Thank you very much for your reply, Anoop.
I will collect the upstream logs and I will let you know.

Have a great day.
Mauro

> On 22 May 2021, at 03:58, Anoop Alias <anoopalias01@gmail.com> wrote:
>
> The private_ip:5044 is closing the connection before completing the request.
>
> You should check the log in the upstream server for why it is doing this. Perhaps a security module or something that drop connection immediately etc
>
> On Fri, May 21, 2021 at 2:46 PM Mauro Tridici <mauro.tridici@cmcc.it <mailto:mauro.tridici@cmcc.it>> wrote:
>
> Dear Users,
>
> I’m noticing a these error messages in /var/log/nginx/error.log.
>
> 021/05/21 10:57:25 [error] 21145#0: *7 recv() failed (104: Connection reset by peer) while proxying connection, client: public_ip, server: 0.0.0.0:5044 http://0.0.0.0:5044/, upstream: "private_ip:5044", bytes from/to client:321/7709, bytes from/to upstream:7709/321
> 2021/05/21 10:58:07 [error] 21145#0: *9 recv() failed (104: Connection reset by peer) while proxying connection, client: public_ip, server: 0.0.0.0:5044 http://0.0.0.0:5044/, upstream: "private_ip:5044", bytes from/to client:321/7709, bytes from/to upstream:7709/321
> 2021/05/21 10:58:46 [error] 21145#0: *11 recv() failed (104: Connection reset by peer) while proxying connection, client: public_ip, server: 0.0.0.0:5044 http://0.0.0.0:5044/, upstream: "private_ip:5044", bytes from/to client:321/7709, bytes from/to upstream:7709/321
> 2021/05/21 10:59:19 [error] 21145#0: *13 recv() failed (104: Connection reset by peer) while proxying connection, client: public_ip, server: 0.0.0.0:5044 http://0.0.0.0:5044/, upstream: "private_ip:5044", bytes from/to client:321/7709, bytes from/to upstream:7709/321
> 2021/05/21 10:59:57 [error] 21145#0: *15 recv() failed (104: Connection reset by peer) while proxying connection, client: public_ip, server: 0.0.0.0:5044 http://0.0.0.0:5044/, upstream: "private_ip:5044", bytes from/to client:321/7709, bytes from/to upstream:7709/321
> 2021/05/21 11:00:55 [error] 21145#0: *17 recv() failed (104: Connection reset by peer) while proxying connection, client: public_ip, server: 0.0.0.0:5044 http://0.0.0.0:5044/, upstream: "private_ip:5044", bytes from/to client:321/7709, bytes from/to upstream:7709/321
> 2021/05/21 11:01:38 [error] 21145#0: *19 recv() failed (104: Connection reset by peer) while proxying connection, client: public_ip, server: 0.0.0.0:5044 http://0.0.0.0:5044/, upstream: "private_ip:5044", bytes from/to client:321/7709, bytes from/to upstream:7709/321
> 2021/05/21 11:02:33 [error] 21145#0: *21 recv() failed (104: Connection reset by peer) while proxying connection, client: public_ip, server: 0.0.0.0:5044 http://0.0.0.0:5044/, upstream: "private_ip:5044", bytes from/to client:321/7709, bytes from/to upstream:7709/321
> 2021/05/21 11:03:06 [error] 21145#0: *23 recv() failed (104: Connection reset by peer) while proxying connection, client: public_ip, server: 0.0.0.0:5044 http://0.0.0.0:5044/, upstream: "private_ip:5044", bytes from/to client:321/7709, bytes from/to upstream:7709/321
> 2021/05/21 11:03:39 [error] 21145#0: *25 recv() failed (104: Connection reset by peer) while proxying connection, client: public_ip, server: 0.0.0.0:5044 http://0.0.0.0:5044/, upstream: "private_ip:5044", bytes from/to client:321/7709, bytes from/to upstream:7709/321
> 2021/05/21 11:04:33 [error] 21145#0: *27 recv() failed (104: Connection reset by peer) while proxying connection, client: public_ip, server: 0.0.0.0:5044 http://0.0.0.0:5044/, upstream: "private_ip:5044", bytes from/to client:321/7709, bytes from/to upstream:7709/321
>
> Basically, it seems that the error is related to a particular (authorized) IP address.
> This remote FILEBEAT client is sending data to LOGSTASH server via NGINX.
>
> Do you some suggestion to fix this annoying issue?
>
> Thank you in advancee,
> Mauro
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> --
> Anoop P Alias
>
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