IP-MROUTE(8) Linux IP-MROUTE(8)NAME
ip-mroute - multicast routing cache management
SYNOPSIS
ip mroute show [ [ to ] PREFIX ] [ from PREFIX ] [ iif DEVICE ] [ table TABLE_ID ]
DESCRIPTION
mroute objects are multicast routing cache entries created by a user-level mrouting daemon (f.e. pimd or mrouted ).
Due to the limitations of the current interface to the multicast routing engine, it is impossible to change mroute objects administra-
tively, so we can only display them. This limitation will be removed in the future.
ip mroute show - list mroute cache entries
to PREFIX (default)
the prefix selecting the destination multicast addresses to list.
iif NAME
the interface on which multicast packets are received.
from PREFIX
the prefix selecting the IP source addresses of the multicast route.
table TABLE_ID
the table id selecting the multicast table. It can be local, main, default, all or a number.
SEE ALSO ip(8)AUTHOR
Original Manpage by Michail Litvak <mci@owl.openwall.com>
iproute2 13 Dec 2012 IP-MROUTE(8)
Check Out this Related Man Page
IP-RULE(8) Linux IP-RULE(8)NAME
ip-rule - routing policy database management
SYNOPSIS
ip [ OPTIONS ] rule { COMMAND | help }
ip rule [ list | add | del | flush ] SELECTOR ACTION
SELECTOR := [ from PREFIX ] [ to PREFIX ] [ tos TOS ] [ fwmark FWMARK[/MASK] ] [ iif STRING ] [ oif STRING ] [ pref NUMBER ]
ACTION := [ table TABLE_ID ] [ nat ADDRESS ] [ prohibit | reject | unreachable ] [ realms [SRCREALM/]DSTREALM ]
TABLE_ID := [ local | main | default | NUMBER ]
DESCRIPTION
ip rule manipulates rules in the routing policy database control the route selection algorithm.
Classic routing algorithms used in the Internet make routing decisions based only on the destination address of packets (and in theory, but
not in practice, on the TOS field).
In some circumstances we want to route packets differently depending not only on destination addresses, but also on other packet fields:
source address, IP protocol, transport protocol ports or even packet payload. This task is called 'policy routing'.
To solve this task, the conventional destination based routing table, ordered according to the longest match rule, is replaced with a
'routing policy database' (or RPDB), which selects routes by executing some set of rules.
Each policy routing rule consists of a selector and an action predicate. The RPDB is scanned in the order of increasing priority. The
selector of each rule is applied to {source address, destination address, incoming interface, tos, fwmark} and, if the selector matches the
packet, the action is performed. The action predicate may return with success. In this case, it will either give a route or failure indi-
cation and the RPDB lookup is terminated. Otherwise, the RPDB program continues on the next rule.
Semantically, natural action is to select the nexthop and the output device.
At startup time the kernel configures the default RPDB consisting of three rules:
1. Priority: 0, Selector: match anything, Action: lookup routing table local (ID 255). The local table is a special routing table con-
taining high priority control routes for local and broadcast addresses.
Rule 0 is special. It cannot be deleted or overridden.
2. Priority: 32766, Selector: match anything, Action: lookup routing table main (ID 254). The main table is the normal routing table
containing all non-policy routes. This rule may be deleted and/or overridden with other ones by the administrator.
3. Priority: 32767, Selector: match anything, Action: lookup routing table default (ID 253). The default table is empty. It is
reserved for some post-processing if no previous default rules selected the packet. This rule may also be deleted.
Each RPDB entry has additional attributes. F.e. each rule has a pointer to some routing table. NAT and masquerading rules have an
attribute to select new IP address to translate/masquerade. Besides that, rules have some optional attributes, which routes have, namely
realms. These values do not override those contained in the routing tables. They are only used if the route did not select any
attributes.
The RPDB may contain rules of the following types:
unicast - the rule prescribes to return the route found in the routing table referenced by the rule.
blackhole - the rule prescribes to silently drop the packet.
unreachable - the rule prescribes to generate a 'Network is unreachable' error.
prohibit - the rule prescribes to generate 'Communication is administratively prohibited' error.
nat - the rule prescribes to translate the source address of the IP packet into some other value.
ip rule add - insert a new rule
ip rule delete - delete a rule
type TYPE (default)
the type of this rule. The list of valid types was given in the previous subsection.
from PREFIX
select the source prefix to match.
to PREFIX
select the destination prefix to match.
iif NAME
select the incoming device to match. If the interface is loopback, the rule only matches packets originating from this host. This
means that you may create separate routing tables for forwarded and local packets and, hence, completely segregate them.
oif NAME
select the outgoing device to match. The outgoing interface is only available for packets originating from local sockets that are
bound to a device.
tos TOS
dsfield TOS
select the TOS value to match.
fwmark MARK
select the fwmark value to match.
priority PREFERENCE
the priority of this rule. Each rule should have an explicitly set unique priority value. The options preference and order are
synonyms with priority.
table TABLEID
the routing table identifier to lookup if the rule selector matches. It is also possible to use lookup instead of table.
realms FROM/TO
Realms to select if the rule matched and the routing table lookup succeeded. Realm TO is only used if the route did not select any
realm.
nat ADDRESS
The base of the IP address block to translate (for source addresses). The ADDRESS may be either the start of the block of NAT
addresses (selected by NAT routes) or a local host address (or even zero). In the last case the router does not translate the pack-
ets, but masquerades them to this address. Using map-to instead of nat means the same thing.
Warning: Changes to the RPDB made with these commands do not become active immediately. It is assumed that after a script finishes
a batch of updates, it flushes the routing cache with ip route flush cache.
ip rule flush - also dumps all the deleted rules.
This command has no arguments.
ip rule show - list rules
This command has no arguments. The options list or lst are synonyms with show.
SEE ALSO ip(8)AUTHOR
Original Manpage by Michail Litvak <mci@owl.openwall.com>
iproute2 20 Dec 2011 IP-RULE(8)