vue 阻止事件傳入

If all incoming connections to your computer are being blocked, then how can you still receive data and/or have an active connection? Today’s SuperUser Q&A post has the answer to a confused reader’s question.

如果到計算機的所有傳入連線都被阻止，那麼如何仍然可以接收資料和/或保持活動連線？ 今天的“超級使用者問答”帖子回答了一個困惑的讀者的問題。

Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites.

今天的“問答”環節由SuperUser提供，它是Stack Exchange的一個分支，該社群是由社群驅動的Q＆A網站分組。

Screenshot courtesy of Linux Screenshots (Flickr).

螢幕截圖由Linux螢幕截圖(Flickr)提供。

問題 (The Question)

SuperUser reader Kunal Chopra wants to know how his computer can still receive data if all incoming connections have been blocked:

超級使用者閱讀器Kunal Chopra想知道如果所有傳入連線都被阻止，他的計算機仍如何接收資料：

If your ISP or firewall is blocking all incoming connections, how can web servers still send data to your browser? You send the request (outgoing) and the server sends data (incoming). If you block all incoming connections, how can the web server respond?

如果您的ISP或防火牆阻止了所有傳入連線，那麼Web伺服器如何仍將資料傳送到瀏覽器？ 您傳送請求(傳送)，而伺服器傳送資料(傳入)。 如果您阻止所有傳入連線，則Web伺服器如何響應？

What about video streaming and multi-player games where UDP comes into use? UDP is connectionless, so there is no connection to be established, so how does the firewall or ISP handle that?

使用UDP的視訊流和多人遊戲怎麼辦？ UDP是無連線的，因此沒有建立連線，那麼防火牆或ISP如何處理呢？

How is data still able to reach Kunal’s computer if all incoming connections have been blocked?

如果所有傳入連線都被阻止，資料仍如何能夠到達Kunal的計算機？

答案 (The Answer)

SuperUser contributor gowenfawr has the answer for us:

超級使用者貢獻者gowenfawr為我們提供了答案：

“Incoming block” means that incoming new connections are blocked, but established traffic is allowed. So if outbound new connections are allowed, then the incoming half of that exchange is okay.

“傳入阻止”表示阻止傳入的新連線，但允許建立的流量。 因此，如果允許出站新連線，則該交換的傳入一半是可以的。

The firewall manages this by tracking the state of connections (such a firewall is often called a Stateful Firewall). It sees the outgoing TCP/SYN and allows it. It sees an incoming SYN/ACK, verifies that it matches the outbound SYN it saw, lets that through, and so on. If it permits a three-way handshake (i.e. it is allowed by the firewall rules), it will allow that exchange. And when it sees the end of that exchange (FINs or RST), it will take that connection off the list of allowed packets.

防火牆通過跟蹤連線狀態進行管理(這種防火牆通常稱為“狀態防火牆” )。 它看到傳出的TCP / SYN並允許它。 它看到傳入的SYN / ACK，驗證它是否與看到的出站SYN匹配，並使其通過，依此類推。 如果允許三向握手(即防火牆規則允許)，它將允許該交換。 當看到交換結束(FIN或RST)時，它將把該連線從允許的資料包列表中刪除。

UDP is done similarly, although it involves the firewall remembering enough to pretend that UDP has a connection or session (which UDP does not).

UDP的執行方式與此類似，儘管它會使防火牆記住足夠多的內容以假裝UDP具有連線或會話(而UDP沒有)。

Have something to add to the explanation? Sound off in the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.

有什麼補充說明嗎？ 在評論中聽起來不錯。 是否想從其他精通Stack Exchange的使用者那裡獲得更多答案？ 在此處檢視完整的討論執行緒。

翻譯自: https://www.howtogeek.com/212829/if-you-block-all-incoming-connections-how-can-you-still-use-the-internet/

vue 阻止事件傳入