How does the internet work - We know what is networking
Now that my topology in GNS3 is exactly as in INE Workbook 1 I can share it with you if you don’t want to do all the basic configurations and connections by yourself. After spending too much money on different rack rentals in the past few months I decided that I will definitely need to […]
Dear all, I am happy to announce new version of phpipam IP address management – version 0.9. 
New features, like Support for ICMP network discovery, ICMP check IP status in demand, Compressed (grouped) DHCP IP ranges and other were introduced. Most important are:
Some instructions on how to setup ICMP scanning will follow.
If you find phpIPAM useful for your company donations would be highly appreciated 
You can demo it here: http://demo.phpipam.net/
You can download it on sourceforge site: phpipam-0.9.
Special thanks to all the people submitting bug reports, translators and feature testers!
Screenshots:
Full changelog for this release is:
New features:
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+ Support for ICMP network discovery;
+ Cron script to check status for selected subnets/hosts with threading suport (pcntl php extension required);
+ ICMP check IP status in demand;
+ Compressed (grouped) DHCP IP ranges;
+ API server version 0.1;
+ Option to show and group subnets by VLAN in subnets list;
+ Option to show and Continue reading
It’s a busy week to say the least. Not only are we a sponsor of the 2nd Open Networking User Group (ONUG) meeting, we held our inaugural Technical Advisory Board (TAB) meeting. Leveraging the fact that many of our customers will be attending ONUG, we brought together some of the most forward-thinking networking and business professionals from enterprises, service providers and partners to talk about our company, our product roadmap and our ideal use cases.
Before I get into the highlights, I’d like to give Embrane a high-five because we can actually have a TAB made up of paying customers. In an industry currently dominated by PowerPoint slides and acronyms, having a shipping product that people are using is unique in its own right. Also, where there was a full day of great feedback and dialogue. I’m just going to cover three aspects of the discussion otherwise I would have to write a novel to capture everything.
Platform vs. Product
One of the liveliest discussions was around the value of Embrane to customers. If you’ve been following the Embrane story, you’ll recall we’ve been focusing our marketing message around application-centric networking and more specifically, as of late, application-centric Continue reading
Recently some time ago (this blog post has also been lying in draft for a while)
someone came to me with a problem they had with a Cisco 7600.
It felt sluggish and "show proc cpu" showed that the weak CPU was very loaded.
This is how I fixed it.
"show proc cpu history" showed that the CPU use had been high for quite a while, and too far back to check against any config changes. The CPU use of the router was not being logged outside of what this command can show.
"show proc cpu sorted" showed that almost all the CPU time was spent in interrupt mode. This is shown after the slash in the first row of the output. 15% in this example:
Interrupt mode CPU time is (a bit simplified and restricted to the topic at hand) used when the router has to react to some user traffic. Now why would the 7600 use the Continue readingRouter# show proc cpu sorted CPU utilization for five seconds: 18%/15%; one minute: 31%; five minutes: 42% PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process 198 124625752 909637916 137 0.87% 0.94% 0.94% 0 IP Input [...]
Ladies and gentleman, prepare to be mystified and amazed by another episode of Healthy Paranoia. Where even the unicorns are nerdy and the evil bit is always set on your packets. Just in time for Halloween, get ready for some tricks and definitely treats, because we’re going to discuss the intersection of magic, social engineering […]
The post Healthy Paranoia Show 18: Illusion, Lies and Neuroscience with Alex Stone appeared first on Packet Pushers Podcast and was written by Mrs. Y.
I had this blog post lying around as a draft for a long time. I didn't think it was was "meaty" enough yet, but since I'm no longer a network consultant I don't think it'll become any meatier. So here it goes.
Here I will describe the process of L3-to-L2 mapping, or next-hop resolution and how it works with point-to-point circuits like PPP, ATM and Frame relay. It's the process of finding out what to actually do with a packet once the relevant routing table entry has been identified.
It's deceptively simpler than on a LAN segment, but since people generally learn Ethernet before they learn point-to-point nowadays I'm writing it anyway.
When a packet is to be sent to an address on the same subnet a L3-to-L2 mapping is done to look up the L2 destination address (if any) to apply.
The packet is then encapsulated in a L2 frame and sent out the interface.
On a normal Ethernet LAN segment ARP is used to look up L3-to-L2, and the frame will then have that (L2) MAC address as its destination. The frame will then be received by (and only by) the intended destination.
In a point-to-point interface there Continue reading
Your company has a border router (R2) that is connected to two partner companies: Partner-DB (R1) providing database services and Partner-APP (R3) that provides different application services to your web servers in DMZ (200.200.200.0/24). You are requested to configure NAT according to some requirements.
How does the internet work - We know what is networking
We will speak here about some basics about Forwarding UDP broadcast traffic. If you were wondering what Forwarding UDP broadcast traffic actually is I will try to explain it here in few words. If you have more that one broadcast domains in your local network, let’s say that you have three VLANs. In normal networking theory it’s normal […]
This was actually spurned from a comment I received on another one of my blog posts that you can find here. Seeing that comment, I white boarded it and realized that I may have been completely wrong in regards to how Root Guard could “break a network”.
Let’s say we have the following topology:
Let’s work through the spanning tree topologies.
Core 1 – Root bridge for VLAN 10. All ports designated.
Core 2 – Port 1 will be a root port Continue reading
