Lines Matching defs:Route
115 \item \verb|route| --- routing table entry
1072 \section{{\tt ip route} --- routing table management}
1073 \label{IP-ROUTE}
1075 \paragraph{Abbreviations:} \verb|route|, \verb|ro|, \verb|r|.
1077 \paragraph{Object:} \verb|route| entries in the kernel routing tables keep
1080 Each route entry has a {\em key\/} consisting of a {\em prefix\/}
1082 optionally, the TOS value. An IP packet matches the route if the highest
1083 bits of its destination address are equal to the route prefix at least
1084 up to the prefix length and if the TOS of the route is zero or equal to
1093 \item If the TOS of some route with the longest prefix is equal to the TOS
1099 Otherwise, the route lookup fails.
1110 word ``first'' depends on the order of route additions and it is practically
1119 One useful exception to this rule is the default route on non-forwarding
1137 the statements above as: a route is identified by the triplet
1139 the route in the routing table.
1141 \paragraph{Route attributes:} Each route key refers to a routing
1148 \paragraph{Route types:} \label{IP-ROUTE-TYPES}
1150 of required and optional attributes depend on the route {\em type\/}.
1151 The most important route type
1157 \item \verb|unicast| --- the route entry describes real paths to the
1158 destinations covered by the route prefix.
1171 \item \verb|throw| --- a special control route used together with policy
1172 rules (see sec.\ref{IP-RULE}, p.\pageref{IP-RULE}). If such a route is selected, lookup
1173 in this table is terminated pretending that no route was found.
1174 Without policy routing it is equivalent to the absence of the route in the routing
1177 \item \verb|nat| --- a special NAT route. Destinations covered by the prefix
1181 in Appendix~\ref{ROUTE-NAT}, p.\pageref{ROUTE-NAT}.
1190 \paragraph{Route tables:} Linux-2.2 can pack routes into several routing
1206 \{prefix, tos, preference\} to uniquely identify the route.
1209 \subsection{{\tt ip route add} --- add a new route\\
1210 {\tt ip route change} --- change a route\\
1211 {\tt ip route replace} --- change a route or add a new one}
1212 \label{IP-ROUTE-ADD}
1222 --- the destination prefix of the route. If \verb|TYPE| is omitted,
1226 \verb|ip| assumes a full-length host route. There is also a special
1234 of the route and of the packet. If they are not equal, then the packet
1235 may still match a route with a zero TOS. \verb|TOS| is either an 8 bit hexadecimal
1241 --- the preference value of the route. \verb|NUMBER| is an arbitrary 32bit number.
1245 --- the table to add this route to.
1259 on the route type. For normal \verb|unicast| routes it is either the true nexthop
1260 router or, if it is a direct route installed in BSD compatibility mode,
1267 covered by the route prefix.
1271 --- the realm to which this route is assigned.
1348 route. \verb|NEXTHOP| is a complex value
1354 route reflecting its relative bandwidth or quality.
1359 --- the scope of the destinations covered by the route prefix.
1369 --- the routing protocol identifier of this route.
1373 it assumes the route was added by someone who doesn't
1377 \item \verb|redirect| --- the route was installed due to an ICMP redirect.
1378 \item \verb|kernel| --- the route was installed by the kernel during
1380 \item \verb|boot| --- the route was installed during the bootup sequence.
1382 \item \verb|static| --- the route was installed by the administrator
1385 \item \verb|ra| --- the route was installed by Router Discovery protocol.
1405 thing as classic \verb|route add|, i.e.\ adds a route, even if another
1406 route to the same destination exists. Its opposite case is \verb|append|,
1407 which adds the route to the end of the list. Avoid these
1418 \item add a plain route to network 10.0.0/24 via gateway 193.233.7.65
1420 ip route add 10.0.0/24 via 193.233.7.65
1422 \item change it to a direct route via the \verb|dummy| device
1426 \item add a default multipath route splitting the load between \verb|ppp0|
1429 ip route add default scope global nexthop dev ppp0 \
1433 that this route is gatewayed rather than direct. Actually, if you
1439 ip route add nat 192.203.80.144 via 193.233.7.83
1445 \subsection{{\tt ip route delete} --- delete a route}
1449 \paragraph{Arguments:} \verb|ip route del| has the same arguments as
1450 \verb|ip route add|, but their semantics are a bit different.
