Networking FAQ 4: Fundamentals

Continue reading · 20 comments

Networking FAQ 4: Fundamentals

Continue reading · 20 comments

Networking FAQ 4: Fundamentals

Continue reading · 1 comment

Netscreen Packet Capture – Snoop

Packet Capture (cropped)

I’ve worked with Netscreens for a few years now, starting with ScreenOS version 5.x, and when troubleshooting I had always been pointed towards debug flow as the way to see what was going on. I suspect many of you have also been taught:

  • clear db
  • debug flow basic
  • (wait for packets you wanted to capture)
  • undebug all
  • get db stream (to view output)

This is definitely helpful for rule debugging but for simple packet capture is a bit over the top, which is where the snoop command comes in.

Snoop

To be clear, snoop won’t tell you anything about what decisions the firewall made about the packets, but it’s a simple way to see the actual traffic. Here’s an example of the output produced by snoop:

19944926.0: ethernet2/1(o) len=206:0010dbff2070->00005e000101/8100/0800, tag 1872
              1.4.63.82 -> 1.15.18.27/17
              vhl=45, tos=00, id=13096, frag=0000, ttl=64 tlen=188
              udp:ports 500->500, len=168
              00 00 5e 00 00 01 00 10 db a1 27 a1 81 00 07 50     ..^........p....
              08 00 45 00 00 bc 33 28 00 00 40 11 b6 18 01 04     ..E...3([email protected]
              3f 52 01 0e 12 1b 01 f4 01 f4 00  Continue reading

IPv6 Renumbering – Mission Impossible?

In one of the discussions on v6ops mailing list Matthew Petach wrote:

The probability of us figuring out how to scale the routing table to handle 40 billion prefixes is orders of magnitude more likely than solving the headaches associated with dynamic host renumbering. That ship has done gone and sailed, hit the proverbial iceberg, and is gathering barnacles at the bottom of the ocean.

Is it really that bad? Is simple renumbering in IPv6 world just another myth? It depends.

Read more ...

Fabric visibility with Arista EOS

A leaf and spine fabric is challenging to monitor. The fabric spreads traffic across all the switches and links in order to maximize bandwidth. Unlike traditional hierarchical network designs, where a small number of links can be monitored to provide visibility, a leaf and spine network has no special links or switches where running CLI commands or attaching a probe would provide visibility. Even if it were possible to attach probes, the effective bandwidth of a leaf and spine network can be as high as a Petabit/second, well beyond the capabilities of current generation monitoring tools.

The 2 minute video provides an overview of some of the performance challenges with leaf and spine fabrics and demonstrates Fabric View - a monitoring solution that leverages industry standard sFlow instrumentation in commodity data center switches to provide real-time visibility into fabric performance.

Fabric View is free to try, just register at http://www.myinmon.com/ and request an evaluation. The software requires an accurate network topology in order to characterize performance and this article will describe how to obtain the topology from a fabric of Arista Networks switches.

Arista EOS™ includes the eAPI JSON-RPC service for programmatic monitoring and control. The article Arista Continue reading

NFD9 Prep: SD-WAN

Software Defined WAN, or SD-WAN, looks to be a theme of Network Field Day 9, with presenters such as CloudGenix and VeloCloud showing us their offerings. At first glance, SD-WAN sounds pretty compelling. Who wouldn’t want to slash their WAN OpEx? How do these solutions work, and do they have legs? I’m hoping to find out.

NB: I’ve lumped CloudGenix & VeloCloud together under the heading of SD-WAN. I’m not saying that they are the same though – I don’t yet have enough information about them to fully understand the similarities and differences. I’m sure I’ll know more in a couple of weeks!

What’s SD-WAN all about?

SD-WAN is about applying concepts of SDN to WAN networks. The goals are to increase flexibility and reduce WAN costs. This can be achieved through transport independence, dynamic path management, and better config management.

Historically we used private WAN circuits – leased lines, MPLS, etc. These had great SLAs, but the monthly costs were huge. The bandwidth was low, but guaranteed. Now that many places have access to high-speed Internet tails, it’s a lot harder to justify that cost. It’s very tempting to run IPSec VPNs across Internet links instead.

Those consumer Continue reading

Device Alias on Cisco MDS

It is definitely not convenient to configure a zone or any CFS application using WWpN. 20:ab:3d:2c:4f:89:fa:ab is not very human readable and it is definitely not efficient to keep traces of the WWpN in your MDS configuration. Device-alias is a proprietary feature created by Cisco to make your life much easier. It will map an […]

Creating a Network Community for the Network’s New Operational Models

The way in which networks are configured, deployed, and managed is changing.  The network industry is in a shift from managing devices box by box via the CLI to having more centralized ways to manage and deploy devices.  While the CLI isn’t going away anytime soon, we can look at the two operational models that are gaining traction within the network community.
SDN Controllers

SDN controllers do two major things that increase operational efficiencies.  They offer a central point of management and visibility for the network team, but also offer a single point of integration for 3rd party systems – these systems could be anything from cloud management platform, monitoring or automation systems, to native business applications.  Note: even when there are controllers being used by a human, there is risk.  There is the risk of clicking the wrong button, forgetting the order of operations of which buttons needs to be clicked, etc.  This doesn’t go away.  Change control windows still have risk.

