Let’s say you’re trying to find a free IP on a network so you can assign one to your PC to do some work. First off, shame on you for not using proper addressing design with an IP address manager software. Second, you might use basic ping tests to properly identify alive hosts vs. dead hosts (free IP addresses). Most do. In fact, you can use nmap to do simple ping sweeps of entire subnets.
I passed 640-916 - Introducing Cisco Data Center Technologies earlier this week. I was going to publish this post on they day of or after the pass, but unfortunately I was put out of commission by the winter bug that’s going around and did not get to give this post the attention it deserved.
The first test in the CCNA Datacenter track, which is 640-911 - Introducing Cisco Data Center Networking, was a pretty straightforward test for someone with my background.
IPv6 will ruin the world! What is so terrible now will be a DESOLATE APOCALYPSE WITH IPV6!! BECAUSE…..IT JUST WILL BE - OKAY YOU GUYS???!?!?
Don’t be grumpy - be happy. NAT is not a device. It is a function. An archaic one that should and can be abandoned, and we don’t have to compromise on security to do it.
After watching the recent epic that was the comment thread on networkingnerd’s NAT66 blog post from last year, I was initially persuaded to sit and watch from afar.
I’ve had the opportunity to work with IPv6 quite a bit, and though I’ve done a few IPv6-related posts on the site, I still feel like there’s always something missing. After all, much of IPv6 is still just talk (sadly) and not enough wide-spread adoption to really put it through it’s paces.
When you’re talking about something like MTU or QoS, it’s important to think about technology implementations in an end-to-end fashion by analyzing every possible path network traffic can take - always planning for the big picture and never simply a single connection between devices. For instance, poor planning can result in confusing QoS configurations that don’t match from device to device. Depending on the platform, this can result in mismatched MTU configurations, which at worst breaks your network and at best causes elusive performance problems that can be incredibly difficult to troubleshoot.
There’s a lot of information out there about QoS and it’s an area where I’m only now starting to feel comfortable. I’ve been fortunate enough to have a decent amount of experience configuring datacenter equipment, especially in the context of a Flexpod, so I’ve been forced to know how all of these technologies play together with respect to QoS, which is very important when running sensitive applications like voice on such an infrastructure.
Yes, I invented the word “Brocatta”, and I am not ashamed.
The announcement was made today that Vyatta, a company that I’ve long used for their software routers and firewalls, has been acquired by Brocade.
The move was not a surprise to me, as Brocade has yet to define a proper SDN strategy to compete with the announcement of Cisco’s Open Network Environment and onePK. Positioning Vyatta as Brocade’s “Software Networking” business unit is a good move because now Vyatta can operate more like an R&D department with better funding than I’m sure they’ve enjoyed thus far.
I received two brand spanking new B200 M3 blade servers for a new project. These bad boys are packing 393GB of RAM and two Intel Xeon E5-2680 2.7GHz 8-core processors each.
I wanted to get these installed as soon as possible, so I could make sure the firmware was up to current (they came with 2.0(3c), which is what I’m running) and apply service profiles to them.
At the end of the initial deep hardware discovery, I received a strange error in UCSM - “Invalid Adaptor Iocard”:
This is a short one. I didn’t see a ton of information on this on the internet so I figured I’d put it forward.
I’m using a pair of Nexus 2K FEX switches (N2K-C2248TP-1GE) for 1GbE copper connectivity off of a pair of Nexus 5548UP switches.
I needed to set one of the 2K ports to access mode and place it in a VLAN. Pretty simple. After configuring one of the 2K ports through the 5K CLI though, I noticed that the port was listed as “down (inactive)”.
I had a great conversation with a coworker regarding the requirements for the In-Service Software Upgrade (ISSU) feature on Cisco switches. For this post, I’m using Nexus 5548UP switches as a distribution layer to my Cisco UCS environment, and at the core is sitting a pair of Catalyst 6500s, set up in a VSS pair.
For those unfamiliar with ISSU, it is a way for Cisco devices to upgrade their running firmware without the need for a disruptive reboot of the device, which is what has traditionally been used for upgrades to IOS, NX-OS, etc.
