Jeremy is correct... It is a qemu limitation (that is well known with a little google search).
It's possible to modify qemu to support more as mentioned in the following post: post6979.html#p6979
And the file in question can be seen in full in the Qemu Github mirror: https://github.com/qemu/qemu/blob/maste ... net.h#L163
From a GNS3 point of view, I feel it's most sensible to stick with what Qemu has as it's default (otherwise we're going to run into problems with people not running a modified version).
The QEMU version (0.11.0) that comes packaged with the All-In-One GN3 0.8.7 seems to limit the number of adapters to 8 but the QEMU (2.1.0) bundled with the beta works fine if you point the 0.8.7 GUI to use the beta 4 version.
I used a standalone install of QEMU on Windows 7,was able to use the qemuwrapper and qemu-img that were bundled with GNS3 but changed the executable path to the standalone Qemu.
So just to be clear: GNS3 0.8.7 gui, qemuwrapper.ex, and qemu-img.exe was used with the QEMU (2.15.0) binary installed as a standalone.
The results were that I was able to bump the NICs up to 16 in the QEMU config for Tinycore connect it to a hub, put a router on the other side, and ping back and forth with eth15. I didn't check every adapter available and I can't account for stability because I don't have a use for 16 ports on one guest yet.
So current limitation is a matter of the GUI's hard limit of 8 adapters max.
thanks buddy for sharing your trick .would you pls tell from where u get QEMU (2.15.0) binary installer for windows .as on gns3 portal i search but not get i also search on qemu there also its not available.please help me to get it share your QEMU (2.15.0) binary installer with us....