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 -- ## List details at https://lists.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
