Someone recently sent me this question:
Is it possible to prepend one IP address from a public IPv4 segment?
I don’t want to know what crazy stunt this engineer was forced to pull off, but just in case you land in a similar quandary here’s how you shoelace yourself out of it.
Read more ...Today, We wish and hope all of our friends and students have a very Happy Thanksgiving!
If you haven’t heard of CoreOS it’s pretty much a minimal Linux distro designed and optimized to run docker. On top of that, it has some pretty cool services pre-installed that make clustering CoreOS pretty slick. Before we go that far, let’s start with a simple system installation and get one CoreOS host online. In future posts, we’ll bring up more hosts and talk about clustering.
The easiest way to install CoreOS is to use the ‘coreos-install’ script which essentially downloads the image and copies it bit for bit onto the disk of your choosing. The only real requirement here is that you can’t install to a disk you’re currently booted off of. To make this simple, I used a ArchLinux lightweight bootable Linux distro. So let’s download that ISO and get started…
Note: I use a mix of CoreOS VMs and physical servers in my lab. In this walkthrough I’ll be doing the install on a VM to make screenshots easier. The only real difference between the install on either side was how I booted the ArchLinux LiveCD. On the virtual side I just mounted the ISO and booted Continue reading
A third of my readers are celebrating Thanksgiving today, and I’d like to use the opportunity to say what I always wanted to say but somehow never got to it. Let’s make it short: Thank you! Without you, there would be no ipSpace.net.
Read more ...[player] Orhan Ergun and Jeff Doyle talks about IPv6 design and deployment considerations in the Enterprise networks. They strongly advice you to consider IPv6 deployment in your network. Why IPv6 in the Enterprise , what are the real business drivers for the IPv6 ? Growth of IPv6 in the Enterprise Networks Jeff Doyle’s advices to […]
The post IPv6 in the Enterprise by Jeff Doyle and Orhan Ergun appeared first on Packet Pushers.
Orhan Ergun and Jeff Doyle talks about IPv6 design and deployment considerations in the Enterprise networks. They strongly advice you to consider IPv6 deployment in your network. Why IPv6 in the Enterprise , what are the real business drivers for the IPv6 ? Growth of IPv6 in the Enterprise Networks Jeff Doyle’s advices to Service […]
The post IPv6 in the Enterprise by Jeff Doyle and Orhan Ergun appeared first on Packet Pushers Podcast and was written by Orhan Ergun.
A different kind of war story this time: Unix security blunders. Old-school Unix-types will mutter about how much more secure Unix systems are than Windows, but that glosses over a lot. In a former life I worked as an HP-UX sysadmin, and I saw some shocking default configurations. I liked HP-UX – so much better laid out than Solaris – but it was very insecure by default. Here’s a few things I’ve come across:
We’d lost the root password for a test HP-UX server. We had user access, but not root. The server was located in a different DC, and we didn’t really feel like going and plugging in a console cable to reset the root password. So we started looking around at how we might get access. After a while I found these two things:
And now for the kicker:
hpux lhill$ ls -ld / drwxrwxrwx 30 root wheel 1020 1 Nov 13:57 /
Put those together, and you can see it’s easy to gain root. All we needed to do was create /.rhosts, and add whatever Continue reading
When running services on nodes in a CORE Network Emulator scenario, we may wish to customize the services configurations.
Some reasons why a user may customize CORE services are:
To show how to customize CORE Services, we will work through a detailed tutorial that shows how to customize the IPForward service. We will work through the same steps required to customize any other CORE Service.
The IPForward CORE Service provides a script that runs when the node starts in a simulation scenario. The script sets the IP Forwarding kernel parameters so that the node will forward packets from one port to another, according to the routing table on the node. The IPForward script is a default service on the Router node type.
The default IPForward CORE service has limited functionality: it can start IP forwarding on a Continue reading
These are two standards for single mode fibre optic cabling from a total of five types of fibre that are generically used today known of “OF types” (OM1, OM2, OM3 for multimode and OS1,OS2 for single mode.) OS1 is for indoor use i.e. Campus, Data Centre. Cabling is is tight buffered (i.e. manufactured into solid […]
The post Tech Notes: Difference Between OS1 and OS2 Fibre Optic Cable appeared first on EtherealMind.
Who would you trust more to fix your car, a licensed mechanic or a guy who once saw someone do an oil change? The choice should be simple. But surprisingly, the debate over trusting an expert versus someone who claims to be an expert happens every day across all industries, so it shouldn’t be shocking that the debate rages in the cloud, too.
Cloud computing enables people and companies to access applications from any computer. But the cloud has created a new group of cloud posers -- inexperienced software developers who make bold (and often untrue) claims about the performance of the cloud-based applications they manage. While on the surface they may seem like a good choice to support your business, once you start asking smart questions, a cloud poser’s true colors (and lack of expertise) will quickly be revealed.
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Service Level Agreements (SLA) serve as a roadmap and a warranty for cloud services offerings. All cloud providers offer standard, one-size-fits-all SLAs that cover availably, performance, security, disaster recovery, response times, compliance and termination. This may be adequate for pure cloud applications, however standard SLAs fall short when it comes to hybrid cloud deployments.
There is nothing standard about hybrid deployments. Each one is different and inherently includes a higher level of involvement from IT. SLAs need to establish clear guidelines of engagement for both the enterprise and service provider. Unfortunately, not all cloud service providers are open or equipped to customize SLAs.
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It was a dark stormy autumn night and three networking engineers had nothing better to do than ponder the heavy topics of transactional consistency in a distributed SDN environment in Episode 16 of Software Gone Wild podcast.
Here are a few of the topics that crossed our minds:
Read more ...Woke up to a very nice email today.
I have been selected as a Cisco Champion for 2015! – Now i get to see what all the fuzz is about and hopefully be able to contribute something.
I always enjoy reading the IPspace blog and as Ivan has stated about our blog, I don’t always agree with his opinion, but they are informative and cover just about everything networking. So this may come as a surprise, but in response to his “Do we have too many knobs” post from about a week ago I have one simple response: “Amen”.
Networking is unnecessarily complicated. We have written several blogs on this topic and related items. I used to run the sustaining organization for all data products at my previous company and when you do the analysis of the customer reported issues that come in to the support organization, you find that a very large percentage stem from configuration mistakes.
Many of those mistakes are not typos. We like to refer to fat fingered configurations often as a reason to move to a more automated configuration and provisioning environment, but most of the configuration mistakes that are made are simply because we have made it so difficult to configure these devices. Type something in the wrong order and it may not work right or behave slightly differently. Simple checks across configurations that could avoid many problems are Continue reading
We're sitting out a few days from Thanksgiving in the U.S., and it's time once again to give thanks to people in our free software community.
On a related note, a while back James Martin and I were having a conversation about what the collective noun for Ansible-using-people was. We came up with "Ansiblings" - somewhat because it reminds me of Starcraft zerglings, because we are numerous, aggressive, and get things done fast-- but that's not so much why. More so, because Ansible users are kind of a family. This year, our way of giving thanks to our family won't be with a tryptofan-soaked turkey (Wikipedia seems to say that's a myth but what do they know?), but rather with another great release of Ansible.
YES -- Ansible 1.8 is now available on PyPi and our official Ubuntu PPA, and will soon be available via other packaging mirrors. And at this point, Ansible's reached an amazing 919 contributors on GitHub, with over 8400stars and 2600 forks, and you can find a large list of dedicated meetup groups all over too.
One of the most notable features in Ansible 1.8 has been the long Continue reading
