Tech tips – Teza's tech notes

DNS demystified

Posted on September 6, 2021October 15, 2023 by admin

A lot of the time, when you are editing DNS records, there is a confusion between acronyms.
A Record, CNAME, MX, TXT, etc What are all these? Please read on

TOP level domain > .com .net
Second Level domain .co.nz .com.au etc

SOA record Start of Authority record -> it just simply all details about the domain for example, nameservers, name of the admin, TTL etc.

A Record is used to translate the domain name to its IP address.
yourdomain.com points to> 50.63.202.11

NS Record Name Server Record ns1.yourhosting.com ns2.yourhosting.com

PTR record is a reverse of A record. It looks up for name against IP address.

CNAME stands for Canonical name
Suppose you have an existing domain (DomainA) resolving to an IP address. And the you purchased a second domain (DomainB).
You dont want DomainB to resolve to different IP address. You want to point it to the same IP address as domain A.
What you can do is map the second domain (DomainB) to the existing domain (DomainA) so that the resolve to the same IP address as DomainA.
The result is when a user enters any of these domains, it will direct them to the same website (or same IP address).

Throw in a Nerdy side of me, you can remember CNAME like this.
Who is Bruce Wayne > Look up for Batman > and Batman stays at 1007 Mountain Drive, Gotham.

ALIAs is just like CNAME but the difference is you cant have CNAME for naked domain names, for example mydomain.com
It has to be either A record or an ALIAS.
ALIASes are normally used in AWS to point to AWS resources like EC2, S3, load balancers etc.

TTL Time to live, its basically Caching on either the resolving server or on your local system.
The lower the TTL, the faster it resolves. It could take 48 hours to propagate on all the servers throughout the internet.

MX records are mainly used for emails, if you are setting up an email like mymail@mydomain.com, then you are going to use this.

AWS Access Key and Secret Access Key (SIMPLIFIED)

Posted on September 2, 2021September 2, 2021 by admin

There are two ways to access AWS environments.
1) Console Access
2) Programmatic Access

1) Console Access is when you access to AWS portal with your username and password. The GUI interface

2) In Programmatic Access, you are accessing AWS resources using Command lines, Powershell or SDKs.

-> With Programmatic Access, you are accessing using Access Key ID and Secret Access Keys.

Access Key ID and Secret Access Keys are different from your username and password.

When you create your first AWS account, Access Key ID and Secret Access Keys are also created.

It is important to secure or disable them, and not share these Access Key ID and Secret Access Keys otherwise this will give you the root access to your AWS account.

The best practice would be to create a new user and give specific permissions rather than using the root account.

AWS STS Security Token Service is another way to create a temporary, Limited-privileges credentials to IAM users.

To Disable Access Key, navigate to Identity and Access Management (IAM) under Services. > Manage Access Keys.

Disabling this is one way to secure the account, if programmatic access is not required.

Teza

Unprotected Private Key File

Posted on August 26, 2021August 26, 2021 by admin

Warning: Permanently added '192.168.1.1' (RSA) to the list of known hosts.
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@         WARNING: UNPROTECTED PRIVATE KEY FILE!          @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Permissions 0644 for '/path/to/my/key.pem' are too open.
It is required that your private key files are NOT accessible by others.
This private key will be ignored.
bad permissions: ignore key: /path/to/my/key.pem
Permission denied (publickey).

It’s a common error to see when trying to log in to a server via SSH, and it has a relatively easy fix. But before we get to that, let’s get some background on why this error shows up.

Why am I seeing this Error?

What happened is the key you’re trying to use (key.pem in the example above) is too accessible to users on the system.

This is a bad thing because then you’re not the only one able to use the key, which defeats the purpose. Private keys should only be accessible to one user.

For example, if an attacker somehow gains access to any of the accounts on your system, then they’d be able access the key, as opposed to having to get access to your account specifically. This gives them too many opportunities to get to the private key.

How can I fix it?

Like I said earlier, this is an easy fix. Just run:

$ sudo chmod 600 /path/to/my/key.pem

Or if you are running gui, locate the pem file, right click and change the permissions as per below.

That should do the job.

Failed to execute child process “usr/bin/vivaldi” Vivaldi Browser

Posted on August 11, 2021August 26, 2021 by admin

Vivaldi is a great browser, very fast, tons of control, very good for Pravacy and security but at some point, for whatever reason if you are to uninstall Vivaldi and going back to one of the mainstream browsers like Chrome or Firefox, you might encounter errors like below.

This is because you uninstalled Vivaldi and the path is no longer there, however, when you opens a link, it is still looking for Vivaldi.

2 options here, install Vivaldi back or select the alternative browser. update-alternatives x-www-browsers to list the alternatives and select the current choice.

just my side note.

L I N U X – L I N U X – L I N U X ! ! ! New Beginner’s Guide

Posted on April 26, 2021June 25, 2021 by admin

Here is my advise on Windows users if you want to try Linux out for the first time.
This will be a series of videos to help you from Linux total beginner to Power user level.
So If you like my videos and find them interesting, please Like and Subscribe my channel.

Why not! its just one simple click and you will get all my tech notes tutorials for free!

USB drive shrink in size how to fix

Posted on March 17, 2021March 17, 2021 by admin

Recently I have had some USB sticks which volumes shrank.
These are some of the snapshots of how my USB drive looks like.
It is actually supposed to be 16 GB drive, however showing wrong size.
If you have similar issue, read on.

Below is how it shows on My PC.

Below is how it shows on disk management.

Below is a fix to USB drives showing wrong size.

1) Open Command Prompt as an administrator. Once DISKPART is opened, type in below commands colored in RED.
2) diskpart
3) list disk you will see a list of disks currently attached. Its very important you have to make sure you select the right disk.
4) in my case I had to type : select Disk 2
5) clean
6) create partition primary
7) list partition
8) format fs=NTFS (let it complete formatting, it normally takes a few minutes)
Once done, it will show correct disk size of your USB.

Apply for $300 AWS Credit with AWS Proof of Concept Program

Posted on January 19, 2021June 14, 2021 by admin

Yes Amazon is giving away $300 credit with Proof of Concept Program.
Read on below from AWS and see if you are eligible for the application.

Amazon Web Services wants to help your business scale and grow with low cost, easy to use cloud products and services. The AWS Proof of Concept Program provides a $300 credit to small businesses to quickly get started and test AWS against their specific IT and business requirements by subsidizing a proof of concept. More than a million active customers, from Slack to GE, use AWS Cloud solutions to deliver flexibility, scalability, and reliability. Join them and start scaling your business with AWS today.

To qualify, you must have:

A valid AWS account, with up-to-date billing information
(reseller accounts do not qualify)
Not previously received more than $200 of AWS promotional credit
A sufficient business case and proof of concept to test using the credits
No linked accounts
Credits valid for 6 months

Microsoft Azure is coming to NZ

Posted on October 29, 2020June 14, 2021 by admin

We dont know where, we dont know when but Azure is coming to New Zealand. Hopefully Soon Enough.

Continue reading →