I have tried the command "ssh -D7777 root@127.0.0.1" at the Openwrt device which is to act as a socks server at port 7777 and I get the response "Dropbear v2020.81" and nothing else happens. The same response is output if I enter "ssh -D7777 root@x.y.z.w" where x.y.z.w is the address of a different Openwrt device. On the other hand, I can run Putty with the dynamic tunnel connecting to either Openwrt device - and works perfectly. But the Putty solution means that I run Putty at my PC, while I would like the ssh client to reside to the Operwrt router of my LAN.
Does somebody understand what "Dropbear v2020.81" signifies? Is it jthat the version of ssh in Openwrt does not support the -D parameter? If I omit -D, it goes through the authentication procedure as expected. I do not think it is a firewall problem, as I entered an explicit firewall rule to accept incoming connections at TCP port 7777.