Valter Popeskic
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Valter Popeskic
Redistribute Static on Juniper & Cisco
How Does Internet Work - We know what is networking
In case you wondered how to redistribute static routes into dynamic routing protocol you are at the right place. This is normally a basic thing to do, but I will let you know how to do it in different ways on different vendor devices so it might be interesting. We will go through few examples of normal static to OSPF redistribution and then see how it can be partially done with only part of static routes using route filters. I’ll do it on Cisco and Juniper devices so we can see what’s the difference. Cisco In Cisco CLI, redistribute static
Enable Source-Specific Multicast in Iperf
How Does Internet Work - We know what is networking
I was preparing lab environment to test configuration of Source-Specific Multicast on Juniper SRX Equipment and needed a tool to generate and measure Source-Specific Multicast streams. I was aware that Iperf is a good enough tool to generate and measure multicast and unicast traffic but support for SSM was missing from current version. Fortunately there are always some developers which are interested in networking so one of them developed a special Iperf version 2.0.5 with SSM support. The idea here is to show how to make this version of Iperf work on your Cent OS or similar Linux machine. Here
Source-Specific Multicast Configuration
How Does Internet Work - We know what is networking
In SSM, Source-Specific Multicast, things are done differently from standard multicast forwarding. SSM is specifying a group of hosts that are receiving same multicast stream using group IP address and additionally using stream unicast source IP. In this article it is shown how to configure Source Specific Multicast on Cisco and Juniper equipment. In standard multicast, forwarding is done using group IP address which is an IP from multicast dedicated range 224.0.0.0/4 (224.0.0.0 – 239.255.255.255) or FF00::/8 in IPv6. Each multicast group IP address is a single address which specifies all hosts receiving a specific stream, streamed towards that group
QKD – How Quantum Cryptography Key Distribution Works
How Does Internet Work - We know what is networking
QKD – Quantum key distribution is the magic part of quantum cryptography. Every other part of this new cryptography mechanism remains the same as in standard cryptography techniques currently used. By using quantum particles which behave under rules of quantum mechanics, keys can be generated and distributed to receiver side in completely safe way. Quantum mechanics principle, which describes the base rule protecting the exchange of keys, is Heisenberg’s Uncertainty Principle. Heisenberg’s Uncertainty Principle states that it is impossible to measure both speed and current position of quantum particles at the same time. It furthermore states that the state of observed particle will change if and
Unable to access Cisco ASA through AnyConnect VPN?
How Does Internet Work - We know what is networking
I stepped on this issue few weeks ago. I was implementing a new ASA Firewall solution, first time for me with software newer than version 8.4.2 It seems that all those stories about changes in the NAT logic after that version were true. This is what I found out about ASA packet processing. Configuration was really straightforward and everything worked fine except one thing. When connected remotely using Cisco AnyConnect I was able to access all devices inside the network (inside ASA firewall), but not the ASA itself. I wasn’t able to connect with SSH nor with ASDM. I, of course,
Introduction to Quantum Cryptography
How Does Internet Work - We know what is networking
Quantum cryptography is a new technique of securing computer network communication channel. Existing standard crypto systems are using advanced algorithms to create key pairs which are extremely hard to inverse engineer. Quantum cryptography avoids any mathematical algorithm and uses principles of quantum physics. Quantum crypto implements a new technique of generating and exchanging crypto keys which makes it impossible for third party entities to get those keys by snooping or to create man in the middle by snooping and sending copies of original key. Keys generated in this way will automatically destroy themselves if read by third-party interferer. When generated between two sides, using quantum key distribution, secret keys will
Cryptography
How Does Internet Work - We know what is networking
If you want to send or store data and be sure it is safe from being intercepted, you will use Cryptography. Cryptography uses chipper as mathematical virtual lock to make data scrambled so that is not understandable if intercepted by unauthorized third parties. There are different cryptography techniques, some of them are: encryption, hashing, and steganography. Cryptography can be differentiated by usage of different key types: Symmetric Key Encryption Asymmetric Key Encryption Symmetric Key Encryption is sometimes known as Secret Key Cryptography. Main characteristic of this type of cryptography is the same key usage in encryption and decryption of transferred
ICANN and the future of DNS and internet
How Does Internet Work - We know what is networking
I sorry to put here something that is not really technical but with a blog with the name “howdoesinternetwork.com” it would be strange not to follow the story about the future of DNS governance giving the fact that DNS is a crutial part of internet functionality. You probably know how the internet works giving the fast that you are visiting a blog like this. Regardless of that, it will not hurt to explain in few words the importance of DNS (Domain Name System) for normal internet operation. Let’s surf to se how this works If you want to open this webpage
ISSU Upgrade of Cisco Catalyst 6880-X VSS Cluster and 6800ia FEX extenders
How does Internet work - We know what is networking
