The Default-Router [Ip Address] Cisco command

Syntax: default-router [ip-address]

Usage: The default-router command is used to configure a default router for a Cisco router. The default router is the router that the router will use to forward packets that are not destined for any of the directly connected networks.

Effect: The default-router command adds the specified IP address to the routing table as a default route. This means that the router will send any packets that are not destined for any of the directly connected networks to the specified router.

Equipment: The default-router command can be used on all Cisco routers.

Configuration: To configure a default router, enter the following command in configuration mode:

default-router [ip-address]

For example, to configure the router to use the router with the IP address 10.0.0.1 as the default router, enter the following command:

default-router 10.0.0.1

Verification: To verify that the default router has been configured correctly, enter the following command in privileged EXEC mode:

show ip route

The output of the show ip route command will include a route to the default router. The route to the default router will have a destination of 0.0.0.0 and a next hop of the IP address of the default router.

Troubleshooting: If you are having problems configuring a default router, check the following:

Make sure that the IP address of the default router is correct.
Make sure that the default router is reachable from the router.
Make sure that the default route is not being overridden by a more specific route.

default-router [ip address] Usage Examples

The default-router [ip address] command specifies the IP address of the default next-hop router to use for forwarding packets outside of the local network. This command can be used on the following interfaces:

Ethernet
ATM
Frame Relay
PPP
Serial
ISDN

The following are examples of the default-router [ip address] command:

To specify the default router IP address on Ethernet interface Ethernet0/1:
```
interface Ethernet0/1
default-router 192.168.1.254
```
To specify the default router IP address on ATM interface ATM0/1:
```
interface ATM0/1
default-router 172.16.1.254
```
To specify the default router IP address on Frame Relay interface Frame-Relay0/1:
```
interface Frame-Relay0/1
default-router 10.0.0.254
```
To specify the default router IP address on PPP interface PPP0:
```
interface PPP0
default-router 203.0.113.1
```
To specify the default router IP address on Serial interface Serial0/0:
```
interface Serial0/0
default-router 192.0.2.254
```
To specify the default router IP address on ISDN interface ISDN0:
```
interface ISDN0
default-router 192.168.2.254
```