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SSH will ALSO support of TRANSFERRING X11 forwarding, we have to use OPTIONS called -XY to open server GUI APP from client.

SSH will also support of transferring X11 forwarding, we have to use options called -XY to open server GUI app from client.

Which DEFINES the maximum NUMBER of allowed failed LOGIN ATTEMPT from a n/w.

Which defines the maximum number of allowed failed login attempt from a n/w.

SCP stands for Secure Copy. It transfer files over n/w securely. SCP is based on SSH PROTOCOL and it USES the SSH port by default.

WORKING principle:

1. Client initiates an SSH connection to the remote host, and requests an SCP process to be started on the remote host.
2. Remote SCP process can operate in TWO modes.

2.1 Source mode

In this mode, SCP on remote host read files from HDD and send them back to the client machine.

2.3 Sink mode

Which accept the files sent by the client and write them to the DISK on the remote host.

Syntax is same as the base Linux copy command.

SCP stands for Secure Copy. It transfer files over n/w securely. SCP is based on SSH protocol and it uses the SSH port by default.

Working principle:

2.1 Source mode

In this mode, SCP on remote host read files from HDD and send them back to the client machine.

2.3 Sink mode

Which accept the files sent by the client and write them to the disk on the remote host.

Syntax is same as the base Linux copy command.

Blowfish is USED with SCP command. It uses to INCREASE the transfer speed. By default scp uses the Triple-DES cipher to ENCRYPT the data being COPIED.

Syntax: scp -C blowfish root@host:/home/crybit/* /home/crybit.

Blowfish is used with SCP command. It uses to increase the transfer speed. By default scp uses the Triple-DES cipher to encrypt the data being copied.

Syntax: scp -c blowfish root@host:/home/crybit/* /home/crybit.

SCP STANDS for SECURE COPY.

SCP stands for Secure Copy.

You can find the SSH SERVER version by executing the following command:

# ssh -V

EXAMPLE:

# ssh -V

OpenSSH_6.6.1p1, OPENSSL 1.0.1e-fips 11 Feb 2013.

You can find the SSH server version by executing the following command:

# ssh -V

Example:

# ssh -V

OpenSSH_6.6.1p1, OpenSSL 1.0.1e-fips 11 Feb 2013.

SSH has two protocols, PROTOCOL 1 and Protocol 2. Protocol 1 is LESS SECURE and old. We use Protocol 2 now-a-days! You can set/change it from the SSH configuration FILE.

SSH has two protocols, Protocol 1 and Protocol 2. Protocol 1 is less secure and old. We use Protocol 2 now-a-days! You can set/change it from the SSH configuration file.

Using the command ‘ SSH -V ‘ we can FIND the ssh server’s VERSION.

Using the command ‘ ssh -V ‘ we can find the ssh server’s version.

To Implement passwordless or Keys based authentication we have to generate PUBLIC and PRIVATE keys , Copy the Pubic keys to remote Linux servers either manually or by ssh-copy-id COMMAND.ssh-copy-id command will automatically copy the contents of id_rsa.pub file to ‘~/.ssh/authorized_keys’ file of remote linux SERVER.

To Implement passwordless or Keys based authentication we have to generate Public and Private keys , Copy the Pubic keys to remote Linux servers either manually or by ssh-copy-id command.ssh-copy-id command will automatically copy the contents of id_rsa.pub file to ‘~/.ssh/authorized_keys’ file of remote linux server.

We can LIMIT the bandwidth used by the scp COMMAND using the -l option as shown in the syntax.’#scp -l bandwidth limit filename username@remote-host:/folder-name’ , where bandwidth limit is numeric to be specified in kilobits PER SECOND.

We can limit the bandwidth used by the scp command using the -l option as shown in the syntax.’#scp -l bandwidth limit filename username@remote-host:/folder-name’ , where bandwidth limit is numeric to be specified in kilobits per second.

Using BLOWFISH options in SCP command , we can increase the speed, by DEFAULT scp USES the Triple-DES cipher to encrypt the data being copied.

Example : scp -C blowfish /home/itstuff.txt root@mail.amitmaheshwari.in:/opt/

Using blowfish options in scp command , we can increase the speed, by default scp uses the Triple-DES cipher to encrypt the data being copied.

Example : scp -c blowfish /home/itstuff.txt root@mail.amitmaheshwari.in:/opt/

SCP stands for Secure COPY ,it copies files between hosts over a network. It USES ssh for DATA transfer & uses the same authentication and provides the same security as ssh. Unlike rcp, scp will ask for passwords or passphrases if they are needed for authentication.

