Blog Posts in October 2023

Weird: vJunos Evolved 23.2R1.5 Declines DHCP Address

It’s time for a Halloween story: imagine the scary scenario in which a DHCP client asks for an address, gets it, and then immediately declines it. That’s what I’ve been experiencing with vJunos Evolved release 23.2R1.15.

Before someone gets the wrong message: I’m not criticizing Juniper or vJunos.

  • Juniper did a great job releasing a no-hassles-to-download virtual appliance.
  • DHCP assignment of management IPv4 address worked with vJunos Evolved release 23.1R1.8
  • There were reports that the DHCP assignment process in vJunos Evolved 23.1R1.8 was not reliable, but it worked for me so far, so I’m good to go as long as I can run the older release.
  • I might get to love vJunos Evolved. Boot- and configuration times are very reasonable.

However, it looks like something broke in vJunos release 23.2, and it would be nice to figure out what the workaround might be.

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Worth Exploring: BGP from Theory to Practice

My good friend Tiziano Tofoni finally created an English version of his evergreen classic BGP from theory to practice with co-authors Antonio Prado and Flavio Luciani.

I had the Italian version of the book since the days I was running SDN workshops with Tiziano in Rome, and it’s really nice to see they finally decided to address a wider market.

Also, you know what would go well with that book? Free open-source BGP configuration labs of course¬†ūüėČ

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Early Data-Link Layer Addressing

After covering the theoretical part of network addressing (part 2, part 3), let’s go into some practical examples. I’ll start with data link layer and then move on to networking and higher layers.

The earliest data link implementations that were not point-to-point links were multi-drop links and I mentioned them in the networking challenges part of the webinar. Initially, we implemented multi-drop links with modems, but even today you can see multi-drop in satellite communications, Wi-Fi, or in cable modems.

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BGP Labs: Multivendor External Routers

A quick update BGP Labs project status update: now that netlab release 1.6.4 is out I could remove the dependency on using Cumulus Linux as the external BGP router.

You can use any device that is supported by bgp.session and bgp.policy plugins as the external BGP router. You could use Arista EOS, Aruba AOS-CX, Cisco IOSv, Cisco IOS-XE, Cumulus Linux or FRR as external BGP routers with netlab release 1.6.4, and I’m positive Jeroen van Bemmel will add Nokia SR Linux to that list.

If you’re not ready for a netlab upgrade, you can keep using Cumulus Linux as external BGP routers (I’ll explain the behind-the-scenes magic in another blog post, I’m at the Deep Conference this week).

For more details read the updated BGP Labs Software Installation and Lab Setup guide.

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netlab 1.6.4: Support for Multi-Lab Projects; More BGP Goodies

Features in netlab release 1.6.4 were driven primarily by the needs of my BGP labs project:

Numerous platforms already support the new BGP nerd knobs:

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Video: History of BGP Route Leaks

I’ll be talking about Internet routing security at the Deep conference in a few days, and just in case you won’t be able to make it1 ;) here’s the first bit of my talk: a very brief history of BGP route leaks2.

Note: you’ll find more Network Security Fallacies videos in the How Networks Really Work webinar.

You need at least free ipSpace.net subscription to watch videos in this webinar.
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Will Network Devices Reject BGP Sessions from Unknown Sources?

TL&DR: Violating the Betteridge’s Law of Headlines, the answer is “Yes, but the devil is in the details.

It all started with the following observation by Minh Ha left as a comment to my previous BGP session security blog post:

I’d think it’d be obvious for BGP routers to only accept incoming sessions from configured BGP neighbors, right? Because BGP is the most critical infrastructure, the backbone of the Internet, why would you want your router to accept incoming session from anyone but KNOWN sources?

Following my “opinions are good, facts are better” mantra, I decided to run a few tests before opinionating1.

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Worth Reading: Introduction of EVPN at DE-CIX

Numerous Internet Exchange Points (IXP) started using VXLAN years ago to replace tradition layer-2 fabrics with routed networks. Many of them tried to avoid the complexities of EVPN and used VXLAN with statically-configured (and hopefully automated) ingress replication.

A few went a step further and decided to deploy EVPN, primarily to deploy Proxy ARP functionality on EVPN switches and reduce the ARP/ND traffic. Thomas King from DE-CIX described their experience on APNIC blog – well worth reading if you’re interested in layer-2 fabrics.

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Video: What Is Software-Defined Data Center

A few years ago, I was asked to deliver a What Is SDDC presentation that later became a webinar. I forgot about that webinar until I received feedback from one of the viewers a week ago:

If you like to learn from the teachers with the “straight to the point” approach and complement the theory with many “real-life” scenarios, then¬†ipSpace.net is the right place for you.

I haven’t realized people still find that webinar useful, so let’s make it viewable without registration, starting with¬†What Problem Are We Trying to Solve¬†and¬†What Is SDDC.

You need at least free ipSpace.net subscription to watch videos in this webinar.
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netlab 1.6.2: More Reporting Goodies

netlab release 1.6.2 improved reporting capabilities:

  • BGP reports and IP addressing reports are fully IPv6-aware
  • Some columns in BGP reports are optional to reduce the width of text reports
  • You can filter the reports you’re interested in when using netlab show reports command
  • Reports relying on¬†ipaddr¬†Ansible filter display warnings (instead of crashing) if you don’t have Ansible installed.

In other news:

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