Wake-on-LAN (WOL) is an Ethernet networking standard that allows a server to be turned on by a network message. You need to send ‘magic packets’ to wake-on-lan enabled ethernet adapters and motherboards, in order to switch on the called systems. Make sure you connect the NIC (eth0 or eth1) with the motherboard, and enable the WOL function in the BIOS. This is a quick guide to enable WOL under RHEL / Fedora / CentOS / Debian / Ubuntu Linux.
The last time I wrote about CDN, I wrote about how to configure CDN for wordpress to speed up your wordpress blog to display content to users faster and more efficiently. However, a few regular readers like to know how to configure the Amazon CDN or other CDN network to use with Vbulletin forum software. In this quick tutorial, I will explains how to configure Vbulletin, Apache/Lighttpd webserver, Bind dns server to use a CDN to distribute your common files such as css, js, user uploaded files and lighten load on your web server.
The sar command collect, report, or save UNIX / Linux system activity information. It will save selected counters in the operating system to the /var/log/sa/sadd file. From the collected data, you get lots of information about your server:
- CPU utilization
- Memory paging and its utilization
- Network I/O, and transfer statistics
- Process creation activity
- All block devices activity
- Interrupts/sec etc.
sar output can be used for identifying server bottlenecks. However, analyzing information provided by sar can be difficult, so use kSar, which can take sar output and plot a nice easy to understand graph over period of time.
Today, Google has announced the launch of their free DNS resolution service. Many ISPs and 3rd party provider such as OpenDNS snoops around or send traffic to ad servers. However, Google promises not to play with end users and send the exact response his or her computer expects without performing any blocking, filtering, or redirection that may hamper a user’s browsing experience. In other words Google will not hijacking your traffic on non-existent domain name and it will follow strict RFC standard.
Securing your Linux server is important to protect your data, intellectual property, and time, from the hands of crackers (hackers). The system administrator is responsible for security Linux box. In this first part of a Linux server security series, I will provide 20 hardening tips for default installation of Linux system.
BIND 9 is an implementation of the Domain Name System (DNS) protocols. named daemon is an Internet Domain Name Server for UNIX like operating systems. Dynamic update messages may be used to update records in a master zone on a nameserver. When named receives a specially crafted dynamic update message an internal assertion check is triggered which causes named to exit. An attacker which can send DNS requests to a nameserver can cause it to exit, thus creating a Denial of Service situation. configuring named to ignore dynamic updates is NOT sufficient to protect it from this vulnerability. This exploit is public. Please upgrade immediately.