

When adding a service which uses modules, or via a custom function, you may also wish to include the
following:

ALL_SHOULD_ALSO_RUN="${ALL_SHOULD_ALSO_RUN} myservice"

which will ensure your service is set-up correctly as part of the all service.

Note
To allow definitions to be shared you can instead create files and install them in the
/etc/sanewall/services directory with a .conf extension.

The first line must read:

FHVER 1:213

1 is the service definition API version. It will be changed if the API is ever modified. 213 refers
to a FireHOL version and is retained for compatibility.

Sanewall will refuse to run if the API version does not match the expected one. The minor number is
ignored.

At version 1:213, the API and therefore service definitions are compatible with FireHOL.

DEFINITIONS

           interface definition: sanewall-interface(5)
           router definition: sanewall-router(5)

SUBCOMMANDS

           policy command: sanewall-policy(5)
           protection command: sanewall-protection(5)
           server, route commands: sanewall-server(5)
           client command: sanewall-client(5)
           group command: sanewall-group(5)

HELPER COMMANDS

       These helpers can be used in interface and router definitions as well as before them.
           iptables helper: sanewall-iptables(5)
           masquerade helper: sanewall-masquerade(5)

       This helper can be used in router definitions as well as before any router or interface.
           tcpmss helper: sanewall-tcpmss(5)

CONFIGURATION HELPER COMMANDS

       These helpers should only be used outside of interface and router definitions (i.e. before the first
       interface is defined).
           version config helper: sanewall-version(5)
           action config helper: sanewall-action(5)
           blacklist config helper: sanewall-blacklist(5)
           classify config helper: sanewall-classify(5)
           connmark config helper: sanewall-connmark(5)
           dscp config helper: sanewall-dscp(5)
           mac config helper: sanewall-mac(5)
           mark config helper: sanewall-mark(5)
           nat, snat, dnat, redirect config helpers: sanewall-nat(5)
           transparent_proxy, transparent_squid helpers: sanewall-transparent_proxy(5)
           tos config helper: sanewall-tos(5)
           tosfix config helper: sanewall-tosfix(5)

AUTHOR

       Sanewall Team

COPYRIGHT

       Copyright © 2012, 2013 Phil Whineray <phil@sanewall.org>

NOTES

        1. RFC 3330
           https://tools.ietf.org/html/rfc3330

        2. IANA
           http://www.iana.org/

        3. Sanewall Online Documentation
           http://www.sanewall.org/