Java programming language is most popular programming languages (Tiobe Index)but Java applications are monster and eating computing resources easily if codes are not optimized and application not profiled. Monitoring Java applications has overhead on a system and in most of scenarios, test environments are different than production environments.
Red Hat Satellite is a system management software for Red Hat Enterprise Linux that provided by Red Hat. Red Hat Satellite is an open source software but you have to pay for subscriptions, if you want access to that. Red Hat Satellite or any other system management software is necessary for medium and large companies to provision, manage and keep update physical and virtual servers.
What do you need for Small and Medium-Sized Enterprise businesses in IT department? Directory service, Mail service, Firewall. Anti-Spam, and many other services. You have to pay for each service if you want to have proprietary software such as Microsoft’s products. When we are talking about cost, open-source software will help you to reduce costs. Please consider that open-source software has cost for you but it will lower than closed-source software.
Why We Should Mitigate SSH Based Attack SSH (Secure Shell) is a most popular remote protocol. SSH allows remote login and execute commands. That providing secure way to login and run commands on remote systems in unsecured networks. Telnet replace with SSH cause of offering more security. But SSH has some weaknesses, in order to reducing SSH based attack, those weaknesses can be mitigated. There is some hardening tips, the tips turn your SSH server into a rock solid communication daemon. Best SSH Hardening Tips In the next minutes, we’ll review 15 solutions from best SSH hardening tips. Each hardening tip will a shield against SSH based attacks. Most of the tips are SSH configurations, some of those tips are different on Linux distributions, so please check the configurations on your distribution documents as well. Also Windows 10 and Windows 2019 have OpenSSH server by adding Win32-OpenSSH to Windows, so read Microsoft documents as well. You must restart SSH server daemon after applying configurations. 1. Custom SSH Port SSH server listening on port 22 by default, so attackers trying to attack your server on port 22. Changing SSH port to another port is a solution to reduce attacks. In order to change...
VNC is a fast and secure way to managing Linux systems via GUI remotely. VNC needs proper configuration to work without issue. Configure VNC on Linux systems will be difficult and confusing for beginners. Fortunately, Red Hat provides an application to create VNC configuration as a script automatically.
Over the years, XTables (IPTables, IP6Tables, ARPTables and EBTables) were using as user-space utility programs for packet filtering in Linux distributions such as Red Hat Enterprise Linux or Ubuntu. Now, Linux vendors are replacing XTables with next generation packet classification framework which called NFTables.
nftables replaces the popular {ip,ip6,arp,eb}tables. This software provides a new in-kernel packet classification framework that is based on a network-specific Virtual Machine (VM) and a new nft user-space command line tool. nftables reuses the existing Netfilter subsystems such as the existing hook infrastructure, the connection tracking system, NAT, user-space queuing and logging subsystem.
This post is about NTP Software implementations actually, but I have to write some words about NTP. NTP is an angle for financial applications, actually some of services such as banking services are very depended to clock synchronizations protocols. NTP is an ancient thing, it is more than 30 years old and even older than Windows 7 and Windows XP.
HPE Management Component Pack or HPE MCP provides agent software for use on community-supported distributions. The MCP (unlike the SPP) does not provide drivers and firmware (firmware is provided via HPSUM, and drivers are provided by the distribution vendors). The Linux Service Pack for ProLiant provides updated drivers and agent software for use on RedHat Linux and SUSE Linux Enterprise Server.
HPE Serviceguard for Linux (SGLX), a high availability(HA) and disaster recovery (DR) clustering solution, increases uptime for your critical applications by protecting them from a multitude of infrastructure and application faults across physical or virtual environments over any distance. It reduces the impact of unplanned downtime with no compromise on data integrity and performance. Furthermore, it helps achieve near zero planned downtime for maintenance.
