Default Credential Access
Default Wisp
Two Meridian Home devices answer on telnet from the open internet. Neither one has ever needed to — the port exists because the reference firmware shipped with it enabled, and nobody who deploys these devices thought to close it. Behind that port sits a factory username and password, identical on every unit of the model, from a real published list the 2016 Mirai botnet carried and tried against the whole internet in turn.
Try: nmap -p 23 203.0.113.0/24