rsync go, NASA SP287, git options, Undersea cable failures in Africa, Quotes, Log4j, done list, Dan Lynch, Systems-based Productivity, Run Africa

rsync go: Interesting talk about rsync, as it explains how it works and it is something I didnt know. But then, all other things/projects mentioned are cool and related. I need to try to install rsync go in my vm. ccc slides and repo

NASA to the moon: This is an engaging and provocative video regarding the Artemis III (project back to the moon II). He makes some hard questions to the people in charge (I have no clue about physics) and it seems he has a point. Not sure it this will get any effect but again, looks “smart”. When he mention the NASA SP287 (What made Apollo a success) document as the grial for going back to the moon, I wanted to get a copy (here) so I could read it one day.

Git options: Nice post about popular git config options. I am a very basic git user (and still sometimes I screw up) but the options to improve diff looks interesting so I will give it a go at work.

Undersea cable failures in Africa: It is clear that Africa relays heavily in submarine cables (it doesnt look like there are many cable systems intra continent). And the Red Sea is becoming a hot area due to different conflicts…

Quotes: I like the ones regarding simplicity:

A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works and cannot be patched up to make it work. You have to start over with a working simple system. (John Gall)

In programming, simplicity and clarity are a crucial matter that decides between success and failure. (Edsger Dijktra)

Log4j: This is old news but when it came out I tried to run the PoC but I failed 馃檨 This is just a reminder. It was annoying because I manged to install all tools but never managed to exploit it.

Done List: I feel totally identified. The to-do list is never done and you feel guilty. Done-list, much healthier.

Dan Lynch: He passed away, and as usual on my ignorance, it seems he is one of the unsung heroes of Internet, migrating ARPANET to TCP/IP.

Systems-Based Productivity: TEMPO refers to five dimensions of productivity: T (Time Management), E (Energy Management), M (Mindset), P (Proficiency) and O (Organization).

Run Africa: very jealous.

Infraops challenge, Devika, Daytona, NTP 2038, Linux Crisis Tools, videos, Chocolonely, LLM, Transformers, Enforce-first

InfraOps challenge: A bit beyond me, but interesting If you could try without applying for the job.

Devika: Agent AI. Another thing I would like to have time to play with it. If you have API keys for some LLMs, looks like it shouldn’t be difficult to run and you dont need a powerful laptop (?)

Daytona: My development environment is a joke, just python envs. But I guess for more serious devs, could be interesting

NTP and year 2038: Agree, when it is not DNS, it is likely NTP (seen this with VPNs and SSL certs in boxes with NTP unsync), or something blocking UDP.

Linux crisis tools: I haven’t got my hands dirty with BPF but I am surprised with so many tools. I would add nc, netstat, lsof, traceroute, ping, vim, openssl etc but because I do pure networks.

Jim Kwik: How to improve your reading speed. One improvement is you use your finger or a ruler. Need to watch again.

Rich Roll: The guy is super chill. I would like to be able to do some ultra at some point in life… Very personal conversation.

Ferran Adria: I didnt know much about the person apart from being one of the best Chefs in history. I like how he starts the interview and take over for 15 minutes. Haven’t watched till the end. But just the beginning is priceless.

Mark Manson: I have read all his books and his emails. Interesting his story.

Chocolonely: I didnt know it was a dutch company and interesting history behind. I want to try one day, but I haven’t found a dark choco version.

LLM in 1000 lines puce C: I was always crap at C. But interesting this project as something educational and intro in LLM.

Visual intro to transformers: The easy joke, unfortunately, this is not about Optimus Prime.

Indonesia Heavy Metal Girls: Unexpected. Respect.

Enforce-first-as: I dint know about this until last week. Cisco defined by default. Juniper disabled by default. And this makes sense with Route Servers.

AI will save the world, Nutanix kernel upgrade, GPU Programming

AI will save the world: Positive view of the AI development. Interesting the attack to China/Karl Marx at the end. In general I feel confident this will be good.

Nutanix kernel upgrade story: This is a bit hardcore for me (and looks a bit old from 2021) but still quite interesting how they did the troubleshooting.

GPU programming: I have never read about how to code for a GPU and this looks interesting and quite different from what I would do in a CPU. From the “Execution Model of the GPU” I started to lose track. Still is nice to see a summary at the end and resources/books.

Life, Love, Sex, Negative Beliefs, startup regrets, nanog90, Groq LPU, LLM from scratch, ssh3, eBFP BGP, RPKI, TIANHE-3

I hit rock bottom this week. I hope I finally closed one door in my life so I give myself the chance to open others. Made the wrong decision? It is easy when you look back. Do I regret it? The most annoying thing is these are failures so you can’t go back and recover. But I was so bloody newbie!!!…. At least after 5 years…

“For every reason it’s not possible, there are hundreds of people who have faced the same circumstances and succeeded.” Jack Canfield

Head down, crying, cursing, whatever, but forwards. As it has always been.


Somehow managed to list to long videos, something I normally can’t manage (because lack of time, etc)

Negative Beliefs, avoid bitterness, aim for greatness (remarkable things), scape the darkness: Jordan B Peterson with Modern Wisdom: video, podcast.

