Understanding socket and port in TCP

Issue #287 When digging into the world of TCP, I get many terminologies I don’t know any misconceptions. But with the help of those geeks on SO, the problems were demystified. Now it’s time to sum up and share with others :D What defines a unique connection ? There are 5 elements that identify a connection. They call them 5-tuple Protocol. This is often omitted as it is understood that we are talking about TCP, which leaves 4....

May 25, 2019 · 4 min · 774 words · Khoa

How to deal with CSS responsiveness in Wordpress

Issue #283 Original post https://medium.com/fantageek/dealing-with-css-responsiveness-in-wordpress-5ad24b088b8b During the alpha test of LearnTalks, some of my friends reported that the screen is completely blank in search page, and this happened in mobile only. This article is how I identify the problem and found a workaround for the issue, it may not be the solution, but at least the screen does not appear blank anymore. As someone who likes to keep up with tech via watching conference videos, I thought it might be a good idea to collect all of these to better search and explore later....

May 23, 2019 · 3 min · 472 words · Khoa

How to use One Dark theme and Fira Code font for IDEs

Issue #281 A good theme and font can increase your development happiness a lot. Ever since using Atom, I liked its One Dark theme. The background and text colors are just elegant and pleasant to the eyes. One Dark Original designed for Atom, one-dark-ui that claims to adapt to most syntax themes, used together with Fira Mono font from mozilla. There is also Dracula which is popular, but the contrast seem too high for my eyes....

May 23, 2019 · 2 min · 346 words · Khoa

20 recommended utility apps for macOS

Issue #274 Original post https://hackernoon.com/20-recommended-utility-apps-for-macos-in-2018-ea494b4db72b Depending on the need, we have different apps on the mac. As someone who worked mostly with development, below are my indispensable apps. They are like suits to Tony Stark. Since I love open source apps, they have higher priority in the list. Open source apps iTerm 2 https://www.iterm2.com/ iTerm2 is a replacement for Terminal and the successor to iTerm. It works on Macs with macOS 10....

May 23, 2019 · 6 min · 1174 words · Khoa

Introducing Learn Talks — Awesome conference and meetup talks

Issue #269 Original post https://medium.com/swlh/introducing-learn-talks-awesome-conference-and-meetup-talks-e97c8cf7e0f Product Hunt https://www.producthunt.com/posts/learn-talks Hi, it’s Khoa here. I’m so glad to finally launch LearnTalks, in order to help others and myself to catch up with new conference and meetup talks. Being one who is extremely passionate about making things and writing , I also love to learn about every new thing in tech. Tech moves so fast, what we learn today may be deprecated very soon, and only continuous learning can keep us move forward....

May 23, 2019 · 2 min · 362 words · Khoa

Jitter buffer in VoIP

Issue #157 This post was from long time ago when I did pjsip A jitter buffer temporarily stores arriving packets in order to minimize delay variations. If packets arrive too late then they are discarded. A jitter buffer may be mis-configured and be either too large or too small. Impact If a jitter buffer is too small then an excessive number of packets may be discarded, which can lead to call quality degradation....

February 27, 2018 · 2 min · 258 words · Khoa

How to calculate packet size in VoIP

Issue #155 As you have probably observed in your studies, there is a determined method for calculating VoIP packet sizes. The packet size depends on many different variables, so there is no great answer for an “average” packet size – average depends on the environment. Just as an example, if you currently have VoIP running within a LAN and want to provision a new WAN so you can use VoIP to another site, knowing how big your VoIP packets are on the LAN won’t help....

February 27, 2018 · 3 min · 500 words · Khoa

Netcut and ARP

Issue #153 Bad people can use Netcut to limit other ’s internet access in same network How does Netcut work Netcut uses attacking technique called ARP Spoofing. ARP (Address Resolution Protocol) is a link layer procotol, it is used for resolving network layer address (IP) into link layer address (MAC). When we want to send IP packet to another host (a computer in the same LAN, or the Gateway), we must know the destination IP address....

February 27, 2018 · 3 min · 559 words · Khoa

Learning sine

Issue #146 To be written … Old math equations become useful today 😍 v = 1 - x From https://www.desmos.com/calculator

January 26, 2018 · 1 min · 20 words · Khoa

Case sensitivity in HTTP

Issue #115 Is URL case sensitive ? According to HTML and URLs URLs in general are case-sensitive (with the exception of machine names). There may be URLs, or parts of URLs, where case doesn’t matter, but identifying these may not be easy. Users should always consider that URLs are case-sensitive. Is header case sensitive? According to RFC 7230 Each header field consists of a case-insensitive field name followed by a colon (":"), optional leading whitespace, the field value, and optional trailing whitespace....

December 6, 2017 · 1 min · 152 words · Khoa

Using assembly

Issue #112 I’m very fascinated when people use assembly to perform investigation, that’s just mind blowing 💥 . Here are some of the favorite use cases Why blank Gets You Root

November 30, 2017 · 1 min · 31 words · Khoa

Please reconsidering your choice of libraries

Issue #105 Are you willing to take vaccines you don’t know about? I like open source. I ’ve made some and contributed to some. I also use other people ’s open source libraries and learn a lot from them 😇 Open source can help us build better, faster and maybe more performant software by basing on other people ’s hard work. We can also collaborate and make it better. But it’s also a double edges sword if you’re not judging carefully....

November 10, 2017 · 3 min · 620 words · Khoa

Fixing login hanging in macOS High Sierra

Issue #86 Today I met a strange problem. After I enter my password, the progress bar runs to the end, and it is stuck there forever. No matter how many times I try to restart. I finally need to go to Recovery mode by pressing Cmd+R at start up. I then select Get Help Online to open Safari. Strangely enough I wasn’t connected to Internet After select the wifi icon on the status bar to connect internet, I then restart and can login again....

October 16, 2017 · 1 min · 97 words · Khoa

Dear SDK developers

Issue #84 Dear SDK developers, Please don’t do swizzling. Give us instructions on where to call your APIs instead of doing unnecessary swizzling. You’re making it for developers to use, and they know how to write code. Most of the time, you don’t know how to do swizzling right ⚠️ Please don’t use configuration file. If possible, please consider configuration via pure code, instead of the plist file that is more exposable in the app bundle....

October 10, 2017 · 2 min · 315 words · Khoa