Cannot Connect to Dropbear Server of Openwrt in QEMU

[许大仙]

Hi!
Sorry to disturb you.
I meet some problems when I try to connect  to Dropbear Server of Openwrt.
So I really need your help.

Here's the thing:
*1. I run QEMU with Openwrt(guest) for emulating an ARM system on ubuntu
18.04(host).*
Run the following commands on ubuntu 18.04:

qemu-system-aarch64 -net nic,vlan=0 -net nic,vlan=1 -net user,vlan=1 \
-m 1024 -smp 2 -cpu cortex-a57 -M virt -nographic \
-kernel openwrt-19.07.3-armvirt-64-Image-initramfs \
-drive if=none,file=disk.img,format=raw,id=hd0 \
-net user,host=10.0.2.10,hostfwd=tcp:127.0.0.1:10021-:22 \
 -net nic,model=e1000

Details: https://openwrt.org/docs/guide-user/virtualization/qemu.

*2. But I can not access dropbear of Openwrt through ssh in my host
machine——ubuntu 18.04.*
SSH timeout:
[image: image.png]
Dropbear Service of Openwrt in QEMU:
[image: image.png]

*3. I tried to use tcpdump to capture packages in Openwrt and found that
dropbear did not respond to any data packet received on port 22.*
Captured packages:
[image: image.png]


*This is so strange. Could you give me some possible reasons?*
*Under what circumstances will Dropbear not reply to the packet?*


*Additional Information:*
1. Config of dropbear
[image: image.png]
2.  User Networking of QEMU
https://wiki.qemu.org/Documentation/Networking
[image: image.png]
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