Apache Security Update – a flaw In Apache can be used to carry out DoS. Slowloris is a new Apache DoS tool which can use slow Internet links to bring down Apache servers, rather than flooding networks. Most D/DoS tool requires faster net connections but this tool works with minimal bandwidth. This tool can lead to a DoS attack on Apache 1.x, 2.x, dhttpd, GoAhead WebServer, and Squid, while MS IIS6.0, IIS7.0, and lighttpd are confirmed not vulnerable to this attack.
Fedora Linux version 11 has been released and available for download ( jump to download link ). Fedora Linux is a community-based Linux distribution. Fedora is sponsored by Red Hat, Inc.
One of Fedora’s main objectives is not only to contain free and open source software, but also to be on the leading edge of such technologies. Fedora 11, codenamed “Leonidas”, was released on June 9, 2009. The features include ext4, a 20-second startup, and the latest GNOME, KDE and XFCE releases. Firefox 3.5 and Thunderbird 3’s latest pre-releases are available as well.
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How do I find out if a given PCI hardware is supported of by the current CentOS / Debian / RHEL / Fedora Linux kernel?
You can easily find out find out if a given piece of PCI hardware such as RAID, network, sound, graphics card is supported or not by the current Linux kernel using the following utilities under any Linux distributions.
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.
The ss command is used to show socket statistics. It can display stats for PACKET sockets, TCP sockets, UDP sockets, DCCP sockets, RAW sockets, Unix domain sockets, and more. It allows showing information similar to netstat command. It can display more TCP and state information than other tools. It is a new, incredibly useful and faster (as compare to netstat) tool for tracking TCP connections and sockets. SS can provide information about:
- All TCP sockets.
- All UDP sockets.
- All established ssh / ftp / http / https connections.
- All local processes connected to X server.
- Filtering by state (such as connected, synchronized, SYN-RECV, SYN-SENT,TIME-WAIT), addresses and ports.
- All the tcp sockets in state FIN-WAIT-1 and much more.
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.
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.
Vsftpd (Very Secure FTP Daemon) is an FTP server for UNIX-like systems, including CentOS / RHEL / Fedora and other Linux distributions. It supports IPv6, SSL, locking users to their home directories and many other advanced features.
In this guide you will learn:
- Setup vsftpd to provide FTP service.
- Configure vsftpd.
- Configure Firewalls to protect the FTP server.
- Configure vsftpd with SSL/TLS.
- Setup vsftpd as download only anonymous internet server.
- Setup vsftpd with virtual users and more.
Applications that perform a lot of memory accesses (several GBs) may obtain performance improvements by using large pages due to reduced Translation Lookaside Buffer (TLB) misses. HugeTLBfs is memory management feature offered in Linux kernel, which is valuable for applications that use a large virtual address space. It is especially useful for database applications such as MySQL, Oracle and others. Other server software(s) that uses the prefork or similar (e.g. Apache web server) model will also benefit.
The CPU’s Translation Lookaside Buffer (TLB) is a small cache used for storing virtual-to-physical mapping information. By using the TLB, a translation can be performed without referencing the in-memory page table entry that maps the virtual address. However, to keep translations as fast as possible, the TLB is usually small. It is not uncommon for large memory applications to exceed the mapping capacity of the TLB. Users can use the huge page support in Linux kernel by either using the mmap system call or standard SYSv shared memory system calls (shmget, shmat).