Find and keep Love: video. 1st Get your shit together. Communication is critical. Be careful with your shopping list….

Good Sex: video. Communicate….

Orgasm: video. Haven’t seen it completely yet but very interesting. Use your tongue wisely.

— Other things:

Startup decisions and regrets: page. Interesting. I think most of things are very specific but still good to read.

Nanog90: agenda I didnt want the videos but I reviewed several pdfs and these ones look interesting:

Abstract Ponderings: A ten-year retrospective. Rob Shakir – Google: video

AI Data Center networks – Juniper – video

Using gNOI capabilities to simplify software upgrade use case: video – I had to idea about gNOI so looks interesting. It is crazy that still in XXI, automating a network device is so painful. Thanks to all vendors to make your life miserable.

Go lang for network engineers: video slides– I always thought that Golang had a massive potential for network automation but there was always lack of support and python is the king. So nice to see that Arista has things to offer.

PTP in Meta: video and blog.

There are more things, but havent had the chance to review them.


It looks there is new chatbot that is not using the standard NVIDIA GPU. Groq uses LPU (Language Processing Unit). And they say it is better than a GPU. They have this paper but I can’t really see feature of that LPU.

Slurp’it: Show this blog, and the product looks interesting but although is free, it is not opensource and at the end of they you dont want a new vendor-lockin

Container lab in kubernetes: Clabernetes. I would like to play with this one day.

NetDev0x17: videos and sessions. link This is quite low details and most of the time beyond my knowledge. Again, something to take a look at some point.

LLM from scratch: repo. Looks very interesting. But the book it is going to take a long time to hit the market.

ssh3: repo. Interesting experiment.

eBFP and BGP: blog. Really interesting. Another thing that always wanted to play with.

Orange RPKI: old news but still interesting to see how much damaged can cause RPKI in the wrong hands…

China TIANHE-3 Supercomputer: Very interesting. Link.


I guess there are hundreds of project that try to use GPT to build apps. I found this one and looks very nice. I would like to use it if I find time for one idea.

Curl, Yaml, scalars, Elixir, git stash

I haven’t watched this video, but looks like the holly book of curl!!!

I'd recommend starting at ~34 minutes.

路You can specify multiple URLS with multiple output options in a single command. Doing this or using globbing (see below) to the same host will use persistent connections and greatly improve performance because the same L5 session is used

路trurl is also made by the project and allows you to programmatically manipulate URLs (change server, path, query parameters, etc.). Pretty neat:

路curl supports URL globbing: curl https://{ftp,www,test}[1-22].jpg -o "foo_#2_#1.jpg"

路By default, curl will resolve requests serially when multiple URLS or globbing is specified, but curl is capable of doing parallel transfers with the -Z or --parallel option. And can do anywhere from 2-300 transfers in parallel. This also has the potential to parallel-ize HTTP/3 transfers even from single URLs.

路You can do curl --help category to get a list of help categories for narrowing down options by categories like http or output

路 Long commands for curl can be specified in a file and given to curl either via stdin or -K / --config - These files are essentially just command lines in a file

路You can use the --trace option to provide tcpdump type output from curl. Saving the need to to start tcpdump in the background if you just want to see what's happening from curl

路You can use --connect-to to specify a different DNS name to go to (instead of the one specified in the URL) which is similar to the --resolve option, but doesn't require the user to lookup the IP address ahead of time

路You can override the DNS server that you use to resolve URLs via --dns-ipv4-addr for example

路You can add --libcurl to any curl command and it will spit out C source-code that implements the same command line in C via the library libcurl

路You can set the environment variable SSLKEYLOGFILE to a file name and it will save the runtime TLS secrets to that file, and use that file in WireShark along with a dump of the traffic from tcpdump to see the contents of encrypted HTTP streams

路You can choose to only download files that have changed since the last time they were downloaded with curl via --etag-save <etag_file> and --etag-compare <etag_file>

路You can skip adding the extra -H "Content-Type: application/json" when getting or posting JSON data (with -d), by specifying --json instead of just -d

路You can create JSON easily from the command line with the tool jo: (basically a reverse jq)

Rant about yaml. And something I learned about yaml some months ago and forgot about it: scalars for making multiline work in yaml.

Elixir: a programming language based on Erlang. Really impressive reports! But still I would like to learn golang (if I ever learn properly python 馃檪

git stash: I didnt know about this git command until last week, very handy.

Python: cycle and setattr

This week a colleague refactor a script that I wrote and the end was pretty different from what I did. The logic was the same but the code was very differnt. I learnt two things about python

setattr: This method provides an alternate means to assign values to class variables, in addition to constructors and object functions. It comes in handy when we want to add a new attribute to an object and assigning it a value
cycle: . This function takes an iterable聽inputs聽as an argument and returns an infinite iterator over the values in聽inputs聽that returns to the beginning once the end of聽inputs聽is reached.聽

API scripts: CML and Vsphere

In the last months I have been trying to practice the knowledge from CCNA DevNet and managed to wrote very basic scripts using API.

