Default routing configuration instance learning record

Default routing configuration instance

The default route is a special static route , Its network address and subnet mask are all 0

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1、 The goal of the experiment

Learn how to configure the default route , Understand the difference between default routing and static routing

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2、 Network topology

notes ：PC Of IP Address 、 Subnet mask and gateway , Click on PC Enter self configuration

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3、 Configuration steps

（1） Configure ports by topology IP Address

R1 To configure ：

<R1>system-view  // Enter the system view 
[R1]interface Ethernet0/0/0
[R1-Ethernet0/0/0]ip address 20.1.1.1 24  // configure port  IP  Address （IP  Address : 20.1.1.1  Subnet mask : 24）
[R1-Ethernet0/0/0]quit
[R1]interface GigabitEthernet0/0/0
[R1-GigabitEthernet0/0/0]ip address 10.1.1.1 24  // configure port  IP  Address （IP  Address : 10.1.1.1  Subnet mask : 24）
[R1-GigabitEthernet0/0/0]quit

R2 To configure ：

<R2>system-view  // Enter the system view 
[R2]interface Ethernet0/0/0
[R2-Ethernet0/0/0]ip address 30.1.1.1 24  // configure port  IP  Address （IP  Address : 30.1.1.1  Subnet mask : 24）
[R2-Ethernet0/0/0]quit
[R2]interface Ethernet0/0/1
[R2-Ethernet0/0/1]ip address 40.1.1.1 24  // configure port  IP  Address （IP  Address : 40.1.1.1  Subnet mask : 24）
[R2-Ethernet0/0/1]quit
[R2]interface GigabitEthernet0/0/0
[R2-GigabitEthernet0/0/0]ip address 10.1.1.2 24  // configure port  IP  Address （IP  Address : 10.1.1.2  Subnet mask : 24）
[R2-GigabitEthernet0/0/0]quit

（2） Configure the default route

R1 To configure ：

[R1]ip route-static 0.0.0.0 0.0.0.0 10.1.1.2  //ip route-static [0.0.0.0] [0.0.0.0] [ Next jump  IP  Address ]

R2 To configure ：

[R2]ip route-static 0.0.0.0 0.0.0.0 10.1.1.1  //ip route-static [0.0.0.0] [0.0.0.0] [ Next jump  IP  Address ]

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4、 test

（1） View the established route entries , See if there is a default route

see R1 Routing table ：

[R1]display ip routing-table  // View routing table 
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Tables: Public
         Destinations : 7        Routes : 7        

Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface

        0.0.0.0/0   Static  60   0          RD   10.1.1.2        GigabitEthernet  // This is the default route 
0/0/0
       10.1.1.0/24  Direct  0    0           D   10.1.1.1        GigabitEthernet
0/0/0
       10.1.1.1/32  Direct  0    0           D   127.0.0.1       GigabitEthernet
0/0/0
       20.1.1.0/24  Direct  0    0           D   20.1.1.1        Ethernet0/0/0
       20.1.1.1/32  Direct  0    0           D   127.0.0.1       Ethernet0/0/0
      127.0.0.0/8   Direct  0    0           D   127.0.0.1       InLoopBack0
      127.0.0.1/32  Direct  0    0           D   127.0.0.1       InLoopBack0

see R2 Routing table ：

[R2]display ip routing-table  // View routing table 
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Tables: Public
         Destinations : 9        Routes : 9        

Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface

        0.0.0.0/0   Static  60   0          RD   10.1.1.1        GigabitEthernet  // This is the default route 
0/0/0
       10.1.1.0/24  Direct  0    0           D   10.1.1.2        GigabitEthernet
0/0/0
       10.1.1.2/32  Direct  0    0           D   127.0.0.1       GigabitEthernet
0/0/0
       30.1.1.0/24  Direct  0    0           D   30.1.1.1        Ethernet0/0/0
       30.1.1.1/32  Direct  0    0           D   127.0.0.1       Ethernet0/0/0
       40.1.1.0/24  Direct  0    0           D   40.1.1.1        Ethernet0/0/1
       40.1.1.1/32  Direct  0    0           D   127.0.0.1       Ethernet0/0/1
      127.0.0.0/8   Direct  0    0           D   127.0.0.1       InLoopBack0
      127.0.0.1/32  Direct  0    0           D   127.0.0.1       InLoopBack0

（2）PC1 You can talk to PC2、PC3 Interworking

use PC1 Go to ping PC2 or PC3 Of IP Address , It has been found that ping Through the （ use PC2 perhaps PC3 Go to ping Other hosts in the topology can also ping through ）
notes ： Access to the host IP The first few addresses may appear Request timeout! ( request timeout ) Tips , Normal phenomenon

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5、 Summary

The default route is a special static route , Its network address and subnet mask are all 0;

Generally speaking , The default route can be manually configured by the administrator , Similar to static routing configuration , The difference is that the target address network segment and the target address subnet mask are all replaced by 0 ;

Because the default route is a special static route , So in the routing table , The default route is Proto Fields are also displayed as Static, By default , Routing priority Pre by 60, The routing overhead is 0;

Some dynamic routing protocols can also generate default routes on border routers , Then forward to other routes （ Such as OSPF and IS-IS etc. ）

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