Re: login -h

[rhaas () cygnus arc nasa gov (Robert M. Haas)]

> I don't think anyone should rely on wtmp for any kind of security.
> Whatof rsh?  Its easy enough to do a rsh <host> xterm -ut -display <foo>
> and avoid wtmp detection.  The -ut flag tells xterm to not make a 
> entry in utmp and it never considers making a wtmp entry.  I suppose
> because it never has permissions to.  The rsh server would have to
> make the wtmp entry.  Which is odd it doesn't because it does if
> envoke a shell with it.  Hmmmm...

rsh does not make a wtmp entry; rlogin does. rsh is a flat link; i.e. you
can't do IOCTL's on the client end and have them propagated across the
link or whatever, it's just a socket connection. rlogin on the other hand
emulates things like IOCTLs and so forth; since you are really "logging
in" to the machine and not just executing a single command, it makes a
wtmp entry.

If given a hostname to connect to, but no specific command to execute,
rsh invokes rlogin. Thus a wtmp entry is created. ...Robert