Hi raoufkh, did you figure out how to specify N9 interfaces vs N3? I have the same question; I’ve figured out the slightly different panic I get in On latest v3.05, PDU session fails with 'has no pre-config route', referred to previous similar post, no luck - #2 by ryanwwest is because in upf.go UPF.GetInterface(), it doesn’t find any N9 interfaces so it returns nil here: smf/upf.go at eb13ffabeef1f0ca281f62113d1fde2dbaac853a · free5gc/smf · GitHub.
And that nil being returned causes the nil dereference panic here: github (dot) com/free5gc/smf/blob/eb13ffabeef1f0ca281f62113d1fde2dbaac853a/context/datapath.go#L393
(kind of similar to the panic you solved with IPV4IPV6 code changes)