In 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. 

During designing and implementation of wireless network you will come across on Layer 2 and 3 roaming. Both of them improve scalability of the wireless network  and simplify end user life, but work differently.

When we think AAA server we think about Radius and TACACS+ servers. The servers that are responsible for authentication, authorization and accounting. What is, what we may get of AAA server and how to use its, let’s check it on real examples.

Since routers and multilayer switches use Cisco Express Forwarding feature, the true that switches are much more faster than routers is not a true anymore. Nowadays routers can make decision with the wirespeed likely switches with ASICS. What is CEF, how works and how helps out the routers in packets routing ?

In simple network that doesn’t consists of a large numbers of routers, doesn’t relay on more than one routing protocol or doesn’t use BGP you may never come across Route Maps, but if one of above conditions is fullfiled then for sure sooner or later you will have to consider using route maps. What are, when and where use them and how do they work ? Let’s check out.

Usually if we mention about Public Key Infrastructure we think about external Certificate Authority like Verisign or GoDaddy. It turns out, there is a SCEP protocol that enables us running our own CA in Cisco environment and that certificates we may use during ISAKMP IKEv1 or IKv2 authentication.

In the course of time the CLI tools that have appeared in particular versions of Linux distributions evolved significiantly. From ifconfig through ip to the nmcli and many other like ss, isof etc. Let’s have a look at Linux from  the perspective of networking, its configuration, management and troubleshooting.

Crone and NTP (network time protocol) services are to some extent linked with each other despite they do completely different things. Crone is responsible for automating of processes, NTP for keeping time on our server up to date, but correct work of Crone is dependant on correct work of NTP.

You may be familiar very well with BGP protocol but probably until you don’t start use MPLS L3 VPN or IPv6 you will not have awareness that the other kind of BGP addresses exist. For carrying the other BGP addresses responsible is Multi Protocol BGP,  that we  break down right now.

Vmware vSphere offers two amazing solutions in regard to ensuring high availability. One of them is called High Availability and the second one Fault Tolerance feature. Both of them complement each other providing uninterrupted working of the virtual machines in cluster.

Zone Based Firewall in IOS, combines 2 concepts: Modular Policy Framework and well-known Zones from ASA firewalls. ZBF solution is more secure than ACLs, easier to implement and to troubleshoot. Rely on statefull filtering what is also well-known from ASA firewalls. Despite this, is not fresh solution, but still works out very well.

Every network has to be measurable. It means that you have a view on processes, accidents that take place in the network. You have to be aware what happens and why, in the network that you administer. There is a couple of protocols that helps us to deal with this issue.