fedora linux

The Blue Screen of Death (BSoD) is used for the error screen displayed by Microsoft Windows, after encountering a critical system. Linux / UNIX like operating system may get a kernel panic. It is just like BSoD. The BSoD and a kernel panic generated using a Machine Check Exception (MCE). MCE is nothing but feature of AMD / Intel 64 bit systems which is used to detect an unrecoverable hardware problem.

Program such mcelog decodes machine check events (hardware errors) on x86-64 machines running a 64-bit Linux kernel. It should be run regularly as a cron job on any x86-64 Linux system. This is useful for predicting server hardware failure before actual server crash.

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Linux kernel is the central component of Linux operating systems. It is responsible for managing the system’s resources, the communication between hardware and software and security. Kernel play a critical role in supporting security at higher levels. Unfortunately, stock kernel is not secured out of box. There are some important Linux kernel patches to secure your box. They differ significantly in how they are administered and how they integrate into the system. They also allow for easy control of access between processes and objects, processes and other processes, and objects and other objects. The following pros and cons list is based upon my personal experience.

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The round-robin database tool aims to handle time-series data like network bandwidth, temperatures, CPU load etc. The data gets stored in round-robin database so that system storage footprint remains constant over time. Lighttpd comes with mod_rrdtool to monitor the server load and other details. This is useful for debugging and tuning lighttpd / fastcgi server performance.

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Usually, you do not need to setup an email server under Linux desktop operating system. Most GUI email clients (such as Thunderbird) supports Gmail POP3 and IMAP configurations. But, how do you send mail via the standard or /usr/bin/mail user agents or a shell script? Programs such as sendmail / postfix / exim can be configured as a gmail smarthost but they are largely overkill for this use.

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MAC Filtering (layer 2 address filtering) refers to a security access control methodology whereby the 48-bit address assigned to each network card is used to determine access to the network. Iptables, pf, and IPFW can block a certain MAC address on a network, just like an IP. One can deny or allow from MAC address like 00:1e:2a:47:42:8d using open source firewalls. MAC address filtering is often used to secure LAN or wireless network / devices. Is this technique effective?

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tail is one of the best tool to view log files in a real time (tail -f /path/to/log.file). The program MultiTail lets you view one or multiple files like the original tail program. The difference is that it creates multiple windows on your console (with ncurses). This is one of those dream come true program for UNIX sys admin job. You can browse through several log files at once and do various operations like search for errors and much more.

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This example shows how you might set up a large internet facing FTP site for distributing file or software updates. The emphasis will be on security and performance. VSFTPD will make sure only world-readable files and directories are served to the world via anonymous / ftp account. You force to originates FTP port connections from a secure port – so users on the FTP server cannot try and fake file content. You will hide the FTP server user IDs and just display ftp in directory listings. This is also a performance boost. Set a 40000-60000 port range for passive connections. This will help firewall setup.

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