DevOps for Networking

We’ve also seen an increased amount of focus on the intersection of DevOps and networking. I’m really referring to DevOps automation tools and the network.  For Continue reading

iPexpert’s Newest “CCIE Wall of Fame” Additions 1/23/2015

Please join us in congratulating the following iPexpert client’s who have passed their CCIE lab!

This Week’s CCIE Success Stories

  • James Gusman, CCIE #46507 (Data Center)
  • Diego de Oliveira, CCIE #46343 (Wireless)
  • Mohammed Basuliman, CCIE #24626 (Collaboration)
  • Amit Singh, CCIE #19799  (Data Center)

We Want to Hear From You!

Have you passed your CCIE lab exam and used any of iPexpert’s self-study products, or attended a CCIE Bootcamp? If so, we’d like to add you to our CCIE Wall of Fame!

Confessions of technical interviewer

A technical interviewer, or technically an interviewer. I was interviewed quite a few times since I set of to join the networking crowd, 12 years ago. I also had opportunity to sit on the opposite side, and interviewed people on multiple occasions. Some of my fondest memories of working for my current employer are connected […]

Author information

Marcin Latosiewicz

Marcin Latosiewicz

Network engineer, CCIE #25784.
Technical Services Engineer at Cisco. TAC engineer.
FlexPod wizard, Vblock charmer.
@mlatosie on twitter.

The post Confessions of technical interviewer appeared first on Packet Pushers Podcast and was written by Marcin Latosiewicz.

Introducing the Plexxi Pulse Partner Summit

RN

AO

More exciting things happening at Plexxi’s offices this week. Wednesday marked a company milestone for Plexxi as we hosted the kick-off for our new partner program, the Plexxi Pulse Partner Summit.  The day-long event covered the fast-growing networking market, scale-out applications and new architectural requirements of the 3rd Platform IT era.

Attendees saw presentations from Plexxi’s executive team, including CEO Rich Napolitano; SVP of Sales and Support Tim Lieto; Founder and EVP of Products / CTO Dave Husak; and myself. We were also honored to have Cloudera’s Big Data Evangelist Amy O’Connor present to our attendees.

“The 3rd Platform Era of IT represents a huge opportunity for the channel to do something different and to change the cost of doing business for their customers.”

- Rich Napolitano, CEO of Plexxi

Participants from around the country attended including channel partners, systems integrators, technology partners and distributors.

The post Introducing the Plexxi Pulse Partner Summit appeared first on Plexxi.

Network Virtualization at VMware Partner Exchange 2015

VMware Partner Exchange (PEX) is your one-stop shop when it comes to learning about network virtualization and the technology extends VMware’s vision of the software-defined data center. At this year’s event, we are offering both an executive track and a technical track to help partners build their businesses and advance their knowledge, as you take customers on the path to Virtualizing the Network.

PEX Image

If you are a partner that is new to network virtualization, we have a program/learning path where you can send two people to PEX and to achieve their network virtualization competency by attending the 3-Day NSX Install, Configure and Manage Boot Camp prior to the start of the conference. Participants can then attend the free instructor-led VSP-NV and VTSP-NV boot camps during the conference.

If you are a partner that has already achieved your network virtualization competency, and you want advanced VMware NSX technical training, there will be eight advanced technical breakout sessions throughout the conference. The advanced technical breakout sessions cover everything from “Operational Best Practices for VMware NSX” to “NSX Security Deep Dive. Logon to PEX and build your own schedule using Schedule Builder.

Knowing the technical ins and out of VMware NSX and network Continue reading

Destination Based NAT

Here is the scenario: There is a public server on the internet that you have requested access to. The “admins” that control the server agree to allow a single public IP from your entity/company to access the server. The issue arises due to the fact that you “luckily” have more than 1 Public IP at […]

Author information

Korey Rebello

Korey Rebello

Korey is a Network Engineer and Military veteran with over 8 years of experience in the IT industry. Currently holds the following certifications; CCNP R&S, JNCIA, and CCNA Security. He is interested in advancing his network knowledge and teaching others. Currently works as a Network Engineer and is responsible for day to day operations as well as network design and implementation.
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The post Destination Based NAT appeared first on Packet Pushers Podcast and was written by Korey Rebello.

Show 222 – Introducing The OpenClos Project

Doug Hanks and Moloy Chatterjee join Packet Pushers host Ethan Banks to discuss the OpenClos project. What is OpenClos? OpenClos is open-source software written in Python that helps stand up a leaf-spine data center. Why? Standing up a DC is a fussy business – lots of cabling, IP addressing schemes, and routing protocol configuration to […]

Author information

Ethan Banks

Co-host at Packet Pushers

Ethan Banks, CCIE #20655, has been managing networks for higher ed, government, financials and high tech since 1995. Ethan co-hosts the Packet Pushers Podcast, which has seen over 3M downloads and reaches over 10K listeners. With whatever time is left, Ethan writes for fun & profit, studies for certifications, and enjoys science fiction. @ecbanks
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The post Show 222 – Introducing The OpenClos Project appeared first on Packet Pushers Podcast and was written by Ethan Banks.

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