Hello everyone, my network worker friends
It's been a long time since I talked with you about Cisco equipment.
Although in the current general direction, the equipment used by enterprises is becoming more and more localized, and more and more people are learning from manufacturers such as Huawei and H3C.
But it is undeniable that Cisco is still the big brother of manufacturers.
In terms of switches and routers, Cisco still has a large global market share.
At present, some foreign companies or original manufacturers of large manufacturers still have some talent positions that only recruit Cisco-oriented network workers. They are entangled in which manufacturer to choose. I suggest you consider it according to your career development.
The most important thing is to practice more in this process and be familiar with the manufacturer's equipment , such as the manufacturer's equipment commands, how many are you familiar with?
I have also shared with you the command collections of major manufacturers before , and here are the ones I want to see:
" The Most Complete Collection of Huawei Device Commands "
" The Most Complete Collection of Cisco Device Commands "
" The Most Complete Collection of Ruijie Device Commands "
" The Most Complete Collection of H3C Equipment Commands "
Talk to you today, when debugging Cisco equipment, what do you think are the most frequently used and most practical commands ?
I'll start with 10!
Today's article reading benefits: "cisco router configuration (practical)"
Fans who want to learn more about Cisco routing technology, please private message me and send the password "Cisco" to get this official Cisco textbook resource to further enhance your technical vision.
01 ？
When using the command line, it is impossible for us to remember all the commands, sometimes we can only remember the beginning of a certain command, then ?the command is very useful at this time.
You can use this command in many ways, such as using it when you don't know what command to enter, to see a list of all possible commands.
For example, you can also use commands when you don't know what the next parameter of the command should be ?.
For example, you can enter show ip ?, and if the router does not require other command parameters, the router will provide <CR>that as the only parameter.
02 debug
This command has many options and cannot work alone, providing detailed debugging output about an application, protocol or service. debug ip routingFor example, you can use the command to debug each time a route is added to or removed from the router .
Note: Debugging can be dangerous because its process takes precedence over all other processes.
The feature can be disabled using no debugcommand or commands.undebug all
03 copy running-configuration startup-configuration
This command saves the configuration currently being modified (in RAM, also known as the running configuration ) to non-volatile RAM (NVRAM), which retains this configuration if power is lost.
In other words, if you edit the router's configuration, do not use this command and reboot the router, those changes will be lost.
copy running-configuration startup-configurationCommands can be abbreviated in copy run startcase the router fails.
04 show interface
This command can display the status of the router's interfaces, this output provides the following, among other things:
- Interface status (up/down) Interface status (up/down)
- Protocol status on the interface interface protocol status
- Utilization
- Errors
- PERSON
This command is essential for troubleshooting routers or switches, and it can also be used by specifying a certain interface, eg sh int g0/0.
05 no shutdown
This command is used to enable the interface and must be used in the interface configuration mode . It is useful for new interfaces and troubleshooting.
from wljslmz When encountering interface problems, you may want to try closing and not closing, of course, to close the interface, you can use it shutdown.
no shutdownAbbreviated as no shut.
06 show version
This command displays the router's configuration registers (essentially router firmware settings for booting), the last time the router was booted, the version of IOS, the name of the IOS file, the model of the router, and the amount of RAM and flash memory on the router.
show versionAbbreviated as sh ver.
07 show ip interface
This command displays detailed information about the configuration and status of the IP protocol and its services on all interfaces.
It also has a more frequently used command: show ip interface brief, which will give a brief status of the interfaces on the router, including their IP addresses, layer 2 status, and layer 3 status. The information is more concise, and sometimes the information displayed by this command is what we want.
08 show ip route
This command is used to display the router's routing table , which is a list of all the networks the router can access, their metrics, and how to get there.
show ip routeAbbreviated as sh ip ro, parameters can be added later, such as all OSPF routes sh ip ro ospf.
To clear the routing table for all routes, execute clear ip route, to clear one of the routes, the command is clear ip route xxxx(where xxxx is the network you want to clear).
09 ？config terminal, enable, interface, and router
Cisco routers have different modes in which only certain things can be displayed or can be changed, and being able to move between these modes is critical to successfully configuring the router.
When you log in, you start in user mode (what the prompt looks like >), and when you enter enable commands you enter privileged mode (what the prompt looks like #).
In privileged mode, you can display anything, but you can't make changes, enter config terminal(shorthand conf t) in this mode to enter global configuration mode (prompt looks like router(config)# ) in this mode, you can change global parameters.
If you want to change parameters on an interface, such as the IP address, use interfacea command (prompt similar to router(config-if)#) to enter interface configuration mode .
Also from global configuration mode, router {protocol}the router configuration can be entered using the command.
To exit a mode, enter a command exit.
10 show running-configuration
This command displays the current configuration of a router, switch, or firewall and is used very frequently.
Every time we want to see what commands have been configured on the current device, we will enter the command without hesitation: sh run, so show running-configurationthe abbreviation is sh run, everyone keep in mind!
Finishing: Lao Yang 丨 10-year senior network engineer, more network workers to improve dry goods, please pay attention to the official account: Network Engineer Club