this is a problem that I already had (and never could solve) with QNX 6.4.1, now I tried again with QNX 6.5 but still don't get it working. I start qemu with
qemu-system-x86_64 -hda qnx.img -m 512 -net nic -net user
(brain-attritional simple and well-working with all other operating systems). QNX comes up without problems and it detects the network card successfully.
But with that network interface nearly nothing is possible: DHCP does not work, assigning a fixed IP 10.0.2.15 / netmask 255.255.255.0 works but I can't reach anybody outside of this qemu-envorinment. The default gateway is set to 10.0.2.2.
Within the QNX-forum nobody could help, so may be here somebody has some hints what I could try?