Provided by: iproute2_5.5.0-1ubuntu1_amd64 bug


       ip-rule - routing policy database management


       ip [ OPTIONS ] rule { COMMAND | help }

       ip rule [ list [ SELECTOR ]]

       ip rule { add | del } SELECTOR ACTION

       ip rule { flush | save | restore }

       SELECTOR := [ not ] [ from PREFIX ] [ to PREFIX ] [ tos TOS ] [ fwmark FWMARK[/MASK] ] [
               iif STRING ] [ oif STRING ] [ pref NUMBER ] [ l3mdev ] [ uidrange NUMBER-NUMBER ]
               [ ipproto PROTOCOL ] [ sport [ NUMBER | NUMBER-NUMBER ] ] [ dport [ NUMBER |
               NUMBER-NUMBER ] ] [ tun_id TUN_ID ]

       ACTION := [ table TABLE_ID ] [ protocol PROTO ] [ nat ADDRESS ] [ realms

       SUPPRESSOR := [ suppress_prefixlength NUMBER ] [ suppress_ifgroup GROUP ]

       TABLE_ID := [ local | main | default | NUMBER ]


       ip rule manipulates rules in the routing policy database control the route selection

       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 order of decreasing priority (note that lower number means higher priority, see
       the description of PREFERENCE below). 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 indication and the RPDB lookup is
       terminated. Otherwise, the RPDB program continues with the next rule.

       Semantically, the 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 containing high priority control routes
              for local and broadcast addresses.

       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

              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

              tos TOS

              dsfield TOS
                     select the TOS value to match.

              fwmark MARK
                     select the fwmark value to match.

              uidrange NUMBER-NUMBER
                     select the uid value to match.

              ipproto PROTOCOL
                     select the ip protocol value to match.

              sport NUMBER | NUMBER-NUMBER
                     select the source port value to match. supports port range.

              dport NUMBER | NUMBER-NUMBER
                     select the destination port value to match. supports port range.

              priority PREFERENCE
                     the priority of this rule.  PREFERENCE is an unsigned integer value, higher
                     number means lower priority, and rules get processed in order of increasing
                     number. 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.

              protocol PROTO
                     the routing protocol who installed the rule in question.  As an example when
                     zebra installs a rule it would get RTPROT_ZEBRA as the installing protocol.

              suppress_prefixlength NUMBER
                     reject routing decisions that have a prefix length of NUMBER or less.

              suppress_ifgroup GROUP
                     reject routing decisions that use a device belonging to the interface group

              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 packets, 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.

              protocol PROTO
                     Select the originating protocol.

       ip rule show - list rules
              This command has no arguments.  The options list or lst are synonyms with show.

       ip rule save

              protocol PROTO
                     Select the originating protocol.

       save rules table information to stdout
              This command behaves like ip rule show except that the output is raw data suitable
              for passing to ip rule restore.

       ip rule restore
              restore rules table information from stdin
              This command expects to read a data stream as returned from ip rule save.  It will
              attempt to restore the rules table information exactly as it was at the time of the
              save. Any rules already in the table are left unchanged, and duplicates are not




       Original Manpage by Michail Litvak <>