$ x86_64-softmmu/qemu-system-x86_64 -monitor tcp:localhost:6000
x86_64-softmmu/qemu-system-x86_64: -monitor tcp:localhost:6000: Failed to connect to socket: Connection refused
chardev: opening backend "socket" failed
$ x86_64-softmmu/qemu-system-x86_64 -monitor tcp:foo.bar:12345
qemu-system-x86_64: -monitor tcp:foo.bar:12345: address resolution failed for foo.bar:12345: Name or service not known
chardev: opening backend "socket" failed