Ubuntu Manpage: providers - Shorewall Providers file

NAME

       providers - Shorewall Providers file

SYNOPSIS

       /etc/shorewall/providers

DESCRIPTION

This file is used to define additional routing tables. You will want to define an
additional table if:

• You have connections to more than one ISP or multiple connections to the same ISP

• You run Squid as a transparent proxy on a host other than the firewall.

• You have other requirements for policy routing.

Each entry in the file defines a single routing table.

If you wish to omit a column entry but want to include an entry in the next column, use
"-" for the omitted entry.

The columns in the file are as follows.

NAME - name
The provider name. Must be a valid shell variable name. The names 'local', 'main',
'default' and 'unspec' are reserved and may not be used as provider names.

NUMBER - number
The provider number -- a number between 1 and 15. Each provider must be assigned a
unique value.

MARK (Optional) - value
A FWMARK value used in your shorewall-mangle(5)[1] file to direct packets to this
provider.

If PROVIDER_OFFSET is non-zero in shorewall.conf(5)[2], then the value must be a
multiple of 2^^PROVIDER_OFFSET. In all cases, the number of significant bits may not
exceed PROVIDER_OFFSET + PROVIDER_BITS.

DUPLICATE - routing-table-name
The name of an existing table to duplicate to create this routing table. May be main
or the name of a previously listed provider. You may select only certain entries from
the table to copy by using the COPY column below. This column should contain a dash
("-') when USE_DEFAULT_RT=Yes in shorewall.conf(5)[2].

INTERFACE - interface[:address]
The name of the network interface to the provider. Must be listed in
shorewall-interfaces(5)[3]. In general, that interface should not have the proxyarp or
proxyndp option specified unless loose is given in the OPTIONS column of this entry.

Where more than one provider is serviced through a single interface, the interface
must be followed by a colon and the IP address of the interface that is supplied by
the associated provider.

GATEWAY - {-|address[,mac]|detect|none}
The IP address of the provider's gateway router. Beginning with Shorewall 4.6.2, you
may also specify the MAC address of the gateway when there are multiple providers
serviced through the same interface. When the MAC is not specified, Shorewall will
detect the MAC during firewall start or restart.

You can enter detect here and Shorewall will attempt to detect the gateway
automatically.

Beginning with Shorewall 5.0.6, you may also enter none. This causes creation of a
routing table with no default route in it.

For PPP devices, you may omit this column.

OPTIONS (Optional) - [-|option[,option]...]
A comma-separated list selected from the following. The order of the options is not
significant but the list may contain no embedded white-space.

autosrc
Added in Shorewall 4.5.17. Causes a host route to the provider's gateway router to
be added to the provider's routing table. This is the default behavior unless
overridden by a following noautosrc option.

track
If specified, inbound connections on this interface are to be tracked so that
responses may be routed back out this same interface.

You want to specify track if internet hosts will be connecting to local servers
through this provider.

Beginning with Shorewall 4.4.3, track defaults to the setting of the
TRACK_PROVIDERS option in shorewall.conf[2] (5). If you set TRACK_PROVIDERS=Yes
and want to override that setting for an individual provider, then specify notrack
(see below).

balance[=weight]
The providers that have balance specified will get outbound traffic load-balanced
among them. By default, all interfaces with balance specified will have the same
weight (1). You can change the weight of an interface by specifying balance=weight
where weight is the weight of the route out of this interface.

Prior to Shorewall 5.1.1, when USE_DEFAULT_RT=Yes, balance=1 is assumed unless the
fallback, loose, load or tproxy option is specified. Beginning with Shorewall
5.1.1, when BALANCE_PROVIDERS=Yes, balance=1 is assumed unless the fallback,
loose, load or tproxy option is specified.I

Caution
In IPV6, the balance option does not cause balanced default routes to be
created; it rather causes a sequence of default routes with different metrics
to be created.

loose
Shorewall normally adds a routing rule for each IP address on an interface which
forces traffic whose source is that IP address to be sent using the routing table
for that interface. Setting loose prevents creation of such rules on this
interface.

load=probability
Added in Shorewall 4.6.0. This option provides an alternative method of load
balancing based on probabilities. Providers to be balanced are given a probability
(a number 0 > n >= 1) with up to 8 digits to the right of the decimal point.
Beginning with Shorewall 4.6.10, a warning is issued if the sum of the
probabilities is not 1.00000000.

noautosrc
Added in Shorewall 4.5.17. Prevents the addition of a host route to the provider's
gateway router from being added to the provider's routing table. This option must
be used with caution as it can cause start and restart failures.

notrack
Added in Shorewall 4.4.3. When specified, turns off track.

optional (deprecated for use with providers that do not share an interface)
If the interface named in the INTERFACE column is not up and configured with an
IPv4 address then ignore this provider. If not specified, the value of the
optional option for the INTERFACE in shorewall-interfaces(5)[3] is assumed. Use of
that option is preferred to this one, unless an address is provider in the
INTERFACE column.

primary
Added in Shorewall 4.6.6, primary is equivalent to balance=1 and is preferred when
the remaining providers specify fallback or tproxy.

src=source-address
Specifies the source address to use when routing to this provider and none is
known (the local client has bound to the 0 address). May not be specified when an
address is given in the INTERFACE column. If this option is not used, Shorewall
substitutes the primary IP address on the interface named in the INTERFACE column.

mtu=number
Specifies the MTU when forwarding through this provider. If not given, the MTU of
the interface named in the INTERFACE column is assumed.

fallback[=weight]
Indicates that a default route through the provider should be added to the default
routing table (table 253). If a weight is given, a balanced route is added with
the weight of this provider equal to the specified weight. If the option is given
without a weight, an separate default route is added through the provider's
gateway; the route has a metric equal to the provider's NUMBER.

