How could it be incorrect? rsh was clearly modelled after rlogin, and ssh was clearly modelled after rsh.
The command line options were almost identical for an easy switch. ssh even respected the .rhosts file! Last time I checked, that functionality was still in place.
Both the rlogin-family of commands and the telnet/ftp-family were in use across the Internet, certainly in cases where Kerberos was used. I would think telnet was more common, certainly so outside the UNIX sphere of influence, but things like Kermit also existed.
They all got SSL-encapsulated versions in time, but Kerberos solved authentication for free, and for the simpler use cases ssh had already taken over by then. And in the longer run, simple almost always wins!
Agree that ssh was modeled after rsh. But rsh was a different kind of security problem, which wasn't really relevant on the wider Internet.
ssh solved the "pass credentials in cleartext over untrusted networks" problem. Consequently it replaced telnet and ftp. It also duplicated the functionality of rsh and rcp, so those protocols became irrelevant. But that was not the important goal.
> Kerberos solved authentication for free,
This made me laugh. Kerberos didn't do anything for free. :)
Even in Athena, Kerberos had reliability problems. In the wider world, it was very hard to find a well-managed Kerberos implementation. Things are different now!
The command line options were almost identical for an easy switch. ssh even respected the .rhosts file! Last time I checked, that functionality was still in place.
Both the rlogin-family of commands and the telnet/ftp-family were in use across the Internet, certainly in cases where Kerberos was used. I would think telnet was more common, certainly so outside the UNIX sphere of influence, but things like Kermit also existed.
They all got SSL-encapsulated versions in time, but Kerberos solved authentication for free, and for the simpler use cases ssh had already taken over by then. And in the longer run, simple almost always wins!