I wrote all the details about ISSU procedure steps and explained each step extensively. For a shorter update procedure guide check abbreviated article: Short list of upgrade steps without extensive explanations “Cisco Catalyst 6880-X VSS ISSU Upgrade Steps“ Intro Cisco spoiled us over the years with great and detailed documentation on each technology and hardware component they support. Still, I managed to find a part where documentation is not detailed enough to give you definite number of steps to get things done. While preparing for software upgrade of Cisco Catalyst 6880-X VSS cluster I stumbled on one of the first examples of
ISSU Upgrade of Cisco Catalyst 6880-X VSS Cluster and 6800ia FEX extenders
Cisco Catalyst 6880-X VSS ISSU Upgrade Steps
How does Internet work - We know what is networking
I wrote extensively about ISSU procedure steps in the article: “ISSU Upgrade of Cisco Catalyst 6880-X VSS cluster and its four 6800ia FEX extenders“ This is a short version without comments and explanations for those that need to get things done quickly without reading through my extensive waffle. Let’s start! 1. Get the info on which IOS version is supported to be upgraded with ISSU Google for ISSU or EFSU IOS upgrade support or use this Cisco doc “SX_SY_EFSU_Compatibility_Matrix1” to select supported IOS for ISSU upgrade from your current version. 2. Upload IOS to both Chassis copy ftp://admin:[email protected]/c6880x-adventerprisek9-mz.SPA.151-2.SY7.bin bootdisk: and
Juniper vMX Lab Setup on VMware
How does Internet work - We know what is networking
This is a description on how to deploy a Juniper LAB of 8 vMX routers and making a simple topology in VMware vSphere environment. vMX is Juniper’s virtual production router so this could be the same procedure for deploying vMX device in production except different number of routers and their interconnection with vSwitch setup. As you might have seen from my previous post, I’m trying to get into Juniper configuration lately. One of the things that I needed is to set up a simple lab running Juniper vMX machines with multicast forwarding enabled. It was a simple lab experiment with few commands on each device.
Juniper vMX Multicast Configuration
How does Internet work - We know what is networking
I’m fairly new to Juniper CLI. For one of my first tries, I decided to make my life difficult by starting with multicast configuration on virtual vMX routers running as VMs on VMware ESXi. It took a lot of investigation about some part of this configuration specially the tunnel interface which you will see below. I decided to put it here all in one place with the explanation of every step because Juniper documentation tends to assume that you know more than me. If that is not the case, this short description is for you. Here’s how the topology looks like. I have
WoL – Wake On LAN
How does Internet work - We know what is networking
For WoL to work, configuration needs to be done on two sides, on the VLAN10 where server is connected, so that magic packets can be sent, and on the client side VLAN11 to enable that magic packets can be delivered to clients.
Network Virtualization
How does Internet work - We know what is networking
Virtualization of network devices and path isolation is achieved with VRF on the routers, VLANs separate switch port groups into separate broadcast domains
INE v5 Full-Scale Practice Lab1 TS GNS3 topology
How does the internet work - We know what is networking
Few days ago I added an article with Config GNS3 topology for newly published INE Routing and Switching Workbook v5 Full-Scale LAB1. Here’s now the topology with starting config of TS section for LAB1. I will not insert here any of my stories today as the same article was published before but with other topology files so if you would like more info, just go to previous post INE R&Sv5 Workbook Full-Scale Practice Lab1 made in GNS3 DOWNLOAD Everything should work fine in this lab except OSPF Loop-Free Alternate Fast Reroute which is not supported so you will be unable
When they throw a Cisco guy to do something with HP networking gear
How does the internet work - We know what is networking
…There’s a nice little pdf to get you through HP is aware that most of networking engineers start their learning process in Cisco Networking Academy. Is is a normal course of events if you want to learn networking. Cisco has the very best study materials and best, carefully developed syllabus that is both high quality […]
When they throw a Cisco guy to do something with HP networking gear
INE R&Sv5 Workbook Full-Scale Practice Lab1 made in GNS3
How does the internet work - We know what is networking
Yesterday INE finally added a Full-Scale LAB in their new CCIE Route and Switching blueprint 5 workbook. I realized this morning that you maybe don’t want to spend half of your day (like me) configuring this topology in GNS3. Better to just take it from here and start your lab right away. In my study […]
What is the difference between tunnel | transport mode in IPsec
How does the internet work - We know what is networking
Intro IPsec making VPN connection possible. I enables to basically simulate a leased line across public Internet and thus enable us to get secure connection across unsecured environment. It enables encryption, authentication and protection of our data when sent across insecurity of the world’s biggest internetwork – Internet. It’s the cheap way to simulate a leased […]
What is the difference between tunnel | transport mode in IPsec
/31 subnet in point-to-point links. Is that possible?
How does the internet work - We know what is networking
On point to point links we actually do not need special broadcast address of that subnet because there's only one way you can send a packet across point to point link.
BGP dampening – punishment for unstable BGP prefixes
How does the internet work - We know what is networking
BGP prefix flapping can be caused by different issues in network. Basically every unstable network where links are unreliably and are going up and down here and there can cause BGP prefix flapping. Every prefix flap will cause some networks to became unreachable. BGP process will then need to recalculate best-path in order to hopefully […]