Tech | 技術 – All About Fei

2025-03-21

Bypass UBC's Block of DeepSeek

As of 4:40PM on March 20, 2025, DeepSeek's domain (chat.deepseek.com) is no longer accessible on UBC network. The bypass is very simple, but let's begin with 2 statements.

I'm not convinced how DeepSeek is exceptionally dangerous compared to other online services such as Meta, Google, TikTok, WeChat, or ChatGPT.
Countries like China and Iran have taught us that any firewalls, even government-level ones, can be bypassed, with the only exception being if a whitelisting system is used (North Korea).

Anyway, UBC only did one thing to block DeepSeek: DNS pollution.

Whenever you visit a website like google.com, your computer looks up the IP address associated with that website, like looking up your doctor's phone number on a phonebook. What UBC did is removing the entry for deepseek.com on its "phonebook" (DNS server), so that the lookup fails.

Therefore, the solution is simple: do not use the DNS Server provided by UBC! Instead, Cloudflare Public DNS can be used, which is free, does not keep logs, and potentially faster than UBC's DNS.

This page is a pretty good guide: https://support.cci.drexel.edu/other-it-resources/generic-web-tips/changing-dns/

For Android, keep in mind that it applies to all networks, and some networks (such as free WiFi at Loblaws stores) block Private DNS. In those cases, you might have to temporarily turn off the Private DNS.

2024-12-282025-01-05

EOSMSG 免費使用方式

檢查後會跳到類似 http://cert.eosmsg.org/canon_dec_ml_eng.php?Data=Q0s9MTEz... (下面省略一長串) 的網頁，將Data=後面的亂碼複製並使用Base64解密（例如此網站），會得到類似以下內容：

CK=xxxx&SN=xxxx&Model=xxxx&Len=xxxx&Firmware=xxxx&SC=AsdCd1NrNUZASdcxYVkRAQS=&MSC=JnNNjNJG77878G8hJBughycXrgtV7nNJKk=&Ver=xxxx&CMOS=xxxx&Time=x

其中SC便是快門數，MSC則是反光鏡數，只是此數字經過很多次的Base64編碼罷了，並沒有加密。分別將SC=和MSC=後的內容分別再進行多次Base64解碼直到變成數字即可。

當然，eosmsg那奇怪模樣的軟件本身是不是病毒就另計了...

2023-11-062023-11-06

Random #5: Make YouTube great again!

My YouTube Home feed has more than 50% of the videos from channels I'm not even subscribed to, while many subscribed channels simply do not appear on my feed.

The shift in recent years in social media from "telling the system what you like" to "system telling you what you like" is troublesome. The fact is we know what we want, and not watching a certain channel for a few weeks doesn't mean we will never want to watch it (that's what the Unlike or Unsubscribe button is for!).

I argue that there are two types of content that one watches: funny, quick, one-off content, and actually interesting, lengthy, in-depth content. Examples of the former includes (and these are directly from my YouTube feed right now) Microsoft Sam Beatbox Duet, 1996 Pontiac Grand Pix Recall: interesting for when you are relaxing, but I basically don't want to see anything like it anymore after watching it. Examples of the latter would be: The Impact of 6GHz on Network Design, PS5 Slim First Look and TEARDOWN!!, or I Visited the Most Depressing Town in Singapore.

Suggesting new content is great to help discover new channels and give visibility to new creators, but there is a limit to it: there is a reason a user decide to subscribe to a channel instead of just watching it and leave, and since the algorithm does not know how the user liked it or not (who cares about the like button anymore??), it is idiotic to suggest this much new content to a user just because the user fell for two clickbaity videos two times in a row.

Going back to the two types of content. Please, only ever suggest a few of the first type, and never the same topic over and over. For the second type, please, prioritize what we literally said we liked, instead of filling my entire feed with train videos (yes I like trains, but I also like many other things that I literally told the algorithm by subscribing).

Thanks for listening. After seeing the 20th Burger King Pokeball recall advertisement parody being suggested just because a few weeks ago I felt bored and watched a few in a row, I decided that I have to write something about this.

2023-02-212024-01-03

Transferring file over high-bandwidth, high-latency link - bbcp

As you might know, I live in Canada while my home server is located in Macau. Both sides have decent internet connection: 150Mbps symmetrical in Macau, 350/100Mbps in Canada. While not crazy fast, this is fast enough for most cases, even for transferring large files. But there is a problem: I can never get this speed...

Speed test from my computer in Canada to my server in Macau via LibreSpeed. Look at that juicy ping and revolutionary upload speed...