CML is a simulation solution from Cisco that actually works (you have to pay and need hardware). There are nice docs out there:

CML sandbox

CML Starting guide + API examples (this saved me)

CML simulation lifecycle example (havent tried yet)

CML: I actually struggled in this one regarding how to authenticate….. Checking some pages I worked out. I was trying to use the theory from DevNet but no joy. The idea is to restore a lab after you have made many changes. The script log into CML, delete the lab and restore with a provided backup.

Some docs for vsphere api:

Vsphere create session: (quite useful)

vcenter REST API authentication

vcenter API with Postman

Vsphere postman examples (need to take a look)

Vsphere: This is even simpler…. at least in this one I didnt struggle with the auth as the documentation was quite clear. But the original goal of restore a VM from a snapshot looks like is not available via API.

CCNA DevNet Notes

1) Python Requests status code checks:

r.status_code ==

2) Docker publish ports:

$ docker run -p ubuntu bash

This binds port 8080 of the container to TCP port 80 on of the host machine. You can also specify udp and sctp ports. The Docker User Guide explains in detail how to manipulate ports in Docker.

3) HTTP status codes:

1xx informational
2xx Successful
 201 created
 204 no content (post received by server)
3xx Redirect
 301 moved permanently - future requests should be directed to the given URI
 302 found - requested resource resides temporally under a different URI
 304 not modified
4xx Client Error
 400 bad request
 401 unauthorized (user not authenticated or failed)
 403 forbidden (need permissions)
 404 not found
5xx Server Error
 500 internal server err - generic error message
 501 not implemented
 503 service unavailable

4) Python dictionary filters:

my_dict = {8:'u',4:'t',9:'z',10:'j',5:'k',3:'s'}

# filter(function,iterables)
new_dict = dict(filter(lambda val: val[0] % 3 == 0, my_dict.items()))

print("Filter dictionary:",new_filt)

5) HTTP Authentication

Basic: For聽"Basic"聽authentication the credentials are constructed by first combining the username and the password with a colon (aladdin:opensesame), and then by encoding the resulting string in聽base64聽(YWxhZGRpbjpvcGVuc2VzYW1l).

Authorization: Basic YWxhZGRpbjpvcGVuc2VzYW1l

auth_type = 'Basic'
creds = '{}:{}'.format(user,pass)
creds_b64 = base64.b64encode(creds)
header = {'Authorization': '{}{}'.format(auth_type,creds_b64)}


Authorization: Bearer <TOKEN>

6) “diff -u file1.txt file2.txt”. link1 link2

The unified format is an option you can add to display output without any redundant context lines

$ diff -u file1.txt file2.txt                                                                                                            
--- file1.txt   2018-01-11 10:39:38.237464052 +0000                                                                                              
+++ file2.txt   2018-01-11 10:40:00.323423021 +0000                                                                                              
@@ -1,4 +1,4 @@                                                                                                                                  
  • The first file is indicated by聽—
  • The second file is indicated by聽+++.聽
  • The first two lines of this output show us information about聽file 1聽and聽file 2. It lists the file name, modification date, and modification time of each of our files, one per line.聽
  • The lines below display the content of the files and how to modify聽file1.txt聽to make it identical to聽file2.txt.
  • -聽(minus) 鈥 it needs to be deleted from the first file.
    +聽(plus) 鈥 it needs to be added to the first file.
  • The next line has two at sign聽@聽followed by a line range from the first file (in our case lines 1 through 4, separated by a comma) prefixed by “-“聽and then space and then again followed by a line range from the second file prefixed by聽“+”聽and at the end two at sign聽@. Followed by the file content in output tells us which line remain unchanged and which lines needs to added or deleted(indicated by symbols) in the聽file 1聽to make it identical to聽file 2.聽

7) Python Testing: Assertions

.assertEqual(a, b)	a == b
.assertTrue(x)	        bool(x) is True
.assertFalse(x)	        bool(x) is False
.assertIs(a, b)	        a is b
.assertIsNone(x)	x is None
.assertIn(a, b)	        a in b
.assertIsInstance(a, b)	isinstance(a, b)

*** .assertIs(), .assertIsNone(), .assertIn(), and .assertIsInstance() all have opposite methods, named .assertIsNot(), and so forth.


This is something I have heard about in the past but never used. So this week, as finally decided to write a script to help me to find the peers of flapping ports, learned about pandas from first time. I used another script as “inspiration” and after seeing it was using pandas, I decided to read a bit about it and give it a go.

The main type is the DataFrame. In my head, pandas is just a library to deal with CSV, spreadsheets, etc like when you use a program like libreoffice. And this page, gave me the hints for creating the query I wanted to make.

So at the end I have my very basic script but saves me time logging to each device and find the peer port.

Of course, there are different ways to tackle this problem, but in my environment, the source of truth for links is in a file. You could have that info in the port description too, or in a database, etc.

$ python3 -f flapping-list.txt

SW1 Ethernet1/1 SW2 Ethernet1/1
SW1 Ethernet1/4 SW2 Ethernet1/4

$ cat flapping-list.txt 
$ cat patching-file.csv 
Site,Source Device,Source Interface,Destination Device,Destination Interface,Media