Beginning with Shorewall 4.4.15, the file may contain entries for both IPv4 and IPv6. By default, all rules apply to IPv4 but that can be changed by inserting a line as follows:

IPV4

Following entries apply to IPv4.

IPV6

Following entries apply to IPv6

ALL

Following entries apply to both IPv4 and IPv6. Each entry is processed twice; once for IPv4 and once for IPv6.

The columns in the file are as follows (where the column name is followed by a different name in parentheses, the different name is used in the alternate specification syntax).

CLASS - interface:class

The name or number of an interface defined in m[blue]shorewall-tcdevicesm[][1](5) followed by a class number defined for that interface in m[blue]shorewall-tcclassesm[][2](5).

SOURCE - {-|address|+ipset}

Source of the packet. May be a host or network address. DNS names are not allowed. Beginning with Shorewall 4.6.0, an ipset name (prefixed with '+') may be used if your kernel and ip6tables have the Basic Ematch capability and you set BASIC_FILTERS=Yes in m[blue]shorewall.conf (5)m[][3]. The ipset name may optionally be followed by a number or a comma separated list of src and/or dst enclosed in square brackets ([...]). See m[blue]shorewall-ipsets(5)m[][4] for details.

DEST - {-|address|+ipset}

Destination of the packet. May be a host or network address. DNS names are not allowed. Beginning with Shorewall 4.6.0, an ipset name (prefixed with '+') may be used if your kernel and ip6tables have the Basic Ematch capability and you set BASIC_FILTERS=Yes in m[blue]shorewall.conf (5)m[][3]. The ipset name may optionally be followed by a number or a comma separated list of src and/or dst enclosed in square brackets ([...]). See m[blue]shorewall-ipsets(5)m[][4] for details.

You may exclude certain hosts from the set already defined through use of an exclusion (see m[blue]shorewall-exclusionm[][5](5)).

PROTO - {-|{protocol-number|protocol-name|all}[,...]}

Protocol.

Beginning with Shorewall 4.5.12, this column can accept a comma-separated list of protocols.

DPORT - [-|port-name-or-number]

Optional destination Ports. A Port name (from services(5)) or a port number; if the protocol is icmp, this column is interpreted as the destination icmp-type(s).

This column was previously labelled DEST PORT(S).

SPORT - [-|port-name-or-number]

Optional source port.

This column was previously labelled SOURCE PORT(S).

TOS (Optional) - [-|tos]

Specifies the value of the TOS field. The tos value can be any of the following:

• tos-minimize-delay

• tos-maximize-throughput

• tos-maximize-reliability

• tos-minimize-cost

• tos-normal-service

• hex-number

• hex-number/hex-number

The hex-numbers must be exactly two digits (e.g., 0x04)x.

LENGTH - [-|number]

Optional - Must be a power of 2 between 32 and 8192 inclusive. Packets with a total length that is strictly less than the specified number will match the rule.

PRIORITY - [-|priority]

Added in Shorewall 4.5.8. Specifies the rule priority. The priority value must be > 0 and <= 65535.

When a priority is not given:

• For Shorewall versions prior to 4.5.8 - all filters have priority 10.

• For Shorewall 4.5.8 and later - for each device, the compiler maintains a high-water priority with an initial value of 0. When a filter has no priority, the high-water priority is incremented by 1 and assigned to the filter. When a priority greater than the high-water priority is entered in this column, the high-water priority is set to the specified priority. An attempt to assign a priority value greater than 65535 (explicitly or implicitly) raises an error.

The default priority values used by other Shorewall-generated filters are as follows:

• Classify by packet mark - ( class priority << 8 ) | 20.

• Ingress policing - 10

• Simple TC ACK packets - 1

• Complex TC ACK packets - ( class priority << 8 ) | 10.

• Classify by TOS - ( class priority << 8 ) | 15.

• Class with 'occurs' - 65535