The problem

The problem is simple: I can download from my home server somehow close to the limit (150Mbps) but I can only upload at less than 10% of theoretical upload speed, seemingly for no reason.

The investigation

I tried running speedtest from Canada to different hosts in Macau: different ISPs, my server with LibreSpeed, my server with iperf. I found that I only get good speeds when I use multiple connections: multi connection feature on Speedtest.net, iperf with LOTS of parallel streams.

2023-02-022023-03-23

澳門公共天線的前世今生（三）：香港慈雲山的覆蓋範圍

跳出原有的安排，寫個短篇。最近發現了 Radio Mobile 的軟件，原為業餘無線電愛好者的工具，但其電腦版本亦可用作電視發射站的覆蓋範圍分析。由於軟件已經極度過時，操作極為不方便，也不見得是最好的選擇，故不詳細介紹。

在此向 Radio Mobile 開發者 Roger Coude (VE2DBE)、全球地形圖 ALOS World 3D-30m (AW3D30) 提供者日本宇宙航空研究開發機構 (JAXA) 及 OpenStreetMap 貢獻者致謝。

紅色代表信號最好，橙色黃色其次，綠藍等顏色則代表信號非常差。

2022-07-312023-03-23

澳門公共天線的前世今生（二）：曾經使用的頻道來源

上文説到澳門公天公司仍有使用的電視頻道來源，例如是使用魚骨天線接收香港和深圳的信號或是使用衞星天線（衞星獲）接收沒有加密的電視台。不過年紀較大的讀者應該會記得十幾年前電視機是能看到更多的電視台的，而且內容亦更豐富精彩，例如我家人愛看的好萊塢電影台和中天新聞。這些電視台的信號是從何而來？這篇文章將會為你帶來答案。

簡單來説，這些頻道全都是透過衞星傳送，並且是有加密的（上文所述的開鎖衞星台則是沒有加密）。在2012年前，澳門法律並沒有把擅自破解加密的行為視為違法，需由版權方提出投訴後才構成侵權行為。而這些頻道正是「2012年前存在，雖然是破解獲得，但由於版權方沒有投訴因此可以保留」而成的。

2022-06-202023-05-07

澳門公共天線的前世今生（一）：引言、現有頻道來源

小時候一直記得兩件事情：大家都説翡翠台是1台，亞視是2台，但家中的電視的1台卻不是翡翠台；比起香港人，澳門人很幸福，有那麼多的電視台可看，而香港卻只有四台。即使是後來出現了數碼電視，也是澳門人因為公天公司比香港更快人人看到數碼電視，不用等待安裝發射站，甚至不用買機頂盒，因為公天公司早已準備好將數碼頻道轉為模擬^相關資訊。這也導致當時我們一直不解81和85台分途廣播時的81, 85是什麼意思。

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翡翠台與高清翡翠台分途廣播的提示。第一次看到這個畫面的時候我是感到非常疑惑的，電視機既沒有顯示81, 85台，高清翡翠台也沒有顯得比較高清，後來才知道我們在看的是公天公司轉換的模擬信號。連結: https://www.youtube.com/watch?v=ykCAsTsplKw

既然本文是討論澳門的各間公天公司，上面兩件事情的原因也當然就是公天公司了。但爲什麼呢？在看完這系列文章後就會得到解答。

澳門公天公司在成立之初主要是因應香港無綫電視開播，幫助澳門市民接收來自香港的電視信號，以解決每家每戶都需要在大廈天台架設魚骨天線的煩惱，後來同時提供世界各地的電視台。本文正是討論在公天公司提供世界各地電視台，到達公共天線的服務質素的頂峰時，以及遇到來自澳門有線和各大版權持有人的官司，被迫大減頻道數量後繼續營運至今的各種事情，包括頻道的來源、技術探討、法律問題及本人的看法和對於未來的建議。希望可以將關於這個話題的零散歷史資料整合，補充相關的缺失資訊，方便人們瞭解的同時，也望能吸引到有相關資訊人士參加討論，讓各位澳門人更多瞭解澳門公天公司的更多事情。

2022-02-032023-03-23

This is why I prefer Linux

If you do not know yet, the Japanese standard computer keyboard has quite a few more keys than US/other European keyboards that we are used to. Whether there is a point doing so or not is a topic for another time (assuming I am knowledgeable enough to have a proper discussion), but one thing I know for sure^[1] is that on Linux you can remap any keys on your keyboard to any other key supported by the system, meaning you could change those keys on the right side of the spacebar that you never use to something you might use! So I did what every reasonable person would do and spent 5 hours last night, from midnight to 5am figuring it out.

And then I can't use the Enter key anymore.