$ make bin-x86_64-linux/gpxe.linux

$ ./bin-x86_64-linux/gpxe.linux --net tap,if=tap3,mac=52:54:00:12:34:56 --net tap,if=tap4,mac=52:54:00:12:34:57 # etc

• Linux config:

  CONFIG_BRIDGE=y
  CONFIG_TUN=y

• tunctl tool
• brctl tool

Assuming eth0 is the primary network interface used for networking.

• Disable current networking
• Add a bridge

  # brctl addbr br0

• Add eth0 to the bridge

  # brctl addif br0 eth0

• Start networking on br0

  # dhclient br0

At this point networking should be working as normal.

• Create a tap device

  # tunctl -u $USER -t tap1 # -u so that we don't need root to access the device

• Enable it

  # ifconfig tap1 up

• Add it to the bridge

  # brctl addif br0 tap1

At this point the tap1 interface should be usable in gPXE usermode. Multiple interfaces can be added like that.