EXTERNAL: OSError: [Errno 48] Address already in use

Jim Lee jlee54 at gmail.com
Sat Jun 30 14:51:36 EDT 2018



On 06/28/18 18:04, Dan Stromberg wrote:
> [snip]
> Start an echo server process P that listens on tcp/5555.
>
> Initiate a connection from a client machine to process P at tcp/5555. It
> works as expected.
>
> Kill P.
>
> Initiate a connection from a client machine to process P at tcp/5555.  It
> gives a connection refused as expected.
>
> If someone else comes along soon after and starts a different echo server
> process Q at tcp/5555 on the same server, it starts up immediately if P
> used SO_REUSEADDR.
>
> Then initiate a connection from the same (or different) client machine to
> process P (which no longer exists).  Q gets the data intended for P.
>
>

There are all sorts of theoretical vulnerabilities that simply don't 
manifest in real life.  I think this is one of them.

Me: "It hurts when I do this."  Doctor: "Well, don't do that."

-Jim




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