Tag Archives: Unix

Test firewall with netcat

Overview

“The nc (or netcat) utility is used for just about anything under the sun involving TCP, UDP, or UNIX-domain sockets.
It can open TCP connections, send UDP packets, listen on arbitrary TCP and UDP ports, do port scanning, and deal with both IPv4 and IPv6. Unlike telnet nc scripts nicely, and separates error messages onto standard error instead of sending them to standard output, as telnet does with some.” (NetCat Manual)

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chmod suid sgid sticky bit

Overview

Linux chmod has a few options that can make your life a lot easier when managing a shared storage.
The most needed are chmod suid sgid sticky bit.
Also the impact of each one is different between files and folders.
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tr vs sed – String manipulation commands in Linux/Unix

Overview

tr and sed are very powerful stream and character manipulation commands, Each has its own advantage with string manipulation.
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Linux fg bg commands usage and examples

Overview

Linux fg bg commands usage and examples using CTRL-Z and jobs command.
Move a process between background and foreground modes with paused and running states.
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configure apache

Apache VPS Optimization

Apache VPS Optimization – Memory Usage Tuning

I’ve recently had the need to optimize my VPS plan so it won’t consume that much memory.
The main culprit was Apache with more then a few processes using over 50MB.

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Load Balancing SSH Connections using Pen on CentOS Linux

Overview

Load Balancing SSH Connections using Pen, a load balancer for “simple” tcp based protocols such as http or smtp.
It allows several servers to appear as one to the outside and automatically detects servers that are down and distributes clients among the available servers. This gives high availability and scalable performance.

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Load balancing Remote Desktop Services using Pen

Overview

Load balancing Remote Desktop Services using Pen, a load balancer for “simple” tcp based protocols such as http or smtp.
It allows several servers to appear as one to the outside and automatically detects servers that are down and distributes clients among the available servers. This gives high availability and scalable performance.

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Move Volume to another Aggregate on NetAPP OnTAP 8

Overview

In this tutorial we will be using NetAPP FAS3210 to demonstrate How to Move Volume to another Aggregate on NetAPP OnTAP 8.

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PuTTY Configuration Tips with SSH Connection

Overview

You can find here a few PuTTY Configuration Tips that will save you a lot of time using SSH.
PuTTY is a free and open source terminal emulator application.

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Remote Desktop over SSH using PuTTY

Overview

Connecting to a SSH server as a gateway and not directly to a Remote Desktop PC is a safer way to connect and add another layer of encryption without losing performance,
this way you can connect to any client behind a firewall as long as you have port 22 open to your SSH server.
Using Windows Remote Desktop over SSH connection is a very simple task to perform using PuTTY.
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Remote Desktop over SSH using Tunnelier

Overview

Bitvise Tunnelier makes it easier to Use Windows Remote Desktop over SSH connection.
Connecting to a Secure Shell server as a gateway and not directly to a windows PC, is a safer way to connect and add another layer of encryption.
This way you can connect to any client behind a firewall as long as you have port 22 open to your SSH server.

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Schedule tasks on Linux using Cron

Overview

Cron is the time-based job scheduler in Unix-like computer operating systems.
Cron enables users to schedule jobs (commands or shell scripts) to run periodically at certain times or dates.
It is commonly used to automate system maintenance or administration, though its general-purpose nature means that it can be used for other purposes.
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