Configure IP Static Routes
IPv4 Next-Hop Static Route
The commands to configure standard static routes varies slightly between IPv4 and IPv6. This topic shows you how to configure standard next-hop, directly connected, and full specified static routes for both IPv4 and Ipv6.
In a next-hop static route, only the next-hop IP address is specified. The exit interface is derived from the next hop. For example, three next-hop IPv4 static routes are configured on R1 using the IP address of the next hop, R2.
The commands to configure R1 with the IPv4 static routes to the three remote networks are as follows:
R1(config)# ip route 172.16.1.0 255.255.255.0 172.16.2.2
R1(config)# ip route 192.168.1.0 255.255.255.0 172.16.2.2
R1(config)# ip route 192.168.2.0 255.255.255.0 172.16.2.2The routing table for R1 now has routes to the three remote IPv4 networks.
R1# show ip route | begin Gateway
Gateway of last resort is not set
172.16.0.0/16 is variably subnetted, 5 subnets, 2 masks
S 172.16.1.0/24 [1/0] via 172.16.2.2
C 172.16.2.0/24 is directly connected, Serial0/1/0
L 172.16.2.1/32 is directly connected, Serial0/1/0
C 172.16.3.0/24 is directly connected, GigabitEthernet0/0/0
L 172.16.3.1/32 is directly connected, GigabitEthernet0/0/0
S 192.168.1.0/24 [1/0] via 172.16.2.2
S 192.168.2.0/24 [1/0] via 172.16.2.2R1#
IPv6 Next-Hop Static Route
The commands to configure R1 with the IPv6 static routes to the three remote networks are as follows:
R1(config)# ipv6 unicast-routing
R1(config)# ipv6 route 2001:db8:acad:1::/64 2001:db8:acad:2::2
R1(config)# ipv6 route 2001:db8:cafe:1::/64 2001:db8:acad:2::2
R1(config)# ipv6 route 2001:db8:cafe:2::/64 2001:db8:acad:2::2The routing table for R1 now has routes to the three remote IPv6 networks.
R1# show ipv6 route
IPv6 Routing Table - default - 8 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
B - BGP, R - RIP, H - NHRP, I1 - ISIS L1
I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary, D - EIGRP
EX - EIGRP external, ND - ND Default, NDp - ND Prefix, DCE - Destination
NDr - Redirect, RL - RPL, O - OSPF Intra, OI - OSPF Inter
OE1 - OSPF ext 1, OE2 - OSPF ext 2, ON1 - OSPF NSSA ext 1
ON2 - OSPF NSSA ext 2, la - LISP alt, lr - LISP site-registrations
ld - LISP dyn-eid, lA - LISP away, le - LISP extranet-policy
a - Application
S 2001:DB8:ACAD:1::/64 [1/0]
via 2001:DB8:ACAD:2::2
C 2001:DB8:ACAD:2::/64 [0/0]
via Serial0/1/0, directly connected
L 2001:DB8:ACAD:2::1/128 [0/0]
via Serial0/1/0, receive
C 2001:DB8:ACAD:3::/64 [0/0]
via GigabitEthernet0/0/0, directly connected
L 2001:DB8:ACAD:3::1/128 [0/0]
via GigabitEthernet0/0/0, receive
S 2001:DB8:CAFE:1::/64 [1/0]
via 2001:DB8:ACAD:2::2
S 2001:DB8:CAFE:2::/64 [1/0]
via 2001:DB8:ACAD:2::2
L FF00::/8 [0/0]
via Null0, receiveIPv4 Directly Connected Static Route
When configuring a static route, another option is to use the exit interface to specify the next-hop address. The figure shows the topology again.
Three directly connected IPv4 static routes are configured on R1 using the exit interface.
R1(config)# ip route 172.16.1.0 255.255.255.0 s0/1/0
R1(config)# ip route 192.168.1.0 255.255.255.0 s0/1/0
R1(config)# ip route 192.168.2.0 255.255.255.0 s0/1/0The IPv4 routing table for R1 shows that when a packet is destined for the 192.168.2.0/24 network, R1 looks for a match in the routing table, and finds that it can forward the packet out of its Serial 0/1/0 interface.
Note: Using a next-hop address is generally recommended. Directly connected static routes should only be used with point-to-point serial interfaces, as in this example.
R1# show ip route | begin Gateway
Gateway of last resort is not set
172.16.0.0/16 is variably subnetted, 5 subnets, 2 masks
S 172.16.1.0/24 is directly connected, Serial0/1/0
C 172.16.2.0/24 is directly connected, Serial0/1/0
L 172.16.2.1/32 is directly connected, Serial0/1/0
C 172.16.3.0/24 is directly connected, GigabitEthernet0/0/0
L 172.16.3.1/32 is directly connected, GigabitEthernet0/0/0
S 192.168.1.0/24 is directly connected, Serial0/1/0
S 192.168.2.0/24 is directly connected, Serial0/1/0IPv6 Directly Connected Static Route
In the example, three directly connected IPv6 static routes are configured on R1 using the exit interface.
R1(config)# ipv6 route 2001:db8:acad:1::/64 s0/1/0
R1(config)# ipv6 route 2001:db8:cafe:1::/64 s0/1/0
R1(config)# ipv6 route 2001:db8:cafe:2::/64 s0/1/0The IPv6 routing table for R1 in the example output shows that when a packet is destined for the 2001:db8:cafe:2::/64 network, R1 looks for a match in the routing table and finds that it can forward the packet out of its Serial 0/1/0 interface.
