<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hi,<div class=""><br class=""></div><div class="">Given in tcpdump there was no response at all (not even a rejection), my guess is there is a firewall on the OpenWrt host that drops all port 22 packets.</div><div class="">Are firewall rules listed if you go "iptables -vnL" , or in a config file?</div><div class=""><br class=""></div><div class="">Cheers,</div><div class="">Matt</div><div class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Tue 20/10/2020, at 1:50 pm, 许大仙 <<a href="mailto:xuyiwen14@gmail.com" class="">xuyiwen14@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">Hi!<div class="">Sorry to disturb you.<div class="">I meet some problems when I try to connect to Dropbear Server of Openwrt.</div><div class="">So I really need your help.</div><div class=""><br class=""></div><div class=""><span style="color:rgb(67,67,67);font-family:Arial,sans-serif;font-size:14px;background-color:rgb(252,252,254)" class="">Here's the </span><span id="m_7560821113330906170gmail-tran_1_0" style="color:rgb(67,67,67);font-family:Arial,sans-serif;font-size:14px;background-color:rgb(252,252,254)" class="">thing:</span><br class=""></div><div class=""><div class=""><b class="">1. I run <span style="color:rgb(51,51,51);font-family:Arial,sans-serif;font-size:14px;background-color:rgba(255,255,255,0.8)" class="">QEMU with Openwrt(guest) </span><span style="color:rgb(51,51,51);font-family:Arial,sans-serif;font-size:14px;background-color:rgba(255,255,255,0.8)" class="">for emulating an ARM system on ubuntu 18.04(host).</span></b></div></div><div class=""><span id="m_7560821113330906170gmail-tran_0_0" style="color:rgb(67,67,67);font-family:Arial,sans-serif;font-size:14px;background-color:rgb(252,252,254)" class="">Run</span><span style="color:rgb(67,67,67);font-family:Arial,sans-serif;font-size:14px;background-color:rgb(252,252,254)" class=""> </span><span id="m_7560821113330906170gmail-tran_0_1" style="color:rgb(67,67,67);font-family:Arial,sans-serif;font-size:14px;background-color:rgb(252,252,254)" class="">the following</span><span style="color:rgb(67,67,67);font-family:Arial,sans-serif;font-size:14px;background-color:rgb(252,252,254)" class=""> </span><span id="m_7560821113330906170gmail-tran_0_2" style="color:rgb(67,67,67);font-family:Arial,sans-serif;font-size:14px;background-color:rgb(252,252,254)" class="">commands</span><span style="color:rgb(67,67,67);font-family:Arial,sans-serif;font-size:14px;background-color:rgb(252,252,254)" class=""> </span><span id="m_7560821113330906170gmail-tran_0_3" style="color:rgb(67,67,67);font-family:Arial,sans-serif;font-size:14px;background-color:rgb(252,252,254)" class="">on ubuntu 18.04:</span></div><div class=""><pre style="margin-top:0px;margin-bottom:1.4em;padding:0.7em 1em;font-family:Consolas,"Andale Mono WT","Andale Mono","Bitstream Vera Sans Mono","Nimbus Mono L",Monaco,"Courier New",monospace;font-size:14px;direction:ltr;color:rgb(51,51,51);border-radius:2px;overflow:auto;border:1px solid rgb(204,204,204);background:rgba(255,255,255,0.9)" class="">qemu-system-aarch64 -net nic,vlan=0 -net nic,vlan=1 -net user,vlan=1 \<br class="">-m 1024 -smp 2 -cpu cortex-a57 -M virt -nographic \<br class="">-kernel openwrt-19.07.3-armvirt-64-Image-initramfs \<br class="">-drive if=none,file=disk.img,format=raw,id=hd0 \<br class="">-net user,host=10.0.2.10,hostfwd=tcp:127.0.0.1:10021-:22 \<br class=""> -net nic,model=e1000<br class=""></pre></div><div class=""><span style="color:rgb(51,51,51);font-family:Arial,sans-serif;font-size:14px;background-color:rgba(255,255,255,0.8)" class="">Details: </span><a href="https://openwrt.org/docs/guide-user/virtualization/qemu" target="_blank" class="">https://openwrt.org/docs/guide-user/virtualization/qemu</a>.<span style="color:rgb(51,51,51);font-family:Arial,sans-serif;font-size:14px;background-color:rgba(255,255,255,0.8)" class=""><br class=""></span></div><div class=""><br class=""></div><div class=""><b class="">2. But I can not access dropbear of Openwrt through ssh in my host machine——ubuntu 18.04.</b></div></div><div class="">SSH timeout:</div><div class=""><div class=""><div class=""><span id="cid:ii_kghjkzjf7"><image.png></span><br class=""></div></div></div><div class="">Dropbear Service of Openwrt in QEMU:</div><div class=""><div class=""><span id="cid:ii_kghjbzi84"><image.png></span><br class=""></div></div><div class=""><br class=""></div><div class=""><b class="">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.</b></div><div class="">Captured packages:</div><div class=""><div class=""><div class=""><span id="cid:ii_kghjae4r3"><image.png></span><br class=""></div></div></div><div class=""><u class=""><br class=""></u></div><div class=""><i class=""><b class=""><u class="">This is so strange. Could you give me some possible reasons?<br class=""></u></b></i></div><div class=""><i class=""><b class=""><u class="">Under what circumstances will Dropbear not reply to the packet?</u></b></i><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><b class="">Additional Information:</b><br class=""></div><div class="">1. Config of dropbear</div><div class=""><span id="cid:ii_kghjhsv95"><image.png></span><br class=""></div><div class="">2. User Networking of QEMU</div><div class=""><a href="https://wiki.qemu.org/Documentation/Networking" target="_blank" class="">https://wiki.qemu.org/Documentation/Networking</a><br class=""></div><div class=""><div class=""><span id="cid:ii_kghjitnp6"><image.png></span><br class=""></div></div><div class=""><br class=""></div></div>
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