Finding Your Internal IP (OS X 10.5 and Newer): Click on the Apple icon on the upper-left corner of. Ip route del has the same arguments as ip route add, but their semantics are a bit different. Key values (to, tos, preference and table) select the route to delete. If optional attributes are present, ip verifies that they coincide with the attributes of the route to delete. If no route with the given key and attributes was found, ip route del. To create static routes, you use the 'staticroute' program (which you'll find in /usr/local/sbin). Staticroute add 10.128.4.0/24 'Main Network Interface' staticroute delete 10.192.0.0/16 'Other Interface' You can also see the list of configured static routes with. Staticroute list and a list of interface names with. Staticroute list-interfaces.
IP routing is the process of sending packets from a host on one network to another host on a different remote network. This process is usually done by routers. Routers examine the destination IP address of a packet , determine the next-hop address, and forward the packet. Routers use routing tables to determine the next hop address to which the packet should be forwarded.
Consider the following example of IP routing:
Host A wants to communicate with host B, but host B is on another network. Host A is configured to send all packets destined for remote networks to router R1. Router R1 receives the packets, examines the destination IP address and forwards the packet to the outgoing interface associated with the destination network.
Default gateway
A default gateway is a router that hosts use to communicate with other hosts on remote networks. A default gateway is used when a host doesn’t have a route entry for the specific remote network and doesn’t know how to reach that network. Hosts can be configured to send all packets destined to remote networks to the default gateway, which has a route to reach that network.
How To Find Router Mac Address
The following example explains the concept of a default gateway more thoroughly.
Host A has an IP address of the router R1 configured as the default gateway address. Host A is trying to communicate with host B, a host on another, remote network. Host A looks up in its routing table to check if there is an entry for that destination network. If the entry is not found, the host sends all data to the router R1. Router R1 receives the packets and forwards them to host B.
Routing table
Each router maintains a routing table and stores it in RAM. A routing table is used by routers to determine the path to the destination network. Each routing table consists of the following entries:
- network destination and subnet mask – specifies a range of IP addresses.
- remote router – IP address of the router used to reach that network.
- outgoing interface – outgoing interface the packet should go out to reach the destination network.
There are three different methods for populating a routing table:
- directly connected subnets
- using static routing
- using dynamic routing
Each of this method will be described in the following chapters.
Consider the following example. Host A wants to communicate with host B, but host B is on another network. Host A is configured to send all packets destined for remote networks to the router. The router receives the packets, checks the routing table to see if it has an entry for the destination address. If it does, the router forwards the packet out the appropriate interface port. If the router doesn’t find the entry, it discards the packet.
We can use the show ip route command from the enabled mode to display the router’s routing table.
As you can see from the output above, this router has two directly connected routes to the subnets 10.0.0.0/8 and 192.168.0.0/24. The character C in the routing table indicates that a route is a directly connected route. So when host A sends the packet to host B, the router will look up into its routing table and find the route to the 10.0.0.0/8 network on which host B resides. The router will then use that route to route packets received from host A to host B.
This tutorial explains IP route command and its parameter, argument and options in detail with examples. Learn how to configure default route and static route with IP route command in Cisco router step by step with practical example in packet tracer.
IP route command is used to configure the static route. Static routes are the most secure way of routing. They will also increase overall network performance. These features are extremely helpful in small network.
IP route command and parameters explained
We have two commands to configure the static route.
and
Let’s explore above commands in detail
ip route
This is the base command which adds new route in routing table.
destination_network_#[subnet_mask]
This is the first parameter. It specifies the destination network address. We need to provide subnet mask if we are using sub-network. Sub-networks are the smaller networks created from one large network in subnetting. If we are not using sub-network then we can omit the subnet mask value. It will parse automatically.
Ip Route Mac Os X
IP_address_of_next_hop_neighbor / interface_to_exit
This parameter provides a way to reach the destination network. Both commands use separate way to assign this value. First command provides the IP address of next hop neighbor. It tells router that if it receives a packet for destination [that we set in previous parameter], forward that packet to this next hop neighbor IP address.