1453 select the route to delete. If optional attributes are present, \verb|ip|
1454 verifies that they coincide with the attributes of the route to delete.
1455 If no route with the given key and attributes was found, \verb|ip route del|
1458 Linux-2.0 had the option to delete a route selected only by prefix address,
1460 because it was ambiguous. However, look at {\tt ip route flush}
1461 (sec.\ref{IP-ROUTE-FLUSH}, p.\pageref{IP-ROUTE-FLUSH}) which
1467 \item delete the multipath route created by the command in previous subsection
1469 ip route del default scope global nexthop dev ppp0 \
1476 \subsection{{\tt ip route show} --- list routes}
1481 or the route(s) selected by some criteria.
1522 other routes because some route attribute (f.e.\ MTU) was updated.
1580 of per route records separated by line feeds.
1582 of more than one line: particularly, this is the case when the route
1587 The output has the same syntax as arguments given to {\tt ip route add},
1597 are evaluated during route calculation and updated during route
1609 \label{NB-strange-route}
1610 The route looks a bit strange, doesn't it? Did you notice that
1612 see in the section on \verb|ip route get| (p.\pageref{NB-nature-of-strangeness})
1625 in an error. See attribute \verb|error| below (p.\pageref{IP-ROUTE-GET-error}).
1634 \item \verb|redirected| --- the route was created by an ICMP Redirect.
1636 \item \verb|redirect| --- packets going via this route will
1639 \item \verb|fastroute| --- the route is eligible to be used for fastroute.
1652 of this route will trigger RTNETLINK notification.
1658 returned to local senders when they try to use this route.
1661 devoted to route types (p.\pageref{IP-ROUTE-TYPES}).
1662 \label{IP-ROUTE-GET-error}
1671 information about this route is shown:
1674 \item \verb|age| --- shows when this route was last used.
1675 \item \verb|used| --- the number of lookups of this route since its creation.
1679 \subsection{{\tt ip route flush} --- flush routing tables}
1680 \label{IP-ROUTE-FLUSH}
1688 as the arguments of \verb|ip route show|, but routing tables are not
1697 twice, \verb|ip route flush| also dumps all the deleted routes
1707 This option was described in the \verb|route(8)| man page borrowed
1755 \subsection{{\tt ip route get} --- get a single route}
1756 \label{IP-ROUTE-GET}
1760 \paragraph{Description:} this command gets a single route to a destination
1788 the route with the source set to the preferred address received from the first lookup.
1789 If policy routing is used, it may be a different route.
1793 Note that this operation is not equivalent to \verb|ip route show|.
1797 If the \verb|iif| argument is not given, the kernel creates a route
1800 with a subsequent {\tt ip route ls cache}, however, no packets are
1806 format as \verb|ip route ls|.
1810 \item Find a route to output packets to 193.233.7.82:
1812 kuznet@amber:~ $ ip route get 193.233.7.82
1818 \item Find a route to forward packets arriving on \verb|eth0|
1829 This is the command that created the funny route from 193.233.7.82
1830 looped back to 193.233.7.82 (cf.\ NB on~p.\pageref{NB-strange-route}).
1834 \item Find a multicast route for packets arriving on \verb|eth0|
1845 This route differs from the ones seen before. It contains a ``normal'' part
1849 of this group, so that route has no \verb|local| flag and only
1857 gatewayed route for a destination which is really directly connected:
1859 netadm@alisa:~ # ip route add 193.233.7.98 via 193.233.7.254
1860 netadm@alisa:~ # ip route get 193.233.7.98
1884 We may retry \verb|ip route get| to see what we have in the routing
1887 netadm@alisa:~ # ip route get 193.233.7.98
1901 the route selection algorithm.
1908 In some circumstances we want to route packets differently depending not only
1947 In this case, it will either give a route or failure indication
1956 a route from these tables according to the classic longest match algorithm.
