Sandeep kalathil

Iam a System Engineer working in Cochin , Interested in Linux and Windows servers and happy to share knowledge that i have gained through my day to day work.

Secure file transfer from Windows to Linux using RSA key

PSCP is a command line application which is a free implementation  of scp for win 32 platform  . This tool is used for securely copying between computer systems. It uses the SSH (secure shell) protocol, which makes it impossible for other people on the network to snoop on your password or on the data you are transferring. PSCP can run …

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Open Source SSH Connection Manager

Since the time i started to work on Ubuntu ( feels good that i left windows) i was searching for an application which works likes ( at least in close proximity) Putty connection manager. After a lot of search i came across an application called Gnome Connection Manager. It is a tabbed ssh connection manager for GTK+ environments. It has …

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Redhat linux hardening tips & bash script

From the time a servers goes to live environment its prone to too many attacks from the hands of crackers (hackers) also as a system administrator you need to secure your Linux server to protect and save your data, intellectual property, and time here server hardening comes into effect. Securing a server is much different than securing a desktop computer …

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Linux Logs that an Administrator need to Monitor

Linux maintains a record of a various logs that helps a administrator to keep track of important events including system error messages, system startups, and system shutdowns. The logs are in ASCII text format and hence can be viewed with a text editor. The centralized logging is provided by two daemons are syslogd and klogd. Almost all the logfiles generated …

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Prevent accidental reboots in Linux Servers

CTRL+ATL+DELETE will be the most commonly used shortcut key when we work on windows . Watch out that you never use this key (CTRL+ATL+DELETE) on linux server. The default Linux installation treats CTRL+ATL+DELETE command to immediately reboot the Linux system without any warning signals. To avoid this to happen we need to edit  the inittab file /etc/inittab The inittab file …

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Disabling runlevel system services on Linux Servers

When Linux server boots up a large amount of services keeps running in its background . Some services are essential to the operation of your server, while other services are considered non-essential and will cause no problems to your server by disabling them.  Some services takes a lot of time and may affect the working of some of your applications. …

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Securing SSH in Linux Servers

SSH security has to be taken care when Linux server is up and running. Most administrators tend to install an SSH server and leave it at its default settings, typically to allow password authentication and root logins . There are few parameters in /etc/ssh/sshd_config which can be changed to securing SSH. Open /etc/ssh/sshd_config and add the below line PermitRootLogin no …

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OpenSSH deny access for users groups and hosts

In an organization where when a server goes live an administrator would need to create a users with variable privileges . Some users will have special permissions with root credentials. We here are trying to block that privileged users from direct ssh log in. To Deny a User Open /etc/ssh/sshd_config file: # vi /etc/ssh/sshd_config Append following names (directives): DenyUsers username …

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