Note: Using a next-hop address is generally recommended. Directly connected static routes should only be used with point-to-point serial interfaces, as in this example.
R1# show ipv6 route
IPv6 Routing Table - default - 8 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
B - BGP, R - RIP, H - NHRP, I1 - ISIS L1
I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary, D - EIGRP
EX - EIGRP external, ND - ND Default, NDp - ND Prefix, DCE - Destination
NDr - Redirect, RL - RPL, O - OSPF Intra, OI - OSPF Inter
OE1 - OSPF ext 1, OE2 - OSPF ext 2, ON1 - OSPF NSSA ext 1
ON2 - OSPF NSSA ext 2, la - LISP alt, lr - LISP site-registrations
ld - LISP dyn-eid, lA - LISP away, le - LISP extranet-policy
a - Application
S 2001:DB8:ACAD:1::/64 [1/0]
via Serial0/1/0, directly connected
C 2001:DB8:ACAD:2::/64 [0/0]
via Serial0/1/0, directly connected
L 2001:DB8:ACAD:2::1/128 [0/0]
via Serial0/1/0, receive
C 2001:DB8:ACAD:3::/64 [0/0]
via GigabitEthernet0/0/0, directly connected
L 2001:DB8:ACAD:3::1/128 [0/0]
via GigabitEthernet0/0/0, receive
S 2001:DB8:CAFE:1::/64 [1/0]
via Serial0/1/0, directly connected
S 2001:DB8:CAFE:2::/64 [1/0]
via Serial0/1/0, directly connected
L FF00::/8 [0/0]
via Null0, receive
R1#IPv4 Fully Specified Static Route
In a fully specified static route, both the exit interface and the next-hop IP address are specified. This form of static route is used when the exit interface is a multi-access interface and it is necessary to explicitly identify the next hop. The next hop must be directly connected to the specified exit interface. Using an exit interface is optional, however it is necessary to use a next-hop address.
Suppose that the network link between R1 and R2 is an Ethernet link and that the GigabitEthernet 0/0/1 interface of R1 is connected to that network, as shown in the figure.
The difference between an Ethernet multi-access network and a point-to-point serial network is that a point-to-point serial network has only one other device on that network, the router at the other end of the link. With Ethernet networks, there may be many different devices sharing the same multi-access network, including hosts and even multiple routers.
It is recommended that when the exit interface is an Ethernet network, that the static route includes a next-hop address. You can also use a fully specified static route that includes both the exit interface and the next-hop address.
R1(config)# ip route 172.16.1.0 255.255.255.0 GigabitEthernet 0/0/1 172.16.2.2
R1(config)# ip route 192.168.1.0 255.255.255.0 GigabitEthernet 0/0/1 172.16.2.2
R1(config)# ip route 192.168.2.0 255.255.255.0 GigabitEthernet 0/0/1 172.16.2.2When forwarding packets to R2, the exit interface is GigabitEthernet 0/0/1 and the next-hop IPv4 address is 172.16.2.2 as shown in the show ip route output from R1.
R1# show ip route | begin Gateway
Gateway of last resort is not set
172.16.0.0/16 is variably subnetted, 5 subnets, 2 masks
S 172.16.1.0/24 [1/0] via 172.16.2.2, GigabitEthernet0/0/1
C 172.16.2.0/24 is directly connected, GigabitEthernet0/0/1
L 172.16.2.1/32 is directly connected, GigabitEthernet0/0/1
C 172.16.3.0/24 is directly connected, GigabitEthernet0/0/0
L 172.16.3.1/32 is directly connected, GigabitEthernet0/0/0
S 192.168.1.0/24 [1/0] via 172.16.2.2, GigabitEthernet0/0/1
S 192.168.2.0/24 [1/0] via 172.16.2.2, GigabitEthernet0/0/1IPv6 Fully Specified Static Route
In a fully specified IPv6 static route, both the exit interface and the next-hop IPv6 address are specified. There is a situation in IPv6 when a fully specified static route must be used. If the IPv6 static route uses an IPv6 link-local address as the next-hop address, use a fully specified static route. The figure shows an example of a fully specified IPv6 static route using an IPv6 link-local address as the next-hop address.
R1(config)# ipv6 route 2001:db8:acad:1::/64 fe80::2
%Interface has to be specified for a link-local nexthop
R1(config)# ipv6 route 2001:db8:acad:1::/64 s0/1/0 fe80::2In the example, a fully specified static route is configured using the link-local address of R2 as the next-hop address. Notice that IOS requires that an exit interface be specified.
The reason a fully specified static route must be used is because IPv6 link-local addresses are not contained in the IPv6 routing table. Link-local addresses are only unique on a given link or network. The next-hop link-local address may be a valid address on multiple networks connected to the router. Therefore, it is necessary that the exit interface be included.
The following example shows the IPv6 routing table entry for this route. Notice that both the next-hop link-local address and the exit interface are included.
R1# show ipv6 route static | begin 2001:db8:acad:1::/64
S 2001:DB8:ACAD:1::/64 [1/0]
via FE80::2, Seria0/1/0Verify a Static Route
Along with show ip route, show ipv6 route, ping and traceroute, other useful commands to verify static routes include the following:
- show ip route static
- show ip route network
- show running-config | section ip route
Replace ip with ipv6 for the IPv6 versions of the command.
Reference the figure when reviewing the command examples.
Click each button for example output for IPv4 and IPv6 static routes.
Display only IPv4 Static Routes