Comprehensively Summarize the Common Usage of The PING Command—CCIE Dumps

CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps

As a simple way for network engineers to use, the ping command is the most commonly used tool in our daily life, which can be used to check if the network connects, delays, loses packages or has other common problems. We use it at every time. We keep asking ourselves every day：”Why not connect? Why can?? And How this can connect?”But do you really understand ping? Today we will take you to understand all the features you know and you don’t know about the use of the ping.

Basic operations of PING

Ping is most commonly used to test the connectivity with one host. What we usually can see is like this:

Ping under the Windows commands default to send four ICMP packages, including three common values:

Bytes：Refers to the ICMP packages size we use to test connectivity

Time：This time is the response time of the target host

TTL（Time to Live）: TTL under the Windows default set to 128 The biggest can be set to 255.  After hopping its routing minus one and date packages will be discarded when TTL becomes zero.

In actual use, we may wish to change these values according to our needs to use ping comfortably. Then the following command parameters appear.

CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps

1. Send many packages (ping -n ping -t)

Ping command in the Windows the default send only 4 ICMP packages. However, when sometimes we want to test if in a period of time it will lose packages, we must input the command again and again, or the average response time we want to know about the host, is only four packages of data not reliable enough? So we can use the -n command to specify the number of packages to be sent.

We can see ping has sent 10 date packages according to the result that we want, and it will automatically help you calculate data. If we want to observe longer, we can use -t parameters to ping continuously and press ctrl+c to stop it.

• 2. Modify the package size and TTL（ping -l ping -i）

 Whatever we are likely to encounter every day. Sometimes we find that the default TTL128 is not enough bigger to test network；sometimes we need smaller TTL for special situations. This is the time for the -l and – i parameters, among them the maximum package– 65500 bytes and TTL range– 1-255.

• 3. Analysis IP according to the DNS and the host names according to IP（ping -a）

Ping command can directly ping the domain name, which can help us to check whether a domain name is successfully parsed and accessed.

But sometimes we can also use – a parameter to check the IP address, so we often can see the host name, but sometimes we also can reverse domain name.

• 4. Use the ping command to track routing（ping -r） Add – r parameter at the ping command can show the tracked routing 

Contrast to the tracert, its benefit is with parameters such as response time, and the disadvantage is that the biggest support is only 9 jump, which won`t have ideal effect in the public network.

5. use “for statement” to avoid duplication of effort

Think of if we want to test a department`s hundreds of thousands of node connectivities, putting ping one by one is dull and heavy. So we can do this:

The three numbers –1，1，255 in the bracket means starting from 1, each time adding 1 to 255. So we can according to the actual situation to deal flexiblely. For example, when we want to test the even IP address that we can write the  (2,2,254). This way is very convenient.

CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps

Common faults of PING

1. Request time out is most common.  

When ping received no reply will time out.This situation usually is resulted by without routing or back pack. Of course, such as some 2-level failures may also cause this phenomenon, so we should according to the specific circumstances of illness to troubleshoot.

• 2.Ttl expired in transit  

This situation is usually caused by TTL running out in the process of transmission. So we can change the -i parameter to increase TTL value to test again and consider whether there is a routing loop in the network.

• destination unreachable

This is more common. Generally it is a device without routing paths or do the related strategy, we just need to tracert target address and see where tracking routing is broken, thus we can pinpoint the problems commonly.

The above is several common echos, of course, there are a lot of echos and pings. We sort out here in the following table for your reference.

CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps CCIE Dumps