PfSense+ Builtin Netflow exporter and Bidirectional exports

[keyser]

Hi Netgate

I have been working on building my own netflow collector that is adapted very specifically to the pflow(4) based exporter built into pfSense+ in IPFIX mode.
While my collector now runs really well and manages to build some very informative statistics and details, I have one question:

The builtin export only happens at firewall state closure/timeout which is really great and expected!
But every closed state is exported as two unidirectional IPFIX flows which I then have to pair as a “session” in my collector based on metadata. It’s not really difficult because they always have the exact same start/end time (and the same std. 5 flow tuples = src, dest, srcport, dstport and protocol). But when the firewall is busy they might not arrive adjacently (one after the other). That means I have to keep RAW flows for a while to ensure I can pair both flows to a session.

Since IPFIX supports bidirectional flow exports (as one sesssion instead of two flows), is there any chance that can be enabled in pfSense so flow collectors no longer have to pair the flows?