[comonforall]

when do we use the command ping 127.0.01 and ping 209.166.161.121

I guess the first one we use to check if our network adaptor is working or not.

 

[etaf]

you usually ping the default gateway of a router and then a name like google and then an IP address to see if there is a dns issue - not sure what the IP is of - looks like a broadband company
IP Address: 209.166.161.121
DNS server

I use the IP address for TSG website -
but could use the IP of this forum
67.228.57.82

the only reason i do that - is you can out the ip into a web browser and it should display the web page (although if there is a DNS issue will not display all the images etc correctly )

 

[epshatto]

ping 127.0.0.1 is the command used to test the local computer's connectivity.

There should be 0% packet loss. If the packet loss is 100% (it would be one or the other), then the local computer's network adapter is not functioning.

127.0.0.1 is a loopback address; ie, 127.0.0.1 will always refer to the local computer from which the command is run.

An example of a situation in which a loopback test is appropriate would be on a network that refuses to print to a network printer when other computers can, for example. Or if the local computer won't show up on a network and there's no sign of a network-wide problem.

 

[comonforall]

Thanks all,
@ephsatto
How we can find if the packet loss is 100% or 0%

 

[epshatto]

It will tell you in the results of the ping.

Whenever you run a ping command, there will be 4 packets sent to the specified IP address (unless you use a particular switch which sends packets continuously until manually stopped). PING by itself sends 4. It will tell you the total time it took for the packets to be received and replied to, and what the percentage of loss is.

Ping statistics for 127.0.0.1:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),