Prior to Shorewall 4.4.24, the option is ignored with a warning message if
USE_DEFAULT_RT=Yes in shorewall.conf.

Caution
In IPV6, specifying the fallback option on multiple providers does not cause
balanced fallback routes to be created; it rather causes a sequence of
fallback routes with different metrics to be created.

tproxy
Added in Shorewall 4.5.4. Used for supporting the TPROXY action in
shorewall-mangle(5). See http://www.shorewall.net/Shorewall_Squid_Usage.html[4].
When specified, the MARK, DUPLICATE and GATEWAY columns should be empty, INTERFACE
should be set to 'lo' and tproxy should be the only OPTION. Only one tproxy
provider is allowed.

hostroute
Added in Shorewall 4.5.21. This is the default behavior that results in a host
route to the defined GATEWAY being inserted into the main routing table and into
the provider's routing table. hostroute is required for older distributions but
nohostroute (below) is appropriate for recent distributions. hostroute may
interfere with Zebra's ability to add routes on some distributions such as Debian
7.

nohostroute
Added in Shorewall 4.5.21. nohostroute inhibits addition of a host route to the
defined GATEWAY being inserted into the main routing table and into the provider's
routing table. nohostroute is not appropriate for older distributions but is
appropriate for recent distributions. nohostroute allows Zebra's to correctly add
routes on some distributions such as Debian 7.

persistent
Added in Shorewall 5.0.2 and alters the behavior of the disable command:

• The provider's routing table still contains the apprioriate default route.

• Unless the noautosrc option is specified, routing rules are generated to route
traffic from the interfaces address(es) out of the provider's routing table.

• Persistent routing rules in shorewall-rtrules(5)[5] are present.

Note
The generated script will attempt to reenable a disabled persistent provider
during execution of the start, restart and reload commands. When persistent is
not specified, only the enable and reenable commands can reenable the
provider.

Important
RESTORE_DEFAULT_OPTION=Yes in shorewall[6].conf is not recommended when the
persistent option is used, as restoring default routes to the main routing
table can prevent link status monitors such as foolsm from correctly detecting
non-working providers.

COPY - [{none|interface[,interface]...}]
A comma-separated list of other interfaces on your firewall. Wildcards specified using
an asterisk ("*") are permitted (e.g., tun* ). Usually used only when DUPLICATE is
main. Only copy routes through INTERFACE and through interfaces listed here. If you
only wish to copy routes through INTERFACE, enter none in this column.

Beginning with Shorewall 4.5.17, blackhole, unreachable and prohibit routes are no
longer copied by default but may be copied by including blackhole,unreachable and
prohibit respectively in the COPY list.

EXAMPLES

       IPv4 Example 1:
           You run squid in your DMZ on IP address 192.168.2.99. Your DMZ interface is eth2

                       #NAME   NUMBER  MARK DUPLICATE  INTERFACE GATEWAY       OPTIONS
                       Squid   1       1    -          eth2      192.168.2.99  -

       IPv4 Example 2:
           eth0 connects to ISP 1. The IP address of eth0 is 206.124.146.176 and the ISP's
           gateway router has IP address 206.124.146.254.

           eth1 connects to ISP 2. The IP address of eth1 is 130.252.99.27 and the ISP's gateway
           router has IP address 130.252.99.254.

           eth2 connects to a local network.

                       #NAME NUMBER MARK DUPLICATE INTERFACE GATEWAY          OPTIONS            COPY
                       ISP1  1       1    main      eth0      206.124.146.254 track,balance      eth2
                       ISP2  2       2    main      eth1      130.252.99.254  track,balance      eth2

       IPv6 Example 1:
           You run squid in your DMZ on IP address 2002:ce7c:92b4:1::2. Your DMZ interface is
           eth2

                       #NAME   NUMBER  MARK DUPLICATE  INTERFACE GATEWAY              OPTIONS
                       Squid   1       1    -          eth2      2002:ce7c:92b4:1::2  -

       IPv6 Example 2:
           eth0 connects to ISP 1. The ISP's gateway router has IP address 2001:ce7c:92b4:1::2.

           eth1 connects to ISP 2. The ISP's gateway router has IP address 2001:d64c:83c9:12::8b.

           eth2 connects to a local network.

                       #NAME NUMBER MARK DUPLICATE INTERFACE GATEWAY               OPTIONS    COPY
                       ISP1  1       1    main      eth0     2001:ce7c:92b4:1::2   track      eth2
                       ISP2  2       2    main      eth1     2001:d64c:83c9:12::8b track      eth2

FILES

       /etc/shorewall/providers

       /etc/shorewall6/providers

NOTES