Dynamic Software Updating (DSU) Dynamic Software Updating (DSU) is a field of research pertaining to upgrading programs while they are running. DSU is not currently widely used in industry. However, researchers have developed a wide variety of systems and techniques for implementing DSU. These systems are commonly tested on real-world programs. Current operating systems and programming languages are typically not designed with DSU in mind. As such, DSU implementations commonly either utilize existing tools, or implement specialty compilers. These compilers preserve the semantics of the original program, but instrument either the source code or object code to produce a dynamically update-able program. Researchers compare DSU-capable variants of programs to the original program to assess safety and performance overhead. Software Hot-Swapping Hot swapping can also refer to the ability to alter the running code of a program without needing to interrupt its execution. Interactive programming is a programming paradigm that makes extensive use of hot swapping, so the programming activity becomes part of the program flow itself. Only a few programming languages support hot swapping natively, including Pike, Lisp, Erlang, Smalltalk, Visual Basic 6 (Not VB.net), Java and most recently Elm and Elixir. Microsoft Visual Studio supports a kind of hot swapping called Edit and Continue, which is supported by C#, VB.NET and C/C++ when running under a debugger. Hot swapping is the central method in live coding,...
Container Linux Container Linux by Core OS (Core OS Linux) is a lightweight operating system which developed for servers and cluster under Apache License 2.0 . Initial release was October 3, 2013, 4 years ago and latest stable release is 1576.5.0 January 5, 2018. Container Linux has been developed to providing clustered infrastructure for running software on Linux containers. Container Linux has minimum software and tools, the operating system is very light and designed for hosting containers. It also provides automation solutions for application deployment, security, reliability and scalability. Overview Container Linux offers no package manager for installing and upgrading software packages, instead of installing applications, Container Linux offers Operating-system-level virtualization for deploying application on Linux containers. That way, resource partitioning between containers is performed through multiple isolated userspace instances, instead of using a hypervisor and providing full-fledged virtual machines. This approach relies on the Linux kernel’s cgroups and namespaces functionalities which together provide abilities to limit, account and isolate resource usage (CPU, memory, disk I/O, etc.) for the collections of userspace processes. Container Linux using dual boot partition mechanism for applying new security and reliability patches after reboot or kexec. Dual boot partition mechanism provides better system reliability because there is rollback point to previous state. Container Linux provides etcd, a daemon that runs across all computers in a cluster and provides a...
Starting at Red Hat Enterprise Linux Atomic Host 7.4, VMware has support this operating system as VMware Guest OS officially. Maybe, there is need to upgrade or apply patch on ESXi to support the OS.
Actually, Packet Loss occurs when one or more packet can’t reach their destination because of some issue such as link congestion, TCP can detect packet loss and send the packet again (During packet recovery process) but packet loss has impact on users, who are using streaming media application and actually all application that using unreliable protocols such as UDP.
Packet Drop is typically discarding packets on different layers after processing packets and packet drop is one of reasons of data loss in some conditions.
Shell Access via VI or VIM Why do you need to access shell via VI or VIM? A: sometimes, you have to copy result of a commands and paste those results to editor. For example, you are configuring SCSI devices as DM-Multipath devices, you have to run some commands like “multipath -l” for see “WWID” of specific device and add the “WWID” to “multipath.conf”. As simple solution, you can run another ssh session and run the command on this session, then copy and paste the result. But I think, there is another good way to do it. You can access to shell via VI or VIM editor and do your job! But how to? How to Access Shell via VI or VIM? Run VI or VIM command to open the editors and start to edit your file. For accessing to shell, you must run the below command within VI or VIM: :shell Or this command: :sh Then you will access to shell and the editor is still open. The shell is opened for your temporary, so you must have access to editor again. Press Ctrl+D or type “exit” and hit Enter for return back to the editor.
Linux tac Command tac command practically is reverse version of cat command. It means, any result in cat command will be reversed by tac command. tac is lesser known and less used command in Linux but I want to show you the command usage and some examples. Usage and Examples tac command has few options same as cat command, we’ll review some of its options at the below. Example 1 Comparison cat and tac outputs. In this example, we have a file with the below content: [root@localhost ~]# cat sample1.txt This is first line. This is second line. This is third line. This is fourth line. Now, print the file’s content by tac: [root@localhost ~]# tac sample1.txt This is fourth line. This is third line. This is second line. This is first line. Example 2 Both tac and cat commands has separator option which one of the most important options and the command is represented by the -s switch, which separates the contents of the file based on a string or a keyword from the file. [root@localhost ~]# cat sample1.txt —1— 1 2 3 —2 A B C —3– a b c [root@localhost ~]# tac –before –regex –separator=^—[0-9]+-*$ sample1.txt —3–...
