Re: [exim] syscall: Connection reset by peer (outlook.com)

On 27/02/2021 20:38, MRob via Exim-users wrote:
> Hello,
> I'm getting lots of these in exim log:
> 2021-02-25 04:31:15.790 [19189] SSL_write: (from mail-pu1apc01hn2214.outbound.protection.outlook.com (APC01-PU1-
> obe.outbound.protection.outlook.com) [52.100.183.214]:42879) syscall: Connection reset by peer
>
> Only a couple are not from outlook.com, so mostly a problem with outlook.com servers? I am not sure if they find something they don't like about my TLS and decide to disconnect?
>
> I also get plenty of successful mail from outlook.com so its confusing. But some remote sender using microsoft reported getting mail returned due to expired retries/unable to connect.
>
> Can anyone help to understand this more?
>

This sounds possibly like the cause of commits afaf5a50b0, f1e494e002
since 4.94. The description of the new log_selector "protocol_detail" :

+Currrently the only effect is to enable logging, under TLS,
+of a TCP RST received directly after a QUIT (in server mode).
+
+Outlook is consistently doing this; not waiting for the SMTP response
+to its QUIT, not properly closing the TLS session and not properly closing
+the TCP connection. Previously this resulted is an error from SSL_write
+being logged.


Summary: it's noise, you can ignore it. Or you can swear in Seattle's
direction if it helps your sanity.
--
Cheers,
Jeremy