Smart engineers were forever using Linux (in particular, its traffic control/queue discipline functionality) to simulate WAN link impairment. Unfortunately, there’s a tiny hurdle you have to jump across: the tc CLI is even worse than iptables.

A long while ago someone published a tc wrapper that simulates shitty network connections and (for whatever reason) decided to call it Comcast. It probably does the job, but I would prefer to have something in Python. Daniel Dib found just that – tcconfig – and used it to simulate WAN link behavior on VMware vSphere.

Bruce Davie collected numerous articles describing various aspects of early Internet history and pre-Internet days, including A Brief History of the Internet and The Design Philosophy of the DARPA Internet Protocols.

Have fun ;)

Justus sent me an email with an interesting link:

Since you love to make comparisons to the good ol’ thick yellow cable while I as a mid-30 year old adult have no idea what you are talking about: Computerphile made a video about Ethernet on the occasion of its 50th birthday. The university of Nottingham got the chance to show their museum pieces :-) (about 8:45 min).

Thanks a million!

Emile Aben is describing an interesting behavior observed in the Wild West of the global Internet: someone started announcing BGP paths with an unknown attribute, which (regardless of RFC 7606) triggered some BGP session resets.

One would have hoped we learned something from the August 2010 incident (supposedly caused by a friend of mine 😜), but it looks like some things never change. For more details, watch the Network Security Fallacies and Internet Routing Security webinar.

On the Communications of the ACM web site, Bertrand Meyer argues that (contrary to the exploding hype) AI Does Not Help Programmers:

As a programmer, I know where to go to solve a problem. But I am fallible; I would love to have an assistant who keeps me in check, alerting me to pitfalls and correcting me when I err. A effective pair-programmer. But that is not what I get. Instead, I have the equivalent of a cocky graduate student, smart and widely read, also polite and quick to apologize, but thoroughly, invariably, sloppy and unreliable. I have little use for such supposed help.

Ignas Bagdonas sent a phenomenal summary of recent BGP developments to the RIPE Routing WG mailing list. Enjoy!

Found an interesting article describing the shenanigans of a biotech startup. Admittedly, it has nothing to do with networking apart from the closing paragraph…

But people will find all sorts of ways to believe what they want to believe, to avoid hearing things that they don’t want to hear, and to avoid thinking about things that are too worrisome to contemplate.

… which is a perfect description of why people believe in centralized control planes, flow-based forwarding, or long-distance vMotion.

Long story short: it’s time for another summer break, as people reporting my bloopers – THANK YOU!!! – know only too well. I plan to be back in early autumn rolling out tons of new content.

I’ll do my best to reply to support requests (it will take longer than usual), and probably won’t be able to resist publishing a few lightweight netlab-related blog posts. If you get bored there’s still over 400 hours of existing content, over 100 podcast episodes, and thousands of blog posts.

An anonymous commenter asked this highly relevant question about my Internet routing security lab:

What are the smallest hardware requirements to run the lab?

TL&DR: 2 GB RAM, 2 vCPU

Now for the more precise answer (aka “it depends”).

After I published the Source IP Address in Multicast Packets blog post, Erik Auerswald sent me several examples of network devices sending IP packets with source IP address set to 0.0.0.0:

• Cisco wireless access points using 0.0.0.0 as the source IP address in VRRP packets.
• Extreme (formerly Avaya) switches sending IGMP queries with source IP address 0.0.0.0 on VLANs on which they have no IP address.