How to verify network status and switch operation using basic utilities: Ping, SSH and telnet

Certification: Cisco CCIE Routing and Switching - Cisco Certified Internetwork Expert Routing and Switching

In order to understand the verification and the status of a particular network one has to understand first what ping, SSH and telnet are all about and their importance when it comes to network utility.


Ping is an administration utility that is present in a given computer network and whose function is to test how a host on a particular internet protocol is reached and it also measures the time taken to send a message from the host to its destination and vice versa. This is always accomplished by simply sending an internet control message protocol that are packets to the hosts that needs that particular information, as this is done it records the time taken to transmit and receive that message and also records any time loss and particularly if there has been any packet loss as the process took place.

In addition, this network utility has other switches that act like command lines that are usually used when there is a special occurrence of an activity. These activities may include specification of a new packet size, when there is an automatic operation that occurs repeatedly and stamping of the time taken during a certain process. For Ping to function appropriately, the host is usually required to process an echo request and in turn issue what is known as an echo reply for the operation to be completed successfully.

To be able to analyze its results this utility usually completes first its ping probes using the shortest possible time using a measurement known as the standard deviation. Its message tone is made up of the ICMP packet that has the following contents an IP header that in most cases is blue in color and set to a service equivalent to zero, ICMP header that is red in color and consists of a message size of 8 bits, a check sum of 16 bits and a code of 8 bits. Other contents are a payload used to differentiate the answers received and messages sent and it should have a maximum transmission unit of the network and a data transportation unit.

How Ping works

The host is required to have an echo request and an echo reply path and this summarizes how Ping operates. The echo request that is an ICMP message is the data expected to be sent to the echo reply and in turn the host has to reply to the massage and send. The identifier in this case uses a sequence number to read and analyze the message that has been sent and is always reset only when data is entirely completed.

The echo reply is the massage that is always generated after a message has been received and this feature is far much important especially in routers and all the hosts and the replies are expressed in letter form like S to mean the source route failed. Other replies may include the first contents of the original message and an advantage is that the ping utility can match all its message replies to where the problem originates from.


This protocol version was first designed in the year 1995 and meant to be a network utility that aids in  provision of network services that are entirely secure using SSH client and SSH server programs. There are two versions of the SSH protocol that work in conjunction with each other in different operating systems. It has an encryption that makes it more efficient in rendering services like sending information using data packets over any unsecured network like the internet.

SSH can either use the public or private key pairs to automatically connect to a network and then access the password of that particular network in the internet. SSH also enables users and programs to access the network without having access to any passwords. The thing it does is to ensure that the same person logs in to a particular internet if secured in other words it guards other users from accessing a private network. SSH has a special feature known as the Keygen that is used to produce the required keys n the public and private networks.

The SSH client which is a program, is useful when it comes establishing secure connections in the modern operating systems and in cloud computing in solving connectivity issues and from exposing the virtual machine to risks of unprotected internet. Other uses of SSH include, ensuring secure file transfer, forwarding and tunneling the network ports, in execution of commands in a given host  and for back up purposes.

SSH also has different mechanisms that are used to transfer files and perform its other duties namely; the secure copy, the file transfer protocol and the RCP protocol.

Due to the fact that has proven to be more efficient there are several enhancements made to it so as to further improve its performance and the enhancement are in these areas; ECDSA, UMAC and in the ECDH.


It is also a network protocol that is commonly used in the local area networks and the internet to promote communication that is purely interactive and user friendly. In other words it is software that uses data that is band oriented to all computer platforms. One of the common features in telnet is the telnet data. The data in here is usually transferred as it is to the host through the telnet client. It is used to establish a session known as the raw TCP session that ensures that there is proper functionality of the networks.

Telnet is also used in network services that involve debugging in the following areas IRC, HTTP, POP3, SMTP and IRC servers and its purpose is to offer commands and examine all the responses.

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