Networking SunOS 4.1 guest with Windows 11 host

[Michele Denber]

    I'm running QEMU 7.2 on a Windows 11 host, up to date with all
    updates:
    
    C:\Program
      Files\qemu>qemu-system-sparc --version
      QEMU emulator version 7.2.0 (v7.2.0-11948-ge6523b71fc-dirty)
      Copyright (c) 2003-2022 Fabrice Bellard and the QEMU Project
      developers
    
    I want to run a SunOS 4.1.4 guest with networking.  I start it like
    this:
    
      C:\Program Files\qemu>qemu-system-sparc -machine
        SS-5 -m 64 -drive file=sunos-hdd.img,bus=0,unit=3,media=disk
        -device
        scsi-cd,channel=0,scsi-id=6,id=cdrom,drive=cdrom,physical_block_size=512
        -drive if=none,file=Solaris1.1.2SPARC.iso,media=cdrom,id=cdrom
        -vga cg3 
        -net nic,model=lance
        -net tap,ifname=tap0,script=no,downscript=no
    
    I was able to boot from the iso and install SunOS on the .img disk,
    but I am unable to see my 192.168.0.x LAN from the guest.   ping
    192.168.0.1 (the router) fails.  The host firewall is turned off.
    
    The QEMU console shows this:

    The Windows host Network Connections pane shows this:

    The SunOS guest shows this:

    but I have no connectivity to the LAN.  There are many many examples
    on the web of how to do this, but they all use deprecated features
    or just don't work at all (for me).  One thing I've not been able to
    find is how to configure the tap interface on the PC.  Should it be
    bridged or not?  Should I set a static IP and gateway there or not?
    
    Any help on sorting this out would be most appreciated.
    
                - Michele