This post is a companion to the previous GNS3 with Microsoft Azure post. For many of us, an asymmetrical Internet connection usually equates to a much slower upload than download speed. Specifically, in our case, this results in a time-consuming process of uploading GNS3 image files to our remote gns3server VM instance. What if we need to recreate the disk attached to our gns3server VM instance? Modify the type (i.e., HDD to SSD) or decrease the size of the disk, which again would require us to recreate the disk? What if we need to spin up multiple gns3server VM instances for training purposes? Each situation may require a good amount of unnecessary (re)uploading. ...

Microsoft Azure is one of the big three public cloud computing providers for services such as virtual machines (VMs), containers, server-less computing, and machine learning. Azure is a large platform, but we’re focused solely on the Infrastructure as a Service (IaaS) resources in this guide. The GNS3 architecture is comprised of three primary components: User Interface (UI), Controller, and the (Compute) Server. The Server is the component that puts a strain on computer hardware resources. The more routers, switches, firewalls, and servers we add to our GNS3 topologies, the more CPU, RAM, and data storage we require. We usually come to a point where the hardware requirements of our GNS3 labs may exceed what our laptops and desktops can deliver. ...

Steps Identify or create the VMnet for capturing network traffic. If you’re using the standard version of VMware Fusion, this will be Share with my Mac (vmnet8), Private to my Mac (vmnet1), or Bridged (vmnet0). VMware Fusion Pro includes the feature to create additional custom VMnets with the virtual network editor. Note that a host adapter is not required to capture traffic on the VMnet. Create a named pipe (FIFO) file for the VMnet. I prefer to create a separate file for each VMnet. It provides the flexibility to capture and display on multiple VMnets simultaneously. Run the following command in Terminal: ...

Wireshark is the world’s most popular network analyzer. A network protocol analyzer is usually required to get the deepest visibility in determining network issues. Grabbing the newest Wireshark release for Windows and Mac OS X is easy enough. You just direct your web browser to the Wireshark site to grab it. Things can be a little trickier if using Linux. The Wireshark package listed with most Linux distribution repositories is usually a version or two behind the current stable release. Even if the repositories have the latest stable release, what do you do if you want to try out the bleeding edge features of the latest development release? You may have no other choice except to do a source-based installation. This post will show you how to do just that. ...

Cisco Router and Security Device Manager (SDM) is a Web-based device-management tool that enables you to deploy and manage the services on a Cisco IOS router. Even if you decide to do your initial configuration with the CLI, the Monitoring mode of SDM is a great way to display a graphical real-time pulse of the state of your router. The SDM application can run either as an application installed on your Windows PC or from the router’s flash thru the web browser. This post will show you how to run the SDM application on Mac OS X. This should go without saying, but don’t expect official support from Cisco regarding this configuration. ...

I recently had an issue where I wanted to play a movie on one of my portable devices, but the file’s audio stream is encoded in the AC3 (Dolby Digital) format. But of course, the device doesn’t support AC3, so I need to convert it to a compatible format. Handbrake is my go-to tool for media file conversion, but it no longer supports output to XviD – specifically the AVI container. I could convert the whole file, but I was looking for a way to transcode the audio but leave the XviD video stream intact. This method is ideal because transcoding video is the most time-consuming operation of the media file conversion process. I researched further with the knowledge that Handbrake leverages FFmpeg. ...

I created a PowerShell advanced function that emulates the uptime command for Unix-like operating systems. The uptime command displays the current time, the length of time the system has been up, the number of users, and the load average of the system over the last 1, 5, and 15 minutes. uptime output: 21:33 up 7 days, 11:10, 2 users, load averages: 0.05 0.08 0.08 My function returns a custom PowerShell object, so we have the option to pass it to the pipeline for further processing and/or formatting. ...

Lately, I’ve been implementing a solution to make SSH connections more secure and manageable (i.e., getting away from password authentication). A couple of benefits public-key authentication has over the default password authentication is: Memorize only the passphrase of your private key rather than possibly dozens of username/password combinations for remote hosts. A password sent across the network, even protected by an SSH secure channel, can be captured when it arrives on the remote host if that host has been compromised. Steps Generate the key pair. RSA authentication will need a passphrase to encrypt the private key. It’s highly recommended to create a strong passphrase for the private key. A strong passphrase is at least 10 - 15 characters long and not a grammatical sentence. The following command creates a 4096-bit RSA key pair and also prompts you for a passphrase: ...

I recently had to configure Inter-VLAN routing at a client’s site. I don’t have to perform this task on a regular basis, so I figured I would make a post of a sample implementation for future reference. Ingredients used for this post: Cisco 2811 Router Cisco Catalyst 3560 Cisco Catalyst 2950 Steps Configure the Corp router. enable conf t int fa 0/1 description Link_to_L3SW ip address 172.17.17.9 255.255.255.252 no shut end copy run start Configure the Cisco Catalyst 3560 switch. enable conf t vtp mode server vtp domain test vtp password test vlan 10 name Marketing exit vlan 20 name IT exit int gi 0/1 switchport trunk encapsulation dot1q switchport mode trunk switchport nonegotiate exit ip routing int vlan 1 ip address 10.100.1.1 255.255.255.0 no shut exit int vlan 10 ip address 10.100.10.1 255.255.255.0 no shut exit int vlan 20 ip address 10.100.20.1 255.255.255.0 no shut exit int fa 0/24 no switchport ip address 172.17.17.10 255.255.255.252 no shut exit ip route 0 0 172.17.17.9 end copy run start Configure the Cisco Catalyst 2950 switch. enable conf t vtp mode client vtp domain test vtp password test int fa 0/1 - 4 switchport mode access switchport access vlan 10 exit int fa 0/5 - 8 switchport mode access switchport access vlan 20 exit int gi 0/1 switchport trunk encapsulation dot1q switchport mode trunk switchport mode nonegotiate exit int vlan 1 ip address 10.100.1.2 255.255.255.0 no shut exit ip default-gateway 10.100.1.1 end copy run start

I routinely google this task whenever I have to install or upgrade the VMware Tools on a Linux VM guest. I figure I would make a post for future reference. Ingredients used for this post: VMware ESX Server 4.0 Ubuntu Server 9.10 Steps Use the vSphere Client to connect to a vCenter Server or directly to an ESX host. Right-click the virtual machine and select Open Console. Log into Ubuntu with an administrative account. ...