dired-ls-F-marks-symlinks is a variable defined in `dired.el'.
Its value is

Informs Dired about how `ls -lF' marks symbolic links.
Set this to t if `ls' (or whatever program is specified by
`insert-directory-program') with `-lF' marks the symbolic link
itself with a trailing @ (usually the case under Ultrix).

Example: if `ln -s foo bar; ls -F bar' gives `bar -> foo', set it to
nil (the default), if it gives `bar@ -> foo', set it to t.

Dired checks if there is really a @ appended. Thus, if you have a
marking `ls' program on one host and a non-marking on another host, and
don't care about symbolic links which really end in a @, you can
always set this variable to t.

You can customize this variable.