Autor: Victor Sudakov Datum: To: exim-users Betreff: Re: [exim] Problem sending to google.com
Jeremy Harris via Exim-users wrote: > On 28/09/2022 08:40, Victor Sudakov via Exim-users wrote:
> > I wonder what I will lose if I leave net.ipv4.tcp_fastopen=0 on the
> > mail server (not very loaded)?
>
> Not much unless your system also runs a high rate of TCP connections for
> other services (eg. web). The bug (it's in the Linux firewall) might
> be for client connections only; I'm not certain. Fix is in the 5.17 kernel.
> However, all TCP-using services which are coded to try TFO will
> be affected in the same way as SMTP.
Maybe I'd be better off setting hosts_try_fastopen to ":" in Exim only, just in case?
