#nixwrt on qemu is sending dhcp and all the gubbins to a second qemu process that I booted using a System-Rescue iso image.

This is probably an achievement. I say "probably" because I can't actually see the output from the system-rescue vm because it doesn't work properly with -serial stdio. But the packets are flowing ...

Nov 21 17:56:45 dnsmasq-dhcp[120]: 13935373 client MAC address: 52:54:00:12:34:56

Nov 21 17:56:45 dnsmasq-dhcp[120]: 13935373 client provides name: sysrescue

Nov 21 17:56:45 dnsmasq-dhcp[120]: 13935373 DHCPSOLICIT(eth1) 00:04:dc:c5:43:08:80:09:95:31:b5:c5:75:68:d8:5f:2e:2e

Nov 21 17:56:45 dnsmasq-dhcp[120]: 13935373 DHCPREPLY(eth1) 2001:8b0:de3a:40dc::f0dc

00:04:dc:c5:43:08:80:09:95:31:b5:c5:75:68:d8:5f:2e:2e sysrescue