Re: [exim] Problem sending to google.com

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.
--
Cheers,
Jeremy