tssh

trzsz-ssh ( tssh ) is an ssh client designed as a drop-in replacement for the openssh client. It aims to provide complete compatibility with openssh, mirroring all its features, while also offering additional useful features. Such as login prompt, batch login, remember password, automated interaction, trzsz, zmodem(rz/sz), udp mode like mosh, etc.

tsshd is a UDP-based SSH server built for unreliable networks. It supports seamless roaming across networks and IP changes, and works well on high-latency links such as cellular connections and unstable Wi-Fi.

(tssh from trzsz)+(CA key with embed-encrypt)+(sshd from gliderlabs)+(access over NAT using jumphost ssh-j.com)+(ser2net with putty or direct connect to serial console or over browser)