Linux TCP Tuning

The aim of this post is to point out potential kernel tunables that might improve network performance in certain scenarios. As with any other post on the subject, make sure you test before and after you make an adjustment to have a measurable, quantitative result. For the most part, the kernel is smart enough to detect and adjust certain TCP options after boot, or even dynamically, e.g the Sliding Window size etc.

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How to connect to Cisco routers using Minicom

In this tutorial, I am going to show you how to connect to a Cisco router by using Minicom terminal. I am using Linux by the way. If you’re
using Window$, besides the suggestion to dump it out and change it with Linux, I think hyperterminal is still your best option. Just Google it: “How to hyperterminal cisco router”. Continue reading

Understanding logrotate utility

Logs are useful when you want to track usage or troubleshoot an application. As more information gets logged, however, log files use more disk space. Over time a log file can grow to unwieldy size. Running out of disk space because of a large log file is a problem, but a large log file can also slow down the process of resizing or backing up your virtual server. Additionally, it’s hard to look for a particular event if you have a million log entries to skim through. So it’s a good idea to keep log files down to a manageable size, and to prune them when they get too old to be of much use. Continue reading

Linux audit files to see who made changes to a file

This is one of the key questions many new sys admin ask:

How do I audit file events such as read / write etc? How can I use audit to see who changed a file in Linux?

The answer is to use 2.6 kernel’s audit system. Modern Linux kernel (2.6.x) comes with auditd daemon. It’s responsible for writing audit records to the disk. During startup, the rules in /etc/audit.rules are read by this daemon. You can open /etc/audit.rules file and make changes such as setup audit file log location and other option. The default file is good enough to get started with auditd. Continue reading

How Do I Access or Mount Windows/USB NTFS Partition in RHEL/CentOS/Fedora

How to Mount Windows NTFS Partition in Linux

First you need to enable EPEL (Extra Packages for Enterprise Linux) Repository. You may refer the article on how to enable EPEL Repository under RHEL, CentOS and Fedora systems.

To mount any NTFS based filesystem, you need to install a tool called NTFS3G. Before heading up for installation let’s understand NTGS3G.

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