This is the detailed log of the things (mostly technical) I got to learn during my internship with RENU (Research and Education Network for Uganda). RENU is Uganda's National Research and Education Network (NREN). You can see the Summarised Table of my time at RENU here.
- RENU history
- 2006: the birth of RENU
- 2008: UbuntuNet Alliance member
- 2010: UCC License
- 2023: 500th site connected
- RENU Ecosystem
- Global
- RREN - UbuntuNet Alliance
- NREN - RENU
- RENU operations
- RENU board
- RENU secretariat
- Service: RENU Identity Federation, Connectivity, eduroam, eduVPN, Web hosting, Cloud, turnitin, etc
- To deepen my technical Skills
- Get to apply the theoritical knowledge from Campus
- Meet and learn from experts in the field
- Assigned to the Technical Department (Networking, systems, and software)
- VMs
Ah ha!Got to learn that Virtualbox(from oracle) and VMware(from VMWare inc) are different virtualization software. It now sounds obvious.
- Install Debian and windows server 2019 on VMS
-
SSH
-
SSH supports 2 forms of authentication
PasswordandPublic key.Public-keyis more secure. I had to disable Password Authentication on the VMs.#PasswordAuthentication no -
Wrote a script to generate RSA ssh keys
#!/bin/bash # Set the file path for the SSH key pair key_path="$HOME/.ssh/id_rsa" # Generate an RSA key pair without a passphrase # -t rsa: Specifies the key type as RSA # -f "$key_path": Specifies the file path and name for the key pair # -q: Enables quiet mode, suppressing unnecessary output # -C "comment" # -P "": Sets an empty passphrase ssh-keygen -t rsa -f "$key_path" -q -P "" echo "SSH key pair generated successfully."
-
-
Public vs private keys
-
Read about RSA
RSA (Asymetric Encryption Algorithm) Its security lies in the difficulty of factoring semi prime numbers*
SCPis a command-line tool in Linux used to securely transfer files between local and remote systems over a secure SSH (Secure Shell) connection. It allows users to copy files and directories securely between different hosts without the need for additional setup or software.$ scp filename charles@remote_ip:/home/charles/ # changed port from default(22) port, to lets say 5000 $ scp -P 5000 cool_file.py charles@remote_ip:/home/charles/cool_folder
- Unix, BSD, Linux (Unix like / *nix/ POSIX)
- Files Systems
- The linux Distribution Timeline
I got to look at the linux Distro timeline, got to learn of the Debian branch with some of the common Operating systems including Ubuntu, Kali, Tails
Minix(Mini Unix) - unix-like Os based on a microkernel architecture
| Operator | Description |
|---|---|
& |
allows you to run commands in the background of you terminal |
&& |
allows you to combine multiple commands together in one line of your terminal |
; |
execute commands in order. difference with && is that it will execute next command even if the previous command was unsuccessful |
< |
(input redirector) - can take the file as input of a command. |
> |
(output redirector) - can take the output from a command and dirrect it elsewhere |
>> |
same function as > but appends the output rather than replacing |
| |
allows you to redirect the output of one command as the input to another command |
|| |
execute the next command if the first one fails |
{..} |
group commands |
Git, GitHub, BitBucket
(session with Claire)
Types of Virtualization
- Desktop
- Network
- Storage
- Network Attached Storage (NAS) and Storage Area Network (SAN)
RENU runs hundreds of VMs for its members, how can you automate the process of installing the OS. how to provision a VM at the push of a button.
Line of thought
- Configuration Management Tools [
Ansible,Chef,Puppet] - Preseed files, Kickstart files
VBoxManage -> command line interface to Oracle's VirtualBox
Pi-hole is a Linux network-level ad and Internet tracker blocking application that acts as a DNS sinkhole and optionally a DHCP server, intended for use on a private network
Resource: https://www.youtube.com/watch?v=xftEuVQ7kY0&t=540s
Talk from Dr. Ivan Walulya
Talk from Brook
Knowledge Areas
- Networking
- Malware analysis
- Incident analysis
- Cyber etiquette
Mainly daily tasks: Monitor and analyze the network
- L1: focus alert triaging
- L2: typically handle escalated threats
- L3: Escalations from L2
(session with Clinton)
(session with Fahadi)
- BGP runs over
TCPport 179 - Internal BGP
iBGPvs External BGPeBGP - used for exchanging routing and reachability information among
ASes
(session with Arthur)
Google Cache: in RENU's data center to store and deliver cached content for faster access.
