In this video I explain how to perform SSH Tunneling with Local Port forwarding and remote port 
forwarding 


Chapters
0:00 Intro
3:30 Local Port Forwarding Example
11:20 Remote Port Forwarding Example

I need to access something remote that I don’t have access to. 
only expose 1 port securely and access pretty much any service (database etc..)

ssh -L local_port:remote_address:remote_port username@sshserver

I need people to access something local on my machine that they don’t have access to


ssh -R remote_port:local_address:local_port username@sshserver


For Remote Port forwarding the ssh server  config /etc/ssh/sshd_config should have a property GatewayPorts yes




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Hussein

SSH Tunneling - Local & Remote Port Forwarding (by Example)

Light video today discussing my interviewing skills for software engineering positions. I always ask this open ended question and allow the candidate to go free. 

0:00 Background on Interviews
5:00 Interview Question 

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Hussein

I ask this question to every Backend Engineer I interview

Apache Kafka is a distributed stream processing software developed by LinkedIn and written in Scala and Java.  

Chapters 
0:00 Intro 
2:32 Kafka Broker
5:39 Kafka Producer
7:11 Kafka Consumer
8:34 Kafka Partitions
12:50 Queue vs Pub-Sub
16:47 Consumer Group
23:06 ZooKeeper
29:45 Coding Example
1:02:48 Kafka Pros-Cons
1:17:00 Summary

Download slides here 
https://payhip.com/b/Y0Cq
(Members get all slides for all my video courses for free)


In this video I want to focus on the basics of Kafka, talk about how it works give finally spin up a Kafka cluster and write a producer and a consumer. 

Kafka Components
_ producer
_consumer
_topic 
_partition
How Kafka works
Example ( Ride sharing ) 
Spin Kafka cluster 
Write a producer 
Write a consumer
Kafka Applications
Pros and Cons 



Source Code 
https://github.com/hnasr/javascript_playground/tree/master/kafka

Docker commands spin up kafka
//if you ever mess up or you want to start fresh just stop and remove the containers and rerun the command 

docker stop zookeeper kafka
docker rm zookeeper kafka

docker run --name zookeeper  -p 2181:2181 -d zookeeper


docker run -p 9092:9092 --name kafka  -e KAFKA_ZOOKEEPER_CONNECT=husseinmac:2181 -e KAFKA_ADVERTISED_LISTENERS=PLAINTEXT://husseinmac:9092 -e KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR=1 -d confluentinc/cp-kafka 

Get my fundamentals of database engineering course link redirects to udemy with coupon applied (https://database.husseinnasser.com)

Resources
 KIP 500 (Remove Zookeeper)
https://cwiki.apache.org/confluence/display/KAFKA/KIP-500%3A+Replace+ZooKeeper+with+a+Self-Managed+Metadata+Quorum
 
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Gears and tools used on the Channel (affiliates)

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Stay Awesome,
Hussein

Apache Kafka Crash Course

Netflix is a very popular video streaming website. In today’s episode we devtool this website, look at the requests, protocols and architecture used to stream this content. I like the way the Netflix’s backend empower a great frontend. Enjoy

0:00 Netflix Main Page
6:00 Content Preview and The Netflix Router
15:00 Netflix Video Player and Thumbnails


CreateObjectURL and RevokeObjectURL (Explained by Example)
https://www.youtube.com/watch?v=18q6-QR_XXY&t=4s

DevTool them all Playlist
https://www.youtube.com/playlist?list=PLQnljOFTspQX9U79P6eD_V9USIUTE9yAD


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Fundamentals of Database Engineering udemy course (link redirects to udemy with coupon)
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Introduction to NGINX  (link redirects to udemy with coupon)
https://nginx.husseinnasser.com

Python on the Backend (link redirects to udemy with coupon)
https://nginx.husseinnasser.com

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🎙️Listen to the Backend Engineering Podcast
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Gears and tools used on the Channel (affiliates)

🖼️ Slides and Thumbnail Design 
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Stay Awesome,
Hussein

I like this Backend

In this video we will explain how you can author a web application, host it on your laptop then expose it through the internet via port forwarding. We will explain the difference between private ip in Local Area network and Public IP, we will explain how routers have two IP addresses public and private IP. 

