[Beowulf] are compute nodes always kept in a private I/P and switch space?

[Rahul Nabar]

I always took it as natural to keep all compute nodes on a private
switch and assigned them local I/P addresses. This was almost
axiomatic for an HPC application in my mind. This way I can channel
all traffic to the world and logins while a select login-node. Then
firewall the login nodes carefully.

Just today, though, on a new project the  admin said he always keeps
his compute nodes with public I/Ps and runs individual firewalls on
them.

This seemed just so wrong to me in so many ways but i was curious if
there are legitimate reasons why people might do this? Just curious.

-- 
Rahul