- #HOW TO USE TELNET TO SSH FULL#
- #HOW TO USE TELNET TO SSH PASSWORD#
- #HOW TO USE TELNET TO SSH SERIES#
Next, you must enable an SSH version and apply it to the VTY Lines. Also, demonstrated in example 8 is the crypto key zeroize command which will erase the key. This is useful for those that don’t know which key size may be necessary for a given application. Example 7 displays the more interactive version of this command.
#HOW TO USE TELNET TO SSH FULL#
Examples 6 and 7 display two different ways to use the command it’s configuration for the rsa keys.Įxample 6 is the full blown way of configuring the general key.
This is done with the command crypto key generate rsa. Example 5 displays creating a unique (local) domain-name for the router.Īfter this is done you must generate a key. This key is derived from the ip domain-name command. The next command is mandatory, SSH needs to have a key for its connection. The first necessary command is to configure a local user database as illustrated in example 2. SSH also uses a more commands for setup in comparison to telnet. SSH runs on TCP protocol number 22 and unlike telnet, does include encryption. The other common application for remote access to Cisco routers and switches is Secure Shell protocol (SSH). (Ok, it says "cisc", but frame 66 contains the letter "o" so with work, a skilled hacker or even a novice can see these messages sent in clear text.)
#HOW TO USE TELNET TO SSH PASSWORD#
The frame that was captured shows inside the telnet data, the password cisco being sent in one of the messages. As shown, I have a Wireshark looking at the messages that are going between these two routers. Notice that I created an enable password of cisco on ROUTER1.Įxample 4 displays the vulnerability of telnet. In example 3 you can see that the router on the right (ROUTER 0) is telneting to the router on the left (ROUTER 1). Eavesdroppers can easily discover messages that are passed between two devices using telnet, in fact programs such as Wireshark or Ethereal can see the passwords inside the telnet packets. In other words, it has no encryption mechanism. However, telnet doesn’t have any type of confidentiality. Telnet uses TCP port number 23 and is one of the most commonly used protocols for remote access. Second, by default Telnet is associated with the VTY lines. In either case, if someone need to gain access to this device they will have to login with the authentication type that was specified.
The other option (shown in example 2) is to use the local user database. In example 1 you will see our basic access to setup the default telnet lines to this router.Īs you can see, a basic password has been configured. (This seems obvious but it will be quite useful later in a future discussion.) Additionally, for the access lines you must configure either a line password, or local user database for the way to authenticate to the device. Both protocols can be used for remote access but their differences are important to any network technician or engineer.įirst, to gain remote access to the Virtual Terminal Teletype lines (VTY), a router or switch must be reachable with a given routed protocol. We also discussed configuring security features such as banners that can be used for legal purposes.įor this discussion we will compare Telnet and Secure Shell protocol (SSH). These commands included cosmetic commands such as logging synchronous and exec-timeout that can be configured on the console port.
#HOW TO USE TELNET TO SSH SERIES#
In our last blog series we discussed multiple access commands that can be configured on a router or a switch.
0 kommentar(er)
