How to properly install rsh without compromising system security

[o.greve at axis.nl (Olaf Greve)]

Hi,

For a project at work we are currently installing a distributed software 
development platform which has been developed years ago. All swell, of 
course, but the issue is that it depends on rsh for remote application 
invocation.

Now... I have always been taught that rsh, rlogin and rexec are BAD and 
that one should really stick to SSH only.

Unfortunately, I do not have enough time to completely patch over the 
platform such that it will use SSH (and frankly, that's really a task 
the official developers should perform!), so, I'd like to temporarily 
enable rsh.

Now, I did some quick RTFM-ing and checking in Google, and it looks like 
this is provided by xinetd.

 From Gnome's services menu I have enabled rsh (and hence xinetd), but I 
do not yet seem to be able to remotely perform something like "rsh 
<machine name> ls". It just says "permission denied". Good. No problem. 
In fact, this is probably good. ;)

So, to proceed with this the proper way, can anyone tell me how I can 
properly configure rsh such that I do not compromise system security too 
much (note: I am behind a firewall and my machine is not accessible in 
any way from the outside world, so there is not all too much concern in 
opening up rsh, even with root access)?

Also, on a more general note: I'm not familiar yet with proper PAM 
concepts and configuration. Does anyone know a good (and preferrably not 
all too long) reference guide with which I can quickly and properly 
familiarise myself with the concepts and the proper way of configuring it?

Tnx in advance, and cheers!
Olafo