每个人都必须同意 SO_REUSEADDR 吗？
我在 SO_REUSEADDR 上看到的所有讨论都假设它是在已知端口上创建并绑定到 TCP 套接字的同一个程序。
我有两个不同的程序使用相同的端口，我很好奇该机制是如何工作的 - 为了让程序 2 分配端口，程序 1 刚刚关闭，它们是否都必须指定 SO_REUSEADDR 在他们创建套接字之后？
或者对于其中一个人来说就足够了？如果是这样，当套接字徘徊在 TIME_WAIT 状态时，是先获取套接字还是随后尝试打开它？
这是一个 Python 中的小例子，希望能让情况更清楚；
# one.py
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind(("", 5050)) # Assuming 5050 is available
sys.exit(1) # Assuming s enters TIME_WAIT
# two.py
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind(("", 5050))
s.listen()
将 one.py 和 Two.py 视为两个独立的代码库。
one.py 和 Two.py 是否都需要设置 SO_REUSEADDR 套接字选项，以便 Two.py 能够容忍来自 one.py 的挥之不去的 TIME_WAIT 套接字？
谢谢。
All discussion I've seen on SO_REUSEADDR assumes that it's the same program creating and binding to a TCP socket on a known port.
I have two different programs using the same port, and I'm curious about how the mechanism works -- in order for program 2 to allocate a port program 1 has just closed, do they both have to specify SO_REUSEADDR after they create the socket?
Or is it enough for one of them? If so, the one taking the socket first or the one trying to open it afterwards, when it's lingering in TIME_WAIT state?
Here's a small example in Python to hopefully make the case clearer;
# one.py
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind(("", 5050)) # Assuming 5050 is available
sys.exit(1) # Assuming s enters TIME_WAIT
# two.py
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind(("", 5050))
s.listen()
Think of one.py and two.py as two separate codebases.
Does both one.py and two.py need to set the SO_REUSEADDR socket option in order for two.py to tolerate a lingering TIME_WAIT socket from one.py?
Thank you.
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来回答你的问题。我相信在Linux上，您必须在想要重用端口的程序中ONLY指定
SO_REUSEADDR。很简单。然而在 Microsoft Windows 上，情况就不同了。 Microsoft 在 MSDN 上有一个页面< /a> 涵盖 SO_REUSEADDR 和相关功能。To answer your question. I believe that on Linux you have to specify
SO_REUSEADDRONLY in the program that wants to reuse the port. Very simple. On Microsoft Windows however, this is a different story. Microsoft has a page on MSDN that covers SO_REUSEADDR and related features.我认为是的，所有使用相同端口的程序都应该使用
SO_REUSEADDR。因为重用端口的超时是内核的事情。
（但我可能是错的）。
I think that yes, all programs using the same port should use
SO_REUSEADDR.Because the timeout for reusing ports is a kernel thing.
(but I may be wrong).
监听套接字背后的系统调用是
bind()，并且您不能同时绑定到同一地址上的同一端口：操作系统禁止这样做。SO_REUSEADDR告诉程序退出后其他套接字可能会监听。但只要它没有退出，它就是这个端口的专有。The system call behind listening sockets is
bind(), and you cannot bind to the same port on the same address(es) at the same time: the OS forbids that.SO_REUSEADDRtells that other sockets may listen after the program exits. But as long as it has not exited, it is proprietary of this port.您可以通过将 SO_LINGER 套接字选项设置为零来突然终止 TCP 协商流的 TIME_WAIT 状态。
当您允许两种状态（已建立或什么都没有）时，这很好。
You can abruptly terminate the TIME_WAIT state of TCP negotiation flow by setting SO_LINGER socket option to zero.
Good when you allow two states, ESTABLISHED or nothing.