Second command also do the same job but in different way. It specifies exit interface instead of next hop IP address. It tells router that if it receives a packet for the destination specified by previous parameter then exits that packet from this interface. Device attached on other end of this interface will take care of the packet.
administrative_distance
Administrative distance is the trustworthiness of route. Route with the lowest AD value will be chosen while forwarding the packet. By default static route has two AD values depending on the previous parameter. If you have used next hop neighbor IP address, then the default AD value will be 1. If you have used exit interface, then the default AD value will be 0. This parameter allows us to create multiple static routes for the same destination. For example we can create primary and backup path for the destination network. To create backup path, we need to set AD value to higher than default, such as 2 or 3. With this configuration router will use primary path. Due to some reason if primary route fails, the router will start using backup route automatically.
permanent
When a route goes down router will remove that from routing table. Permanent parameter will keep this route in routing table even if it goes down. Its optional parameter we can omit it. If we omit it, router will remove this route from routing table if it goes down. You might use this parameter for security reason if you never want packets to take another path.
Configure Default Route
By default when a packet arrives in interface, router checks destination filed in packet and compare it with routing table. If it finds a match for destination network then it will forward that packet from related interface. If it does not find a match in routing table then it will discard that packet. This is the default behavior of router. Default route allows us to override this behavior. Default route is a way to deal with all unmatched packets. If no match for destination network found in routing table then it would be forwarded to the default route.
Following commands are used to set the default route
Or
Above command sets destination network to 0.0.0.0/0 that represents all networks.
IP route command example
For demonstration purpose we will use Packet Tracer network simulator software. Beside Packet Tracer you can use any other network simulator software such RouterSim, GNS, Boson or even better if you could afford, use real Cisco devices for follow this practice.
Create a practice topology as shown in fowling figure. Alternatively you can download this topology.
| Device | Connected from | Connected to | IP Address |
| PC0 | FastEthernet0 | Router0's FastEthernet0/0 | 10.0.0.2/8 |
| Router0 | FastEthernet0/0 | PC0's FastEthernet0 | 10.0.0.1/8 |
| Router0 | Serial 0/0/0 | Router1's serial0/0/0 | 192.168.0.253/30 |
| Router1 | Serial 0/0/0/ | Router0's serial0/0/0 | 192.168.0.254/30 |
| Router1 | FastEthernet0/0 | PC1's FastEthernet0 | 20.0.0.1/8 |
| PC1 | FastEthernet0 | Router1's FastEthernet0/0 | 20.0.0.2/8 |
Assign IP address to devices
Assign IP address 10.0.0.2/8 to PC0.
Repeat same process for PC1 and assign IP address 20.0.0.2/8.
Assign IP address to interfaces of router
Double click Router0 and click CLI and press Enter key to access command prompt of router.
Two interfaces FastEthernet0/0 and Serial0/0/0 of Router0 are used in this topology. By default interfaces on router are remain administratively down during the start up. We need to configure IP address and other parameters on interfaces before we could actually use them for routing. Interface mode is used to assign IP address and other parameters. Interface mode can be accessed from global configuration mode. Following commands are used to access global configuration mode.
From global configuration mode we can enter in interface mode. From there we can configure the interface. Following commands will assign IP address on FastEthernet0/0.
interface fastEthernet 0/0 command is used to enter in interface mode.
ip address 10.0.0.2 255.0.0.0 command will assign IP address to interface.
no shutdown command will bring the interface up.
exit command is used to return in global configuration mode.
Serial interface needs two additional parameters clock rate and bandwidth. Every serial cable has two ends DTE and DCE. These parameters are always configured at DCE end. We can use show controllers interface command from privilege mode to check the cable's end.
Fourth line of output confirms that DCE end of serial cable is attached. If you see DTE here instead of DCE skip these parameters.
Now we have necessary information let's assign IP address to serial interface.
Router#configure terminal Command is used to enter in global configuration mode.
Router(config)#interface serial 0/0/0 Command is used to enter in interface mode.
Router(config-if)#ip address 192.168.0.253 255.255.255.252 Command assigns IP address to interface. For serial link we usually use IP address from /30 subnet.
Router(config-if)#clock rate 64000 And Router(config-if)#bandwidth 64 In real life environment these parameters control the data flow between serial links and need to be set at service providers end. In lab environment we need not to worry about these values. We can use these values.
Router(config-if)#no shutdown Command brings interface up.
Router(config-if)#exit Command is used to return in global configuration mode.
We will use same commands to assign IP addresses on interfaces of Router1. Since we have provided clock rate and bandwidth on serial interface of Router0 we need not to assign them on serial interface of Router1. Following command will assign IP addresses on interface of Router1.
Configure Static Route
Run following command from global configuration mode in routers.
Router0
Router1
That's all we need to switch packet from one network to another. To verify the result we can use ping command. Access the command prompt of PC1 and use ping command to test the connectivity from PC0.
A successful reply indicates that static routing is configured properly. In next article we will extend this example with more complex topology.