Conversion between particular systems seems to be not necessary nowadays, what may be  pernicious. Besides, for any IT guy it’s a shame don’t know how to make simple math that sometimes may be really helpful.

Rsyslog and journald daemons gives you an opportunity to control what happens in the system. You may trace users and their interaction with other daemons. They increase  security, cause based on the logs you can make decisions regarding users that unusuall  behaviour you’ve noticed. Also, if there is a problem with system stability or system is not running…

yum managersmall121Even very well designed operating system as Red Hat without software is worth not too much. In Red Hat and CentOS we use the same tools to get the programs and keep them up to date. Let’s have a look on RPM and YUM package manager.

vpc-supported-topologiessmallSpanning Tree Protocol is not a good idea especially if we take into consideration data center. Wasting of bandwith by blocking links in environement which demands the highest throughput, is not desirable. Virtual Port Channel feature sorts it out in simple and clever way.

Security-Researchers-Able-to-Crack-1024-bit-RSA-EncryptionThere are 3 ways regarding authentication within IKEv1 and IKEv2. So we have,  pre shared keys, rsa-enc and rsa-sign. Each of them provides different level of security. In this article we will focus on RSA based methods and we lab them out.

Nowadays, when access layer switches have 1GB ports, increase the upstream link to the distribution layer is necessary. Let’s have a look on etherchannel feature, the way that we may achieve that and how to configure its on layer 2 and 3.

linux-raid-featuredIf we run any file server or backup server that require high availability and redundancy the first thing that we should think about is RAID array, especially in Linux environment, where creating and configuration is easy to make. Let’s configure simple RAID 1 mirroring with 2 hard disks from a scratch.

centos-runtimelevelIn linux environment if you are going to move between graphical and text modes, knowing runlevels or boot targets is fundamental. Also is important how to manipulate and modify particular targets and services that are being run with them.

Spanning Tree Protocol and its variations is responsible for elimination loops and ensuring efficiency at layer 2 . Despite was invented 30 years ago and nowadays very often between Access and Distribution layers routing is utilized, it is still good to know how works and what is responsible for. 

FlexVPN is being called “one to rule them all” and there is no exaggeration in this statement. VPN that allows you for site to site connection with the remained VPNs like VTI, DMVPN and by the way for remote access as well. Let’s break FlexVPN down  based on site to site configuration.