Q. I’ve CentOS Linux cpanel server. I’d like to turn off SFTP server but only allow SSH for root user. How do I trun off sftp server?
A. OpenSSH / sshd reads configuration data from /etc/ssh/sshd_config. The file contains keyword-argument pairs, one per line. Lines starting with â€˜#â€™ and empty lines are interpreted as comments. Configures an external subsystem such file transfer daemon (SFTP) done through this file only. Arguments should be a subsystem name and a command to execute upon subsystem request. The command sftp-server implements the â€œsftpâ€ file transfer subsystem. sftp-server is a program that speaks the server side of SFTP protocol. sftp-server is not intended to be called
directly, but from sshd using the Subsystem option.
Disable / Turn off sftp server
Open /etc/ssh/sshd_config file:
# vi /etc/ssh/sshd_config
Find line that read as follows:
Subsystem sftp /usr/lib/openssh/sftp-server
Remove or comment out line by prefixing #:
# Subsystem sftp /usr/lib/openssh/sftp-server
Save and close the file. Restart sshd service:
# /etc/init.d/sshd restart
need to provide a remote access to my Ubuntu Linux based server. How do I start / stop OR restart the ssh server under Ubuntu Linux operating system using command line options?
ow do I block access to root user over ssh session on my Linux server? How can I block root user log in over ssh based session for security reasons?
Q. Iâ€™ve HP-UX installed on my HP UX UNIX server. But Iâ€™m not able to start or restart the OpenSSH ssh server. How do I stop or restart sshd under HP-UX?
A. HP-UX Secure Shell uses Pluggable Authentication Module for password authentication. Server configuration file is located at /opt/ssh/etc/sshd_config.
HP-UX SSHD System Startup and Shutdown script:
System startup configuration file
Stop HP UX SSH Service
Type the command:
# /sbin/init.d/secsh stop
Start HP UX SSH Service
Type the command:
# /sbin/init.d/secsh start
hen I run ssh command I get an error which read as follows:
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
Please contact your system administrator.
Add correct host key in /home/user/.ssh/known_hosts to get rid of this message.
Offending key in /home/user/.ssh/known_hosts:1
RSA host key for ras.mydomain.com has changed and you have requested strict checking.
Host key verification failed.
How do I get rid of this message?
know FTP is insecure, how do I securely copy files across a network computer? My network has Windows and Linux systems and how to copy files from one machine to another using ssh? Continue reading “Linux or UNIX securely copy files across a network computer”
Q. I have just installed Ubuntu 6.06 and I would like to allow remote login to my system from home via ssh. How do I install and configure SSH server?
A. OpenSSH is a FREE version of the SSH connectivity tools that technical users of the Internet rely on. Users of telnet, rlogin, and ftp may not realize that their password is transmitted across the Internet unencrypted, but it is. OpenSSH encrypts all traffic (including passwords) to effectively eliminate eavesdropping, connection hijacking, and other attacks. Additionally, OpenSSH provides secure tunneling capabilities and several authentication methods, and supports all SSH protocol versions.
Ubuntu SSHD Installation
Type the following two command to install both ssh client and server:
# sudo apt-get install openssh-server openssh-client
To be frank your server is ready by default. Just test it from your home computer or from same system with the command:
# ssh localhost
# ssh user@your-server-ip-address
How do I use ssh client?
Assuming that your server hostname is userver.mydomain.com and username is vivek, you need to type the following command:
# ssh email@example.com
To stop ssh server, enter:
# sudo /etc/init.d/ssh stop
To start sshs server, enter:
# sudo /etc/init.d/ssh start
To restart ssh server, enter:
# sudo /etc/init.d/ssh restart