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Category Archives for "Networking"

Maximum route metric on Linux

Ever wondered what is the maximum route metric value you can configure on Linux? man interface and man ip state that route metric is a number, but don’t specify its range.

# ip route add 192.168.113.0/24 via 10.0.10.1 metric 0
# ip route add 192.168.113.0/24 via 10.0.10.1 metric 4294967295
# ip route add 192.168.113.0/24 via 10.0.10.1 metric 4294967296
Error: argument "4294967296" is wrong: "metric" value is invalid

# ip route
192.168.113.0/24 via 10.0.10.1 dev eth0
192.168.113.0/24 via 10.0.10.1 dev eth0  metric 4294967295

It looks like Linux route metric is an unsigned 32-bit integer, ranging from 0 to 4294967295. As you already know a route with the lowest metric is preferred.

Getting started with TMUX

This is one of those ‘I must be living under a rock’ things.  I’m not sure how I’ve never heard of TMUX before but it’s really pretty awesome.  I initially came across it when searching for a way to share a terminal session with another user.  It does that quite well but it’s also a great terminal session manager allowing for pane, window, and session management.  Let’s take a look at a quick example to show you what I mean.

Here we have a server called ‘tmuxtest’.  The server already has TMUX on it by default but if it’s not there you can easily install it (sudo apt-get install tmux, etc).  So let’s say I want to start a new session.  The easiest way to do this is to just type ‘tmux’..

Now we’re in TMUX.  We are in what’s called a ‘session’.  The session can contain multiple panes and multiple windows.  For instance, if I wanted to create a second pane I could do by pressing ‘Ctrl-b + %’…

Notice that the screen on the right, the new one, has a green boarder around it.  That’s my active screen.  Now if I want to split this screen horizontally Continue reading

Cisco Live Berlin

I will be speaking at the CCDE Techtorial at Cisco Live in Berlin February 20-24 (just a few short weeks away)! Come by and hang out, or meet Elaine and I for lunch on Tuesday to talk about the CCDE.

The post Cisco Live Berlin appeared first on 'net work.

Cisco Live Berlin

I will be speaking at the CCDE Techtorial at Cisco Live in Berlin February 20-24 (just a few short weeks away)! Come by and hang out, or meet Elaine and I for lunch on Tuesday to talk about the CCDE.

The post Cisco Live Berlin appeared first on 'net work.

Packet loss with Fast Reroute

Packet loss with Fast Reroute Do we still lose packet with fast reroute? One of my students asked me this question. And I would like to share the answer with everyone. Before we discuss whether or not we lose packet with fast reroute mechanisms, let’s remember what fast reroute is. It is pertinent to know […]

The post Packet loss with Fast Reroute appeared first on Cisco Network Design and Architecture | CCDE Bootcamp | orhanergun.net.

BrandPost: How to Beat the Wired Network Bottleneck and Wring More Business Value from your WLAN

If you’re looking at deploying 802.11ac Wi-Fi access point (AP) technology, as most companies have already, you may want to consider upgrading the speed of your wired connection between your APs and your wiring-closet Ethernet switch to avoid the kind of network saturation that puts a damper on worker productivity.  The 802.11ac Wi-Fi standard now accounts for 67.1% of dependent wireless AP shipments and more than 80% of revenue, “setting the stage for near obsolescence of the 802.11n standard by 2018 in the mainstream enterprise segment,” according to the research firm IDC.To read this article in full or to leave a comment, please click here

Microsoft employees say monitoring disturbing content traumatized them

There is a very dark underbelly to the web that is not for the weak of stomach. You may be thinking of 4chan, but that place is just the starting point. Unfortunately, it falls to some people to monitor this garbage for law enforcement, and in the case of two Microsoft employees, it drove them over the edge. In a lawsuit filed against Microsoft, Henry Soto and Greg Blauert claim they were forced daily for months to view some of the most disturbing photos and videos you can find on the internet and that Microsoft did nothing as the constant viewing took its toll on them. They now claim to suffer Post-Traumatic Stress Disorder (PTSD). The two were part of Microsoft’s Online Safety Team, a group formed to investigate content being stored on Microsoft sites, like OneDrive, that should be taken down or reported to police. To read this article in full or to leave a comment, please click here

Google Cloud Key Management Service could help more enterprises encrypt data

Attackers are increasingly able to penetrate perimeter defenses, compromise accounts and mine data without targets even being aware of the attack, as the Democratic National Committee breach proved. Encrypting data is the best defense.Strong encryption of complex data structures requires a Key Management System (KMS). But implementing a KMS can be challenging, especially for enterprises below the security poverty line that don’t have the budget to hire a multidisciplinary security team. Google may have a solution with its Cloud Key Management Service (CKMS) now in beta in select countries.  To read this article in full or to leave a comment, please click here

Google Cloud Key Management Service could help more enterprises encrypt data

Attackers are increasingly able to penetrate perimeter defenses, compromise accounts and mine data without targets even being aware of the attack, as the Democratic National Committee breach proved. Encrypting data is the best defense.Strong encryption of complex data structures requires a Key Management System (KMS). But implementing a KMS can be challenging, especially for enterprises below the security poverty line that don’t have the budget to hire a multidisciplinary security team. Google may have a solution with its Cloud Key Management Service (CKMS) now in beta in select countries.  To read this article in full or to leave a comment, please click here

Worth Reading: Tier 1 carrier performance report

As Noction continues to intelligently optimize routing for more and more networks around the world, we find ourselves in the unique position of having great insights into the general Internet performance as well as the performance of specific Internet carriers, when analyzing data collected by IRP Lite instances. Around 200 million successful probes performed by IRP instances over the previous weeks offered us plenty of data for analysis. The current report card covers the performance of major providers within the continental United States. —Noction

The post Worth Reading: Tier 1 carrier performance report appeared first on 'net work.

Worth Reading: Tier 1 carrier performance report

As Noction continues to intelligently optimize routing for more and more networks around the world, we find ourselves in the unique position of having great insights into the general Internet performance as well as the performance of specific Internet carriers, when analyzing data collected by IRP Lite instances. Around 200 million successful probes performed by IRP instances over the previous weeks offered us plenty of data for analysis. The current report card covers the performance of major providers within the continental United States. —Noction

The post Worth Reading: Tier 1 carrier performance report appeared first on 'net work.

44% off YETI Rambler 64oz Stainless Steel Vacuum Insulated Bottle with Cap – Deal Alert

With double-wall vacuum insulation, these over-engineered drink holders keep your favorite beverage as cold -- or hot -- as science allows. Over-the-nose wide mouth, anti-condensation, puncture and rust-resistant, no-leak cap, and a giant 64-oz capacity that can fit everything from a growler of beer to multiple bowls of soup. The Yeti Rambler is currently listed for the very low price of $49.99, a good deal considering its $89.99 list price. See the high-end, over-engineered Yeti bottle now on Amazon. To read this article in full or to leave a comment, please click here

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