Netlink is a Linux Kernel interface that is used to talk Networking between Kernel processes, or from userland to Kernel processes. This post documents how I tamed Netlink and make working with it in Golang easier.
If you want to create an interface, set an MTU, set an IP address …
Netlink is a Linux Kernel interface that is used to talk Networking between Kernel processes, or from userland to Kernel processes. This post documents how I tamed Netlink and make working with it in Golang easier.
If you want to create an interface, set an MTU, set an IP address etc... on a Linux machine then you have to talk Netlink to do it. For Golang, there are a number of libraries, but this one seems to be gaining a lot of traction recently. Honorable mentions go to Tenus and Docker's libcontainer.
Now, this library is good, but it isn't complete and some of the behavior I need is missing. So how does one go about implementing it you might ask?
Here's my process:
iproute2 source codeThe iproute2 utility is insanely useful - it replaces ifconfig and route for those with memories long enough.
In my case, the feature I wanted was here and I could take a look at the exact message structure required :)
Once I'd written my tests and code, I wasn't surprised to see that things were not working.
strace will get you part of the way, but it's Continue reading
Netlink is a Linux Kernel interface that is used to talk Networking between Kernel processes, or from userland to Kernel processes. This post documents how I tamed Netlink and make working with it in Golang easier.
This post describes how load sharing and faster convergence in MPLS VPNs is possible by using an unique RD per VRF per PE. It assumes you are already familiar with MPLS but here is a quick recap.
The Route Distinguisher (RD) is used in MPLS VPNs to create unique routes. With IPv4, an IP address is 32 bits long but several customers may and probably will use the same networks. If CustomerA uses 10.0.0.0/24 and CustomerX also uses 10.0.0.0/24, we must in some way make this route unique to transport it over MPBGP. The RD does exactly this by prepending a 64 bit value and together with the IPv4 address, creating a 96-bit VPNv4 prefix. This is all the RD does, it has nothing to do with the VPN in itself. It is common to create RD consisting of AS_number:VPN_identifier so that a VPN has the same RD on all PEs where it exists.
The Route Target (RT) is what defines the VPN, which routes are imported to the VPN and the topology of the VPN. These are extended communities that are tagged on to the BGP Update and transported over MPBGP.
MPLS uses Continue reading
As some of my readers know, I’ve done a fair bit of bike touring. Two of the challenges of bike touring are riding uphill, and riding into headwinds.
Riding uphill is tough. 2,300m passes in snow, or 3,200m passes in sunshine, it’s tough going. But you put your head down, and keep turning the pedals, because you know that eventually you will reach the top, and there will be a downhill reward.
Riding into headwinds is a different story. You can battle into headwinds for days, and never get any reward. It saps your energy, and you don’t know if or when it will ever end. The wind could just keep coming from that direction. I’ve gone to different countries just to avoid the wind in the past.
They’re both hard. But one of them has an end, and a reward. The other one can just keep on sucking away your will to live.
This applies to the rest of your life. The tricky bit is that sometimes you don’t know if you’re going uphill, or into the wind. Both of them feel hard, and you can’t always see the end in sight.
For some time I have had issues while doing captures such as finding the elusive “spare laptop” you can use, multiple trips out to the site to pick up the captures, or finding another NIC to put in there so you can connect remotely and copy the captures over the network, taking up 2 switch […]
The post Raspberry Pi RSPAN Capture Box appeared first on Packet Pushers Podcast and was written by Daniel Himes.
How does Internet work - We know what is networking
This is the story on how I became CCIE# 46173 To be honest, when I look back, I do not really know the main reason behind going through all this trouble, but I can tell you the story about how I did it. It’s mostly a thriller, and some drama towards the end. I will give you an overview of the whole process including the materials used, videos watched, books read and struggles that I went through. I think that is the right thing to do. This article is for all of you out there who are still trying to study for this exam and need some suggestions.
Dmitri Kalintsev, one of the networking guys from VMware NSX team, has kindly agreed to do an NSX technical deep dive Software Gone Wild episode… and you have the opportunity to tell him what you’d like to hear. It’s as easy as writing a comment, and we’ll pick one of the most popular topics.
Do keep in mind that we plan to do a technical deep dive, and it has to fit within an hour or so or nobody will ever listen to it, so please keep your suggestions focused. “Troubleshooting NSX”, “NSX Design”, or “NSX versus ACI ” is not what we’re looking for ;)
I had a fantastic time at Network Field Day 8, and now I’ve been lucky enough to be invited back to NFD9 this February.
As usual, the Tech Field Day crew have put together a great mix of vendors. I particularly like the look of the SDN WAN-focused vendors, such as VeloCloud and cloudgenix. Much of the early SDN focus has been on the DC use-case, but that has limited applicability in my local market. SDN WAN solutions definitely apply to the New Zealand market though. I can think of several organisations where I’d love to have better WAN options today.
