An EIGRP Scaling Puzzle
This last week I received an email from a friend asking about scaling. The situation is this: a particular company has well over 100 EIGRP routers on a single L2 service from a provider. Will this scale? What’s more interesting than simply asking about scale, though, is to ask the “why” question — no matter […]
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Cisco Targets SMBs In WLAN War With HP/Aruba
Cisco's new WLAN product, Mobility Express, targets customers who want simple deployment, and gives Cisco a weapon against HP/Aruba.
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DHCP Details You Didn’t Know
If you’ve been a networking engineer (or a sysadmin) for a few years, you must be pretty familiar with DHCP and might think you know everything there is to know about this venerable protocol. So did I… until I read the article by Chris Marget in which he answers two interesting questions:
- How does the DHCP server (or relay) send DHCP offer to the client that doesn’t have an IP address (and doesn’t respond to ARP)?
- How does the DHCP client receive the DHCP responses if it doesn’t have an IP address?
Risky Business #384 — Mark Dowd talks AirDrop pwnage, XCode iOS scandal
We've got a great show for you this week. Mark Dowd drops by to talk about the recent spate of Trojaned iOS apps that made it into Apple's China App Store. We also talk to him about his awesome AirDrop bug. How did it work?
This week's sponsor segment is actually a real cracker. Context IS consultant David Klein tells us how he owned an entire cloud platform by enumerating some shitty 90s-style bugs in some third party libraries they were using. It's comedy gold. This cloud platform that uses security at a selling point. It's bad.
Networking Field Day 10 – Arista
I finally had the chance to finish watching all of the Arista videos from Networking Field Day 10. They did quite a few presentations and if you haven’t watched them yet I would recommend you do…
While the bulk of the videos talked about Arista platforms or features, Ken Duda’s presentation (EOS Evolution and Quality) really struck a chord with me. Early in the presentation Ken summarizes the problem by saying “when the network ain’t working, ain’t nothing working”. The software powering your network just has to work and it has to work consistently. Ken then goes into where he thinks quality should come from breaking it into 3 pieces.
Culture – It’s obvious from Ken’s talk that Arista legitimately cares about software quality. While I don’t think this is unique to Arista, I think it’s something they’ve fully embraced because they can. Arista was born out of the commodity network era. When you are working with commodity chips, the real differentiator becomes software. This puts them at a unique position compared to other traditional vendors who Continue reading
Cisco in China: If You Can’t Beat ‘Em, Join ‘Em
Having struggled in China since Snowden, Cisco is taking a new tack.
Using Docker Machine with OpenStack
In this post, I’m going to show you how to use Docker Machine with OpenStack. This is something I’ve been interested in testing for a while, and now that I finally have my test lab back up and running, I was able to spend some time on this. I’ll spend some time later in the post covering my reasons for wanting to look at this, but I’ll start with the technical content of how it works.
I tested this setup with the following components:
- The client system was running OS X 10.9.5 with the Docker 1.8.2 client binary and Docker Machine 0.4.1.
- The OpenStack cloud was running the Juno release on Ubuntu 14.04 LTS, KVM hypervisors, and VMware NSX for networking.
There are (at least) two approaches to using Docker Machine and OpenStack together:
- You can use Docker Machine’s
genericdriver to consume already-provisioned OpenStack instances. This is, in large part, very similar to what I covered here, but I’ll cover it in this post just for the sake of completeness. - You can use Docker Machine’s
openstackdriver to automatically provision and configure new instances on an OpenStack cloud. This is the Continue reading
A Quick Reference to Adding New Storage with LVM
This post walks through the process of adding storage capacity to a Linux server using LVM. There’s nothing new, revolutionary, or cutting-edge about this post—honestly, it’s really more for my own reference than anything else. Adding logical volumes is something that I do so infrequently that it’s hard to remember all the commands, so I’m recording them here for when I need them next time.
First, list the physical disks in the system (all commands should be prefaced with sudo or run as a user with the appropriate permissions):
fdisk -l
This will help you identify which (new) disk needs to be added. In my examples, I’ll use /dev/sdb.
Start partitioning the new disk (replace /dev/sdb with the appropriate values for your system):
fdisk /dev/sdb
I’m assuming that this isn’t a boot drive and that whatever logical volumes you create will take up the entire disk. Once you get into fdisk, follow these steps:
- Enter
nto create a new partition. - Enter
pto make this a primary partition. - Enter
1to make this the first partition on the disk. - Press enter twice to accept default start and end cylinders (unless you know you need to change them).
- Enter
Continue reading
Opengear Saves the Day from 35K Feet
On Tuesday, I was boarding a flight heading to the west coast and realized I had 3 switches powered down in the colo that I needed for a presentation and demo on Wednesday. Not a good feeling.
We have an IP enabled PDU that I usually connect to with no issues from the office and home office since we also have an SD-WAN deployed using Viptela. The only issue — there is not a way to VPN into the colo (yes, that’s my fault).
As it turns out, I had exposed the Opengear console server, that we used for all out of band access, to the Internet a few months prior. On a flight that I was only planning to do offline work, I was forced to purchase Wifi…from there, the fix was pretty simple.
I SSH’d into the Opengear console server, got access to the Juniper SRX perimeter FW, and then added a temporary NAT configuration that exposed the PDU to the Internet. I was able to now access the PDU directly from 35K feet in the air, get the devices powered up, and have some peace that they could be used in the demo. Sure, I could have Continue reading
ONF Debuts Northbound Interfaces for Intent-Based Networking
The intent-based Boulder & Aspen projects are designed to open up networking.
Increased Security Spending: Good Money After Bad?
A couple of recent analyst reports tout significant growth in the information security market. But More security spending on products doesn’t necessarily mean better outcomes for customers.
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Tower 2.3 Has Arrived
We’re happy to announce the release of Ansible Tower 2.3, our console and service that brings control, security, and delegation to your Ansible deployments.
Historically Tower has been installed with a simple setup playbook that you run with the Ansible you already have to download and install Tower. But not everyone has the luxury of access to the internet at all times.
Starting with Tower 2.3, we now offer a bundled installer for Red Hat Enterprise Linux and CentOS systems. This all-in-one installer contains everything you need to get Tower started in one bundle, including bootstrapping of Ansible for you as needed. All you need is a Red Hat or CentOS machine with access to the vendor OS repositories - no other external access required. The playbook installer is still available as well, and Tower is also still available via Vagrant image or AMI if you’d prefer to try it via that method.
As usual, this release of Tower includes a variety of bug fixes as well, including performance improvements around listing jobs and job templates.
For more information on Tower 2.3, check the release notes at: http://docs.ansible.com/ansible-tower/latest/html/installandreference/release_notes.html
To try Ansible Tower 2.3 Continue reading