The Backend Engineering Show with Hussein Nasser

DST Root CA X3 Expires on September 2021, a ROOT certificate that signs Let's Encrypt Certificate authority, a very popular CA. In this video, I will discuss the ramification of this change. Support my work on PayPal https://bit.ly/33ENps4 Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join 🧑‍🏫 Courses I Teach https://husseinnasser.com/courses 🏭 Backend Engineering Videos in Order https://backend.husseinnasser.com

Salesforce services went down as a result of a DNS update, let us discuss how can tiny DNS unavailability cause a severe outage of 5 hours. From salesforce "On May 11, 2021, at approximately 21:08 Universal Coordinated Time (UTC), the Salesforce Technology team became aware of a service disruption across Salesforce production instances. The disruption impacted the ability for users to log into their Salesforce environments within the core Salesforce services, Marketing Cloud, Commerce Cloud, Government Cloud, Experience Cloud, Heroku, Pardot, and Vlocity. In addition, the status.salesforce.com Trust site was also unavailable, and customers were unable to log support cases. Some customers may have also experienced issues with Multi-Factor Authentication (MFA) during the incident. " Resources https://help.salesforce.com/articleView?id=000358392&type=1&mode=1 Support my work on PayPal https://bit.ly/33ENps4 Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join 🧑‍🏫 Courses I Teach https://husseinnasser.com/courses 🏭 Backend Engineering Videos in Order https://backend.husseinnasser.com

In this show, I go into detail on how HAProxy achieved 2 million HTTP requests per second. This is a very well-written article that discusses how the HAProxy team benchmarked the product on a 64 core ARM machine leading to over 2 million requests per second. There are many components and low-level points that I try to elaborate on, timestamps below.  0:00 Intro  2:40 Summary of the Article  11:55 Latency and Throughput in HAProxy 2.3 vs 2.4  21:00 How TCP Connections Affects Performance  28:00 Maximum Packets we can get in 100Gbps Network?  35:00 How 64 Cores are divided between workloads  40:00 Tail latencies HAProxy 2.3 vs 2.4  42:50 How TLS Affects Performance?  HAProxy Blog https://www.haproxy.com/blog/haproxy-forwards-over-2-million-http-requests-per-second-on-a-single-aws-arm-instance/ Support my work on PayPal https://bit.ly/33ENps4 Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join 🧑‍🏫 Courses I Teach https://husseinnasser.com/courses

In this show, I discuss why we have 3 data models in database systems, OLTP (Online Transactional Processing) OLAP (Online Analytical Processing), and HTAP (Hybrid Transactional Analytical Processing). I’ll also explain the difference between them, the use of ETL tools (extract transform load) to load data from transactional to analytical databases, and what is the future of HTAP. Support my work on PayPal https://bit.ly/33ENps4 Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join 🧑‍🏫 Courses I Teach https://husseinnasser.com/courses

Watch this if you are using IP Address validation in both NodeJS and Python, these two libraries strip leading zeros which can lead to server side request forgery. Let us discuss Resources https://www.bleepingcomputer.com/news/security/critical-netmask-networking-bug-impacts-thousands-of-applications/ https://www.bleepingcomputer.com/news/security/python-also-impacted-by-critical-ip-address-validation-vulnerability/ Support my work on PayPal https://bit.ly/33ENps4 Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join 🧑‍🏫 Courses I Teach https://husseinnasser.com/courses

In this video, I’ll discuss the Pingback attack, a new clever attack that uses both DLL files through Oracle Component Interface (OCI.dll) and ICMP protocol to deliver commands between the victim machines and the command center.  Resources  https://thehackernews.com/2021/05/new-pingback-malware-using-icmp.html  https://en.wikipedia.org/wiki/Internet_Control_Message_Protocol  https://en.wikipedia.org/wiki/Oracle_Call_Interface Support my work on PayPal https://bit.ly/33ENps4 Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join 🧑‍🏫 Courses I Teach https://husseinnasser.com/courses

In this podcast I’ll explain the message queues, the request response pattern and the publish subscribe pattern. I will also illustrate the main differences between them and when to use over another. 0:00 Intro 0:30 Message Queues in 60 Seconds 1:24 When to Use Message Queues? 14:33 Request Response Pattern 20:00 Request Response Pros & Cons 24:11 Publish Subscribe Pattern in 60 Seconds 25:13 Publish Subscribe Pattern 31:49 Publish Subscribe Pattern Pros and Cons Support my work on PayPal https://bit.ly/33ENps4 Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join 🧑‍🏫 Courses I Teach https://husseinnasser.com/courses

502 Bad Gateway is one of the most infamous errors on the backend, it usually means “hey something wrong with your backend server” but it doesn’t really give enough information.  In this video,  I’ll go through details on why proxies and gateways like NGINX and HAProxy should consider throwing more fine detailed HTTP error codes.   502 Bad Gateway The server was acting as a gateway or proxy and received an invalid response from the upstream server.   0:00 intro   3:45 What Causes a 502 Bad Gateway? 8:00 Cloudflare HTTP error codes  13:00 Security Implications Support my work on PayPal https://bit.ly/33ENps4 Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join 🧑‍🏫 Courses I Teach https://husseinnasser.com/courses

In this episode I’ll talk about how VPN works, networking, IPSec and will also discuss the benefits of VPN and what happens when a VPN is hacked?   * Intro 0:00   * How Networking Works? 2:20   * How VPN Works? 10:00   * VPN Benefits 17:50  * What happens when VPN is hacked 20:20 Support my work on PayPal https://bit.ly/33ENps4 Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join 🧑‍🏫 Courses I Teach https://husseinnasser.com/courses

There is an ongoing situation with the Linux kernel community and the University of Minnesota Department of Computer Science & Engineering. We discuss this in this episode and I give my opinion