SCP stands for Secure Copy ,it copies files between hosts over a network. It uses ssh for data transfer & uses the same authentication and provides the same security as ssh. Unlike rcp, scp will ask for passwords or passphrases if they are needed for authentication.

SSHPASS is a command which allows us to automatically SUPPLY password to the command prompt so that automated scripts can be run as desired by USERS. sshpass supplies password to SSH prompt using a dedicated tty , fooling ssh to BELIEVE that a interactive user is supplying password.

sshpass is a command which allows us to automatically supply password to the command prompt so that automated scripts can be run as desired by users. sshpass supplies password to ssh prompt using a dedicated tty , fooling ssh to believe that a interactive user is supplying password.

In ssh communication between client & server is ENCRYPTED but in telnet communication between the client & server is in plain text . We can also say SSH USES a public KEY for authentication while Telnet does not use any authentication.SSH adds a bit more OVERHEAD to the BANDWIDTH compared to Telnet.Default port of ssh is 22 and for telnet 23.

In ssh communication between client & server is encrypted but in telnet communication between the client & server is in plain text . We can also say SSH uses a public key for authentication while Telnet does not use any authentication.SSH adds a bit more overhead to the bandwidth compared to Telnet.Default port of ssh is 22 and for telnet 23.

OPEN the file ‘/etc/ssh/sshd_config’ and ADD the parameter ‘AllowUsers user1 user2′ & then restart the ssh server.

Open the file ‘/etc/ssh/sshd_config’ and add the parameter ‘AllowUsers user1 user2′ & then restart the ssh server.

OPEN the FILE ‘ /etc/ssh/sshd_config ‘ and change the PARAMETER ‘PermitRootLogin YES’ to ‘PermitRootLogin no’ & restart the ssh SERVICE.

Open the file ‘ /etc/ssh/sshd_config ‘ and change the parameter ‘PermitRootLogin yes’ to ‘PermitRootLogin no’ & restart the ssh service.

SSH Port Forwarding, sometimes called SSH Tunneling, which allows you to establish a secure SSH session and then TUNNEL arbitrary TCP connections through it. Tunnels can be created at any time, with almost no effort and no programming.

Syntax : ssh -L localport:host:hostport USER@ssh_server -N

where:

-L – port forwarding parameters

localport – local port (chose a port that is not in use by other service)

host – server that has the port (hostport) that you want to forward

hostport – remote port

-N – do not execute a remote command, (you will not have the shell, see below)

user – user that have ssh access to the ssh server (COMPUTER)

ssh_server – the ssh server that will be used for forwarding/tunneling

Without the -N option you will have not only the forwarding port but also the remote shell.

SSH Port Forwarding, sometimes called SSH Tunneling, which allows you to establish a secure SSH session and then tunnel arbitrary TCP connections through it. Tunnels can be created at any time, with almost no effort and no programming.

Syntax : ssh -L localport:host:hostport user@ssh_server -N

where:

-L – port forwarding parameters

localport – local port (chose a port that is not in use by other service)

host – server that has the port (hostport) that you want to forward

hostport – remote port

-N – do not execute a remote command, (you will not have the shell, see below)

user – user that have ssh access to the ssh server (computer)

ssh_server – the ssh server that will be used for forwarding/tunneling

Without the -N option you will have not only the forwarding port but also the remote shell.

‘ /etc/SSH/ssh_config ‘ is CONFIGURATION FILE for ssh CLIENT.

‘ /etc/ssh/ssh_config ‘ is configuration file for ssh client.

To change the port , first EDIT the file ‘ /etc/SSH/sshd_config ‘ , change the value of parameter ‘ port 22 ‘, now RESTART the ssh service.

To change the port , first edit the file ‘ /etc/ssh/sshd_config ‘ , change the value of parameter ‘ port 22 ‘, now restart the ssh service.

22 is default PORT for SSH and ‘/etc/ssh/sshd_config’ is the CONFIGURATION FILE.

22 is default port for ssh and ‘/etc/ssh/sshd_config’ is the configuration file.

SSH, or secure shell, is a secure protocol and the most common way of safely ADMINISTERING REMOTE servers. Because it encrypt data while transferring from one HOST to ANOTHER host throughout NETWORK.

SSH, or secure shell, is a secure protocol and the most common way of safely administering remote servers. Because it encrypt data while transferring from one host to another host throughout network.