TCP Fast Open (TFO) Support

[Exocomp]

Does pfSense support TCP Fast Open? Basically it is a performance optimization to TCP to save a round trip (initial 3 way hand shake).

More info here: https://tools.ietf.org/html/rfc7413

I would be using it for a case where I setup a port forward, traffic going to pfSense and then pfSense sending the traffic node behind pfSense. So both incoming and outgoing connections are at play.

[stephenw10]

In a port forward the TCP session is not terminated in pfSense so it would not have to support it explicitly. The only issue I could see there would be pf rejecting the TCP state if the packets are flagged incorrectly. However it doesn't appear that they are so I imagine it might just work with no changes. If it does see that traffic as out of state for TCP you can add firewall rules to pass it anyway. As shown here but obviously a different cause:
https://docs.netgate.com/pfsense/en/latest/firewall/troubleshooting-blocked-log-entries-due-to-asymmetric-routing.html?highlight=sloppy#manual-fix

Steve

[marnog]

still not implement TFO in pfsense ?

Many apps now use TFO

thank you

Kin d Regards

[stephenw10]

Nothing has changed in 5 years there. TCP connections are still not terminated in the router/firewall so the TCP session, and therefore what has to support TFO, is between the client and server.
pfSense still doesn't need to support this.

[marnog]

@stephenw10

Thank you for the quick response.

Now many applicantions need TFO

will be good time to put TFO in working orders.
to now get the security risk. I think in Gob area and Datacenter will be a big issue of security now.

Thank you

Kind Regards

[michmoor]

@marnog
HA proxy supports FastOpen but not sure if this fits into your design. Up to you.