I strongly believe that every route/switch engineer, even highly experienced ones, should have at least a fundamental understanding of DNS architectures and best practices. More importantly, it should be understood how DNS is being used in today’s service providers and enterprises. DNS is one of those services that has been applied to many different use cases, such as a form of load balancing, or even an additional layer of security.
I am installing ESXi 5 on a Cisco UCS B440 M1 blade, and ran into some local disk issues. I used both the stock ESXi 5 image from VMware, as well as the recently released image from Cisco that contains the latest UCS drivers. Same issue on both.
The issue was that when I got to the disk selection screen on the ESXi installation, I did not see any disks:
I am happy to say that I have officially started putting things together for my CCIE R/S studies. I have been and will continue to be pulled in many different directions, but since my CCNP was completed a few months ago, and I recently passed my VCP exam, I decided that the time was now to begin the long journey ahead. I have a few other certifications in mind, and I will have to carefully weigh how they impact (or preferably do not impact) my CCIE studies, but this journey is important to me personally and professionally, so I’m pulling the trigger.
I know vXLAN has been around for a year now, but because of the reviews it got from the community immediately upon announcement, I decided to let it mature as an idea before I got involved. Here are some of my thoughts after attending a vXLAN session by Cisco at VMworld 2012.
vXLAN really just solves one problem. Most virtual infrastructures depend on L2 connectivity. vMotion is a good example of this.
I attended the VMworld 2012 session that covered the new features in vSphere 5.1 with regards to networking. Many features were rolled out to both VDS and the standard switch, and other features just had improved functionality.
First off, apparently it’s now VDS, not vDS. This announcement came hours after the announcement that VXLAN was being changed to vXLAN. Um…okay, I guess?
Anyways - The speaker pointed out at the beginning that a big change was that many of these features were being rolled out to both the standard and distributed switches.
I ran into an issue that presented itself two different ways, each at a different customer. I posted a while back about a customer that wanted to use only a single Nexus 5000, since that was all that was available. I wanted to bundle all four CNA ports on the Netapp storage array to the Netapp SAN. However, after I created this port channel and bound the virtual fibre channel (VFC) interface to it, the VFC interface would not come up.
I had the opportunity this week to ascertain the feasibility of automating the provisioning of a full Flexpod. For reference, this is considering a “vanilla” Flexpod build:
Pair of Nexus 5ks Pair of Cisco UCS Fabric Interconnects (with a few chassis) Netapp running ONTAP 7-Mode (I tested on FAS6070) Note that this also makes a few assumptions about the build.
FC via Nexus 5000, no MDS No existing vCenter integration or storage migration So - pretty much a green field Flexpod build, pretty close to the specs laid out in the design guide.
This is a (justifiable) rant. You’ve been warned.
Solarwinds Orion NPM is an okay tool, but when it comes to managing anything other than Cisco switches and routers, it’s…..meh. It takes very little effort to get devices like that monitored to the fullest extent, but when it comes to something like a storage array, it seems like you really have to make tweaks until your fingers bleed to get the minimal monitoring functionality out of it.
The SAN I’m currently working with connects a pair of Netapp FAS3270 filers running ONTAP 8.0.2 7-Mode.
If you’re running VMware ESXi in your environment in front of a Fibre Channel SAN, path selection is discovered more or less in a first-come-first-served fashion.
I got this message on my Netapp filer:
FCP Partner Path Misconfigured: Host I/O access through a non-primary and non-optimal path was detected. Since the LUNs mounted by ESXi were residing on the A-side filer, the paths going through the B-side filer would just be sent over the partner link to the A-side, which is less efficient than going directly through A.
I came across this the other day and wanted to share. For some reason, Windows by default decided to enable the “audio enhancements” feature on my new Lenovo Thinkpad w520.
This caused my microphone to essentially be unusable - I was in several webex meetings and each time everyone said I was completely garbled and not even close to being able to understand me. After a little poking around, I found this:
Matt Oswalt