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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Francesco Tagliani <fran.tm213@gmail.com>
cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17776: Connections are terminated unexpectedly sometimes
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References: <17776-36d858c9afa20043@postgresql.org>
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Comments: In-reply-to Francesco Tagliani <fran.tm213@gmail.com>
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Francesco Tagliani <fran.tm213@gmail.com> writes:
> I found some logs I don't understand.

> ```
> 2023-02-05 00:37:16.858 UTC [1739876] [unknown]@[unknown] FATAL:
>  unsupported frontend protocol 65363.19778: server supports 3.0 to 3.0
> 2023-02-06 12:26:48.844 UTC [467480] [unknown]@[unknown] FATAL:
>  unsupported frontend protocol 16.0: server supports 3.0 to 3.0
> 2023-02-06 02:17:08.205 UTC [257863] [unknown]@[unknown] FATAL:
>  unsupported frontend protocol 65363.19778: server supports 3.0 to 3.0
> 2023-02-06 06:37:00.411 UTC [345467] [unknown]@[unknown] FATAL:
>  unsupported frontend protocol 0.0: server supports 3.0 to 3.0
> 2023-02-06 06:37:00.679 UTC [345468] [unknown]@[unknown] FATAL:
>  unsupported frontend protocol 255.255: server supports 3.0 to 3.0
> ```

Something port-scanning your server, perhaps?  None of those
protocol numbers match anything that Postgres-related code
would use.

			regards, tom lane