Many people are using VPN technology today to ensure data confidentiality between remote locations. When using a site-to-site type VPN (say between a Router and a Firewall), a common complaint among end users is intermittent delay before VPN traffic is successful. This is usually due to Security Associations (SA) becoming too old requiring a ‘VPN […]
Keeping VPN SA’s Refreshed in Cisco IOS Read More »
As many of our students and clients have learned, Spanning Tree in Layer 2 Ethernets is a basic control protocol that removes logical loops from physically looped networks creating the Spanning Tree. This How To focuses on the essential configuration commands in Cisco IOS that you need to know to manage Spanning Tree. Important note:
Spanning Tree Protocol Configuration Basics in Cisco IOS Read More »
All router administrators need to take whatever security precautions they can to prevent attacks to their systems and networks. While these attacks are a continually moving target, a common attack to IP networks is called IP Spoofing. This is accomplished by sending IP packets into the network with source addresses that appear to be part
IP Spoofing Security Tip in Cisco IOS Read More »
IP mobility is software and hardware designed to provide network access as a user travels from network to network. Cisco calls this the ubiquitous connection. Cellular telephone networks already accomplish this: You can begin a cellular call in Los Angeles, CA and (in theory) you should be able to drive to New York city without
IP Mobility Primer in Cisco IOS Read More »
The following is a quick example on how to configure Cisco’s HSRP protocol. Many net admins ask about redundancy in Cisco routers and the answer is usually always the same: If your uptime has to be high, and the thought of having a failure and suffering the downtime that it will take to make the
HSRP – A Quick Configuration in Cisco IOS Read More »
Finding the right piece of information that you need from a Cisco router can often be a challenge. For example, if you use the show running-config command on a large production router, you can end up with 25 pages of text output. Locating that one piece of information you’re looking for can take a lot
Finding Configuration Details Quickly in Cisco IOS Read More »
Similar to a Windows or Linux operating systems, the Cisco IOS is rooted in Unix and has its own list of commands to manipulate files. These commands are very similar to DOS/Windows commands. Files could be your IOS router operating system executable, configuration file(s), or other type of IOS file. Knowing these file commands is
File Commands and their Usage in Cisco IOS Read More »
When learning Cisco IOS, students often ask, what happens if there is conflicting information? Cisco IOS order of operations plays an important role in how a router processes traffic and makes choices, especially if there are two possible answers. If you’re simply using the most basic features of the router, chances are good that you’ll
Cisco IOS Order of Operations for NAT and QoS Read More »
For those of you who love Wireshark and are supporting Wi-Fi Wireless networks, we would like to offer a great default profile for WiFi. Let’s make no bones about this capturing and analyzing Wi-Fi traffic is not as easy (you have to be in Monitor Mode) as just selecting this profile and clicking capture.
A Wireshark Wi-Fi WLAN Troubleshooting Configuration Profile Read More »
What is EtherChannel? EtherChannel technology is another way for you to increase the bandwidth of your core network links and provide redundancy of LAN links. It allows you to achieve greater speed by bundling Fast Ethernet or Gigabit Ethernet links, which makes a switch or router use the merged ports as a single port. This
Configuring EtherChannel on Cisco Switches Read More »
No one wants it to happen but, sooner or later, you will experience a router crash. When you do, you will want to be prepared to save that critical router memory information in order to find out why the router crashed and prevent future crashes. To do this, you need to configure your router to
Core Dump in Cisco IOS Read More »
Most users of Wireshark and T-Shark are completely unaware that neither of these programs alone actually captures packets! So wireshark people (and others), let’s dig in. Check out these great references as well: Our custom profiles repository for Wireshark Our Udemy course on Wireshark Our Udemy course on Wireless Packet capture Both programs use a
How To Use ‘dumpcap’ Natively on your Computer Read More »
For those of you who love Wireshark and are needing to analyze ARP packets, we have the profile for you. Profiles are one of the most important Wireshark capabilities. Setting up and using different profiles for different environments, protocols, and tasks is a crucial skill that we teach in our Wireshark courses. Let’s say you
A Wireshark ARP Configuration Profile Read More »
For those of you who love Wireshark and are needing to analyze DNS Queries and Responses, we have the profile for you. Profiles are one of the most important Wireshark capabilities. Setting up and using different profiles for different environments, protocols, and tasks is a crucial skill that we teach in our Wireshark courses. Let’s
A Wireshark DNS Configuration Profile Read More »
For those of you who love Wireshark and are supporting IPv4, we would like to offer a great default profile for IPv4. Profiles are one of the most important Wireshark capabilities. Setting up and using different profiles for different environments, protocols, and tasks is a crucial skill that we teach in our Wireshark courses. Let’s
A Wireshark IPv4 Configuration Profile Read More »
