One to read: A Beginner’s Guide to IPFS

One to read: “A Beginner’s Guide to IPFS”

Ever wondered about IPFS (the “Inter Planetary File System”) – a new way to share and store content. This doesn’t rely on a central server (e.g. Facebook, Google, Digital Ocean, or your home NAS) but instead uses a system like bittorrent combined with published records to keep the content in the system.

If your host goes down (where the original content is stored) it’s also cached on other nodes who have visited your site.

These caches are cleared over time, so are suitable for short outages, or you can have other nodes who “pin” your content (and this can be seen as a paid solution that can fund hosts).

IPFS is great at hosting static content, but how to deal with dynamic content? That’s where PubSub comes into play (which isn’t in this article). There’s a database service which sits on IPFS and uses PubSub to sync data content across the network, called Orbit-DB.

It’s looking interesting, especially in light of the announcement from CloudFlare about their introduction of an available IPFS gateway.

It’s looking good for IPFS!

This was automatically posted from my RSS Reader, and may be edited later to add commentary.

One to read: Overview of TLS v1.3

One to read: “Overview of TLS v1.3”

Wondering what TLS v1.3 means to your web browsing? OWASP break it down into what the differences are between TLS1.2 and TLS1.3. It’s a really good set of slides and would be great if you need so show someone some of the moving pieces without reading the RFS (RFC8446). It’s good :)

This was automatically posted from my RSS Reader, and may be edited later to add commentary.

“You can’t run multiple commands in sudo” – and how to work around this

At work, we share tips and tricks, and one of my colleagues recently called me out on the following stanza I posted:

I like this [ansible] one for Debian based systems:
  - name: "Apt update, Full-upgrade, autoremove, autoclean"
    become: yes
    apt:
      upgrade: full
      update_cache: yes
      autoremove: yes
      autoclean: yes

And if you’re trying to figure out how to do that in Shell:
apt-get update && apt-get full-update -y && apt-get autoremove -y && apt-get autoclean -y

His response was “Surely you’re not logging into bash as root”. I said “I normally sudo -i as soon as I’ve logged in. I can’t recall offhand how one does a sudo for a string of command && command statements”

Well, as a result of this, I looked into it. Here’s one comment from the first Stack Overflow page I found:

You can’t run multiple commands from sudo – you always need to trick it into executing a shell which may accept multiple commands to run as parameters

So here are a few options on how to do that:

  1. sudo -s whoami \; whoami (link to answer)
  2. sudo sh -c "whoami ; whoami" (link to answer)
  3. But, my favourite is from this answer:

    An alternative using eval so avoiding use of a subshell: sudo -s eval 'whoami; whoami'

Why do I prefer the last one? Well, I already use eval for other purposes – mostly for starting my ssh-agent over SSH, like this: eval `ssh-agent` ; ssh-add

One to listen to: “Jason Scott is Breaking Out in Archives”

http://sysadministrivia.com/episodes/S3E13

This is a fascinating episode. Jason Scott works for the Internet Archive, personally hosts a large archive of historic BBS text files, and is an engaging interviewee (plus, he talks a lot :) )

If you’re interested in how archive.org works (including how they choose disks for their storage, how content is processed and managed, whether they keep spam, how many hours of “sermons” have been stored, etc), or what happens when you get sued for USD2,000,000,000, it’s well worth a listen.

One to read/watch: IPsec and IKE Tutorial

Ever been told that IPsec is hard? Maybe you’ve seen it yourself? Well, Paul Wouters and Sowmini Varadhan recently co-delivered a talk at the NetDev conference, and it’s really good.

Sowmini’s and Paul’s slides are available here: https://www.files.netdevconf.org/d/a18e61e734714da59571/

A complete recording of the tutorial is here. Sowmini’s part of the tutorial (which starts first in the video) is quite technically complex, looking at specifically the way that Linux handles the packets through the kernel. I’ve focused more on Paul’s part of the tutorial (starting at 26m23s)… but my interest was piqued from 40m40s when he starts to actually show how “easy” configuration is. There are two quick run throughs of typical host-to-host IPsec and subnet-to-subnet IPsec tunnels.

A key message for me, which previously hadn’t been at all clear in IPsec using {free,libre,open}swan is that they refer to Left and Right as being one party and the other… but the node itself works out if it’s “left” or “right” so the *SAME CONFIG* can be used on both machines. GENIUS.

Also, when you’re looking at the config files, anything prefixed with an @ symbol is something that doesn’t need resolving to something else.

It’s well worth a check-out, and it’s inspired me to take another look at IPsec for my personal VPNs :)

I should note that towards the end, Paul tried to run a selection of demonstrations in Opportunistic Encryption (which basically is a way to enable encryption between two nodes, even if you don’t have a pre-established VPN with them). Because of issues with the conference wifi, plus the fact that what he’s demoing isn’t exactly production-grade yet, it doesn’t really work right, and much of the rest of the video (from around 1h10m) is him trying to show that working while attendees are running through the lab, and having conversations about those labs with the attendees.

TCPDump Made Easier Parody Book Cover, with the subtitle "Who actually understands all those switches?"

One to use: tcpdump101.com

I’m sure that anyone doing operational work has been asked at some point if you can run a “TCPDump” on something, or if you could get a “packet capture” – if you have, this tool (as spotted on the Check Point community sites) might help you!

https://tcpdump101.com

Using simple drop-down fields for filters and options and using simple prompts, this tool tells you how to run each of the packet capturing commands for common firewall products (FortiGate, ASA, Check Point) and the more generic tcpdump tool (indicated by a Linux Penguin, but it runs on all major desktop and server OSs, as well as rooted Android devices).

Well worth a check out!