We will also do a live edit on my router configuration to do a port forwarding of port 8080 to my local laptop and even access that through my phone. 

-Hussein



Stay Awesome!
Hussein

Public IP vs. Private IP and Port Forwarding (Explained by Example)

TLS which stands for transport layer security is a protocol for securing communication between client and server. Specifically for HTTPS. Thats what the S is stands for. 

In this video, we will learnq how insecure vanilla HTTP works, HTTPS, then we will learn how HTTPS is possible via the transport layer security and finally we will talk about the improvements in 1.3 that was published August 2018. 


Chapters
0:00 Intro 
1:30 Vanilla HTTP
5:00 HTTPS
8:35 TLS 1.2
14:30 Diffie–Hellman
17:55 TLS 1.3


Vanilla HTTP
HTTPS 
TLS 1.2 handshake
TLS 1.3 enhancements
 

Vanilla HTTP 
Before we discuss TLS, HTTPS or anything else lets go through how HTTP request work. You can type in the browser www.husseinnasser.com , the OSI magic kicks in, client figures out the IP address of husseinnasser.com by calling the DNS which uses UDP. Then HTTP application layer makes a GET / request passes in the IP address and port 80 (default for insecure http). This creates an underlying TCP connection. GET / string among other stuff into the packet and send it over. TCP does its thing server receives GET / calls the appropriate process at the backend which could be just return index.html sets content type text/html and sends back big response for client. All of this obviously is plain text no encryption any kind and if you watched the OSI video we made you can tell that people can sniff/snoop packets and get packets they aren’t supposed to get


HTTPS
Works by negotiating a symmetric key so they can both secure messages. Watch the video we did on encryption. Before we jump to GET request there must be a handshake 🤝 that must occur between the client and server. The tricky part is exchanging that key. Same thing as above except port is 443 instead of 80. Remember once we lose the TCP connection we will have to renegotiate the key. But beauty of this is HTTP is stateless so it remains working just fine. 


Tls handshake 🤝 
The original TLS handshake involves 4 roundtrips. A client hello which the client includes which encryption algorithms it supports (Both symmteric and asymmetric). The server receives the request then replies back with the server certificate which includes the server public key and also the encryptions that they will change to. The client receives the server hello, generates the premaster key, encrypts it with the server’s public key then send it over. The Server decrypts the message, gets the premaster generates the symmetric key finally tells the client that we are good to go. 


Tls 1.3 
TLS 1.3 involves much shorter and much secure communication using only deffie hellman as key exchange and just two round trips. 


More Resources
https://www.cloudflare.com/learning-resources/tls-1-3/
https://blog.cloudflare.com/rfc-8446-aka-tls-1-3/


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Hussein

Transport Layer Security, TLS 1.2 and 1.3 (Explained by Example)

Get my Fundamentals of Database Engineering udemy course to learn more , link redirects to udemy with coupon applied https://database.husseinnasser.com 

This is a practical video on Database Indexing where I explain what is an index, why do we need it and how it can improve the performance of the queries. Also how (if used incorrectly) it can slow down your queries


intro 0:00 
What is an index 0:30 
Describe Table 2:15 
SELECT [ID] WHERE ID 4:00 
SELECT [NAME] WHERE ID 6:30
SELECT [ID] WHERE [NAME] (No index) 9:20
SELECT [ID] WHERE NAME LIKE 11:12 
CREATE INDEX ON [NAME] 12:00
SELECT [ID] WHERE NAME (Indexed) 12:50
SELECT [1D] WHERE NAME LIKE (Indexed) 14:30 
Summary 16:00 

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Hussein

Database Indexing Explained (with PostgreSQL)

If you ever wondered the difference between stateless and stateful applications, REST, horizontal scaling versus vertical scaling? We tackle those in a small example. Hope you guys enjoy this quick video. We explain the advantages and disadvantages of each application. 


0:00 Intro
1:14 Stateful Application
8:40 Stateless Application 

Online diagram tool used in this video: Http://www.gliffy.com 

Checkout the rest of the content for more software engineering topics by example. 

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Stay Awesome
-Hussein Nasser
www.husseinnasser.com