SHOREWALL\-TCFILTERS

Section: Configuration Files (5)
Updated: 04/11/2019
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NAME

tcfilters - Shorewall u32/basic classifier rules file

SYNOPSIS

/etc/shorewall[6]/tcfilters

DESCRIPTION

Entries in this file cause packets to be classified for traffic shaping.

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

EXAMPLE

IPv4 Example 1:

Place all 'ping' traffic on interface 1 in class 10. Note that ALL cannot be used because IPv4 ICMP and IPv6 ICMP are two different protocols.

       #CLASS    SOURCE    DEST         PROTO   DPORT

       IPV4

       1:10      0.0.0.0/0 0.0.0.0/0    icmp    echo-request
       1:10      0.0.0.0/0 0.0.0.0/0    icmp    echo-reply

       IPV6

       1:10      ::/0      ::/0         icmp6   echo-request
       1:10      ::/0      ::/0         icmp6   echo-reply

IPv4 Example 2:

Add two filters with priority 10 (Shorewall 4.5.8 or later).

       #CLASS    SOURCE    DEST         PROTO   DPORT           PRIORITY

       IPV4

       1:10      0.0.0.0/0 0.0.0.0/0    icmp    echo-request    10
       1:10      0.0.0.0/0 0.0.0.0/0    icmp    echo-reply      10

IPv6 Example 1:

Add two filters with priority 10 (Shorewall 4.5.8 or later).

       #CLASS    SOURCE    DEST         PROTO   DPORT           PRIORITY

       IPV6

       1:10      ::/0      ::/0         icmp    echo-request    10
       1:10      ::/0      ::/0         icmp    echo-reply      10