I’m also very happy to see Cumulus Networks making a first appearance. I’ve done a lot of Linux work during my career, and there’s many times I would have loved to have all the capabilities of a GNU/Linux environment on a switch. I think they will have a huge influence on how Network OSes are delivered in future.
Network Management has always been a large part of my career too, so I’m looking forward to hearing updates from SolarWinds, and to find out more about NetBeez.
There’s some old faces and new attending. I’m looking forward to meeting people who I’ve Continue reading
Curt Beckmann, CTO for EMEA at Brocade, joins Packet Pushers Ethan Banks & Greg Ferro for an update of what’s been going on with the Forwarding Abstractions Working Group (FAWG) at the Open Networking Foundation (ONF). We get into a discussion of emerging Table Type Patterns within OpenFlow (OF), a way for OF switches and OF […]
The post Show 220 – OpenFlow + Table Type Patterns with Curt Beckmann appeared first on Packet Pushers Podcast and was written by Ethan Banks.
It’s a new year, but some things never change. In the past few days we have observed a spate of incidents of routing misbehavior including two man-in-the-middle routing hijacks conducted in the past couple of days by A2B Internet out of the Netherlands.
Beginning at 00:33:44 UTC on Thursday, 8 January, we began observing a routing hijack of IP address space normally announced by Mada Telecom (AS51047), a Palestinian ISP with presence in both Gaza and the West Bank. Beginning at that time, A2B Internet B.V. (AS51088) began announcing 46.244.81.0/24, which is a more-specific route of 46.244.80.0/23, normally announced by Mada.
Traceroutes directed to this address space are presently being re-directed to A2B Internet’s network in the Netherlands before continuing on to Palestine. For example:
trace from Cyberjava, Malaysia to Mada Telecom, PS on Jan 09, 2015
1 *
2 x.x.x.x (Cyberjaya, Malaysia) 3.442
3 113.23.163.57 (Extreme Broadband, Malaysia) 0.696
4 113.23.190.109 (Extreme Broadband, Malaysia) 1.222
5 218.189.12.101 global.hgc.com.hk 35.854
6 218.189.8.102 global.hgc.com.hk 36.742
7 118.143.224.243 (Hutchison, Singapore) 41.628
8 218.189.8.142 (Hutchison, Amsterdam) 190.787
9 195.219.150.6 (Tata, Amsterdam, NL) 213.494
10 46.244.0.4 (A2B Internet, NL) 200.990
11 141.136.97.5 (GTT, Amsterdam) 268.366
12 4.68.70.97 xe-5-0-1.edge3.Amsterdam.Level3.net 300.909
13 4. Continue readingPlease Join us in congratulating the following iPexpert client who has passed his CCIE lab!
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!
Happy New Year! The year is off to a great start and we are excited to see what 2015 will bring to the networking space. I have a few predictions of my own (think policy and disaggregation) that were recently published in Network World. What are your networking predictions for 2015? Below are our top picks for networking stories this week.
In this week’s PlexxiTube #FBF (Flashback Friday) video of the week, Dan Backman interviews VMworld 2014 attendees and asks what they’ve done to help their networks accommodate to Big Data.
Network World: SDN, data center predictions for 2015
By Jim Duffy
The predictions for data center and SDN in 2015 are still rolling in. Technology Business Research says software will pervade the data center while start-up Plexxi believes policy and disaggregation will be front and center. Here’s the link to TBR’s 2015 Data Center Predictions. Some of the more interesting prognostications in it are the acceleration of SDN in the enterprise and the ability of hyperconvergence to converge.
Network Computing: 10 SDN Startups On The Cutting Edge
By Marcia Savage
Small companies flush with VC money have led the way in software-defined networking. Here are 10 of the hottest Continue reading
I got some questions about how to configure Mikrotik to act as L2TP Server with IPsec encryption for mobile clients. I know this is not exactly in the line of this blog oriented on enterprise networks, but it’s network technology in the end so I’ll try to cover it here.
Orhan Ergun and Neil Moore talked about CCIE Preparation on the packetpushers podcast. Neil Moore is only 8xCCIE in the world and well known geek and HP fellow. Which exam is the hardest ? What are their advises ? Which certification should be received first, what should be the order ? CCIE vs […]
The post CCIE R&S,SP,Wireless,Collaboration,Datacenter,Security Preparation Recommendations appeared first on Network Design and Architecture.
One of the interesting challenges in the Software-Defined Data Center world is the integration of network and security services with the compute infrastructure and network virtualization. Palo Alto claims to have tightly integrated their firewalls with VMware NSX and numerous cloud orchestration platforms - it was time to figure out how that’s done, so we decided to go on a field trip into the scary world of security.
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