tramp-restricted-shell-hosts-alist

tramp-restricted-shell-hosts-alist is a variable defined in `tramp.el'.
Its value is

nil

Documentation:
List of hosts, which run a restricted shell.
This is a list of regular expressions, which denote hosts running
a registered shell like "rbash". Those hosts can be used as
proxies only, see `tramp-default-proxies-alist'. If the local
host runs a registered shell, it shall be added to this list, too.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.3 of Emacs.