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Networking 101 Video - Switch Latency

Jimmy Ray Purser from TechWise TV  provides a pretty good review of how switch performance is measured. Topics reviewed include cut-through switch latency, store and forward switch latency, FIFO, LIFO, and LILO. Check it out if you've always wanted to know how to measure the speed of a switch.

Here's a direct link if the video embed code doesn't load in your browser:

Forced Memory Upgrade on a Cisco ASA 5505

ASA 5505

About a week ago, my home Internet connection started to show signs of degradation. Emails weren't being sent, websites partially loaded, and in general things were "slow". If this was an enterprise network and I was a non-technical user, I would have promptly opened a help desk ticket with the title of "the Internet is Down!" or "The network is slooow". Since this isn't exactly an enterprise network (cobbled together hodge-podge is a more accurate description) I knew it was up to me to make things right. So, I quickly put on my troubleshooting hat and went to work.

After a bit of looking (and reboots), I found a solid amber status light on my ASA5505. This was the last place I looked because the thing has been as solid as a brick for the past 4 years. I tried to connect to it via SSH and Console, neither worked. Rebooting it did nothing. 

Wireshark updated to version 1.6.6

A new version of wireshark has been released. A full list of features and updates are in the official announcement.

For reference here is the updated protocol support and new file capture support:

Updated Protocol Support

   PacketBB, PGM, Radiotap, SSL, TCP, UDP, USB, WSP

  New and Updated Capture File Support

   Endace ERF, Pcap-NG, Tektronix K12

You can download the latest version here:

Cisco Acquires Lightwire


Cisco announced yesterday their acquisition of Lightwire, Inc., a company that manufactures network transceivers. Since Cisco already offers their own brand of optical transceivers, this deal will most likely give them a cost cutting edge for creating high speed optics.

According to the press release, the deal cost a cool $271 million. 

The intellectual property and manufacturing processes gained in this deal will likely help Cisco make better optics. However, the retail price points will likely remain unchanged, so Cisco should expect to see higher margins on future high speed optical sales. If you've ever bought a fully loaded Nexus 7010, the optics are a significant percentage of the price.

CCNA Service Provider

I received an email announcement today regarding Cisco's new CCNA Service Provider certification. This is in addition to the already available CCNA Service Provider Ops certification.

There are two exams that need to be passed in order to achieve this certification, the SPNGN1 and SPNGN2.There are no prerequisites.

You can check out the full list of exam topics on each exam page, but needless to say the list is extensive. By the end of the certification, you should have a good introductory understanding of the following:

Cisco Security Advisory - NX-OS Denial of Service Vulnerability

Cisco recently announced a vulnerability in their NX-OS for the 1000v, 5000, and 7000 platforms. If you are running Nexus in your network, be sure to check this one out because it could cause an outage.

In order for this vulnerability to be exploited (or randomly occur), a malformed IP packet has to enter into the Nexus and one of several conditions can trigger the problem. The advisory notes provide a few examples of how to trigger the problem including the following: a malformed packet with a TTL value of 1 that would cause the Nexus to send an ICMP time exceeded error message. The process of generating the ICMP message could trigger the bug.

What's Vulnerable and How do I fix it?

Here's a list of the versions with the vulnerability and the version with the fix, per platform:

Apple unveils iPad 3


Apple announced their latest revision of the popular iPad. Along with it comes iOS version 5.1 and a host of new features including:

  • Retina display (over 3.1 million pixels, 2048x1536 resolution) 
  • New 5mp camera that captures 1080p video
  • 4G LTE
  • A5X chip to support the new display
  • Siri, sort of. You can dictate instead of type, which is pretty handy. Don't have the full assistant yet.

The new device is officially shipping March 16th in a long list of countries, many more to follow not too long after. If you just can't wait to hand your money over for one of these shiny new toys, you can pre-order your device right now. Just be ready to fork over at least $499 US.

Configuring NTP on a Linux client

I had to setup a Linux client this weekend and wanted NTP to sync the time with the rest of the systems on the network. Much to my surprise, ntpd wasn't installed on the box by default so I had to get it setup. Figured I'd share the steps I followed in a blog post to share the knowledge. Here it is...

To install ntpd, you can do it a couple different ways (such as downloading it from and installing it manually) or you can use your favorite installer (I use apt-get):

sudo apt-get install ntp

Then you need to edit the /etc/ntp.conf file to point to the server you want to grab the time from. Since the installation started the process for me, I wanted to stop it before editing the conf file:

service ntp stop

Also, you might need to chmod the file first to allow writing to the file:

Navigating the IOS command line

I decided to put together a quick blog post on some handy IOS file management commands. I'll likely add to this again in the future to make it more complete, but I wanted to get something started, so here it is..

dir - Get a directory listing of whatever path your are in. 

Using Windows Server 2008 as a RADIUS Server for a Cisco ASA

The title says it all. I just forwarded this link to a guy who knew VERY little about Cisco and he was able to pull off LDAP authentication for an SSLVPN by following these well-documented steps:

Handling Visio Connectors

If you've just gotten into Viso to create network diagrams, chances are you'll be cursing Microsoft for the "connector" feature pretty quickly. Thankfully Jeremy Stretch (PacketLife) has put together a quick and simple explanation for handling this pain point:

Google+ Hangout, This Friday

UPDATE: This will be from 9:00am - 9:30am PST on Friday 2/10/12.

This should be fun - CBTNuggets is testing the new Google+ Hangout feature, which is live video/audio conferencing with a group of people. This Friday from 9:00am - 9:30am PST, I'll be doing a live Google+ Hangout session...answering questions, throwing out thoughts, and well...just hanging out. Here's the link:

Apparently, a "Hangout with Us" or something similar will appear come Friday. I think it has a 'people limit', so you may have to try a couple times to get in. 

See you then!

Prolific USB to Serial on OS X Lion

Kudos to this superstar who easily got my USB-to-Serial adapter going on OS X Lion! This now makes two guys named Martijn I admire from the Netherlands...must be a trend.

I Love Tools Like This: HFS

Why do I like TFTPD32? Because it's so freakin' simple! When you're in a data center and need a quick TFTP server...there it is.

...who knew they had one for HTTP? There it is: HFS - A 600KB "insta-web server" for Windows.

Update: A few malware detection utilities flag this as malware simply because it's a .exe file named HFS. It's completely safe...I've been using it for at least 32 minutes and nothing bad has happened...

Firefox 10 is out

Mozilla drop-shipped the 10th version of their browser on the world today. New stuff in Firefox 10 includes bug fixes, developer tools, and some other neat stuff. 

You can get the latest version by giving in to the nag box that pops up in previous versions or by clicking here:

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Dr. Radut