ODF (Optical Distribution Frame): provides centralized location for the termination, splicing, interconnection of optical fibres.
(session with Nicholas Brain)
Telecommunication = Distant communication
SSID (Service Set Identifier): a unique name that identifies a specific Wi-Fi network.
ISM (Industrial, Scientific, Medical bands)
band = collection of frequencies
(session with Fred)
Scripting = process of writing a series of instructions or commands that can be executed by a computer to automate tasks or perform specific actions.
Popular Scripting Language
- Bash
- Python
- Powershell
- Others
#!/bin/bash - shebang
cron = chronos (Greek for time)
A cron is a time-based job scheduler in unix-like OS.
Why cron:
- System maintence
- Backups
- Data synchronization
- Report generation
- more...
Crontab (Cron Table) - reads a configuration file.
crontab -e: edit current user's cron jobs
crontab -l: view current user's cron jobs
0 7 * * * curl http://charleskasasira.me/send_good_morning_sms/
@reboot echo "Welcome Charles"
- Cacti
- LibreNMS
- Nagios
(session with Nicholas Brian)
- PEP8
- Flake8
- Coverage
- Write a github action (yml) to check if debug is
TrueorFalse
name: Check Debug Setting
on:
pull_request:
branches:
- main
jobs:
check_debug:
runs-on: ubuntu-latest
steps:
- name: Checkout code
uses: actions/checkout@v2
- name: Set up Python
uses: actions/setup-python@v2
with:
python-version: 3.9
- name: Install dependencies
run: pip install -r requirements.txt
- name: Set environment variable for GitHub Actions
run: echo "GITHUB_ACTIONS=true" >> $GITHUB_ENV
- name: Run Debug Check
id: debug_check
run: python check_debug_setting.py
# If the script fails (non-zero exit status), stop the workflow and prevent merging.
- name: Check Debug Script Result
if: steps.debug_check.outputs.outcome != 'success'
run: echo "Debug check passed. Proceeding with merging the pull request."A centralally-maintained file, distributed to all host on the internet was the first solution of DNS. We still have the /etc/hosts - local DNS.
- The disadvantage with this is that it doesn't scale.
Root Servers (.)
├── TLD Servers (.ug, .uk, .sa, ...)
│ ├── Authoritative Servers (renu.ac.ug)
│ └── ...
├── TLD Servers (.me, .com, ...)
│ ├── Authoritative Servers (charleskasasira.me)
│ └── ...
└── Authoritative Servers (example)
Currently .ug and .ac.ug server is run by I3C, owned by Mr. Charles Musisi
DNS isn't just for websites though, and multiple types of DNS record exist. We'll go over some of the most common ones that you're likely to come across.
- A Record: These records resolve to IPv4 addresses, for example 104.26.10.229
- AAAA Record: These records resolve to IPv6 addresses, for example 2606:4700:20::681a:be5
- CNAME Record: These records resolve to another domain name.
- MX Record: These records resolve to the address of the servers that handle the email for the domain you are querying. These records also come with a priority flag. This tells the client in which order to try the servers, this is perfect for if the main server goes down and email needs to be sent to a backup server.
- TXT Record: TXT records are free text fields where any text-based data can be stored. TXT records have multiple uses, but some common ones can be to list servers that have the authority to send an email on behalf of the domain (this can help in the battle against spam and spoofed email). They can also be used to verify ownership of the domain name when signing up for third party services.
Logs are records of events, activities, and system messages generated by various components of the operating system and applications. They are essential for monitoring and troubleshooting system behavior.
Linux systems use a variety of log files located in the /var/log directory to store different types of information.
Common log files include:
- OS logs:
- syslog: General system messages.
- auth.log or secure: Authentication and security-related events.
- kern.log: Kernel-related messages.
- messages: Miscellaneous system messages.
- App logs
- apache2/error.log: Apache web server error log.
- mysql/error.log: MySQL database server error log.
logrotate - manages a mass of logs. (create new files, archive old ones, delete them after some time)
/etc/logrotate.d
(session with Brian)
(session with Derrick)
QEMU (short form for Quick Emulator) is an open source hypervisor that emulates a physical computer.
Proxmox Virtual Environment is a complete, open-source server management platform for enterprise virtualization. It tightly integrates the KVM hypervisor and Linux Containers (LXC), software-defined storage and networking functionality, on a single platform.