1958 when a second level routing table contains a single default route.
1960 managed with the \verb|ip route| command, described in the previous section.
2001 are only used if the route did not select any attributes.
2007 \item \verb|unicast| --- the rule prescribes to return the route found
2016 in Appendix~\ref{ROUTE-NAT}, p.\pageref{ROUTE-NAT}.
2085 succeeded. Realm \verb|TO| is only used if the route did not select
2095 More about NAT is in Appendix~\ref{ROUTE-NAT},
2096 p.\pageref{ROUTE-NAT}.
2103 with \verb|ip route flush cache|.
2107 \item Route packets with source addresses from 192.203.80/24
2114 and route it according to table \#1 (actually, it is \verb|inr.ruhep|):
2306 --- the prefix selecting the IP source addresses of the multicast route.
2332 number of packets and bytes forwarded along this route and
2405 not be able to escape to another device when the route to endpoint changes.
2495 transmitted because there is no IP route to the remote endpoint.
2513 It may contain \verb|link|, \verb|address| and \verb|route|.
2537 \section{Route realms and policy propagation, {\tt rtacct}}
2542 per route, we will have to keep lots of information. Even worse, if we
2552 check all the route attributes, including ASPATH information
2563 attributes. F.e.\ a BGP router knows route ASPATH, its community;
2564 an OSPF router knows the route tag or its area. The administrator, when adding
2569 So each route may be assigned to a realm. It is assumed that
2571 can also be handled manually with \verb|ip route| (see sec.\ref{IP-ROUTE},
2572 p.\pageref{IP-ROUTE}).
2587 \item If the route has a realm, the destination realm of the packet is set to it.
2589 If the destination realm was not inherited from the route and the rule has a destination realm,
2592 the reversed route to the source of the packet.
2593 \item If the source realm is still unknown, get it from the reversed route.
2603 The main application of realms is the TC \verb|route| classifier~\cite{TC-CREF},
2623 \verb|rtacct| shows incoming packets only. Using the \verb|route|
2707 to the \verb|ip route| command, sec.\ref{IP-ROUTE}, p.\pageref{IP-ROUTE}.
2720 which fall to the same subnet as the nexthop of the route
2723 in routing tables instead (the \verb|scope| parameter to the \verb|ip route| command,
2724 sec.\ref{IP-ROUTE}, p.\pageref{IP-ROUTE}).
2748 the route to the requested destination does {\em not\/} go back via the same
2783 \verb|ip neigh|, the router {\em will not\/} answer a query if the route
2793 \section{Route NAT status}
2794 \label{ROUTE-NAT}
2797 of the IP address space into other ones. Linux-2.2 route NAT is supposed
2806 Route NAT is {\em stateless\/}. It does not hold any state
2826 active FTP clients happy, your choice is not route NAT but masquerading,
2840 A great advantage of route NAT is that it may be used not
2844 These addresses are selected by the \verb|ip route| command
2845 (sec.\ref{IP-ROUTE-ADD}, p.\pageref{IP-ROUTE-ADD}). F.e.\
2847 ip route add nat 192.203.80.144 via 193.233.7.83
2859 ip route add nat 192.203.80.192/26 via 193.233.7.64
2875 is some NAT address, declared by {\tt ip route add nat}.
2900 contain a route to the destination (which means that the routing
3055 \# 3. Add default multicast route.
3058 ip route add unreachable 224.0.0.0/24
3059 ip route add unreachable 255.255.255.255
3061 ip route add 224.0.0.0/4 dev $dev scope global
3066 \# {\bf Step 6} --- Add fallback default route with huge metric.\\
3069 \# It is not so cheap though and we still hope that this route\\
3295 \# 3. Add default multicast route.
3298 ip route add unreachable 224.0.0.0/24 >& /dev/null
3299 ip route add unreachable 255.255.255.255 >& /dev/null
3301 ip route add 224.0.0.0/4 dev $dev scope global >& /dev/null
3305 \# {\bf Step 5} --- Add fallback default route with huge metric.\\
