On Thu, Jan 22, 2015 at 1:08 AM, Cameron Seay <[email protected]> wrote:

> I am teaching several nainframe classes this term and a question came up:
> does FICON proper provide firewall services or is that handled by RACF and
> the external firewall of the network where the mainframe lives?
>
>
​FICON is a type of peripheral interconnection, like SATA, SCSI, or the
like. At least the FICON that I am aware of on a z machine. It has nothing
to do with security, users, firewalls, etc.

RACF is an ESM (External Security Manager) for z/OS, z/VM, z/VSE. I don't
think that there is a version for Linux on z (the topic assumed on this
forum, tho other things come here some times). On z/OS (don't know z/VM),
RACF does _not_ perform firewall type services. It only control logons
(userid + password) and access to resources, such as files (and, on z/OS,
other "resources"). You can think of RACF as being __conceptually__ similar
to a combination of PAM and SELinux on Linux. On z/OS, IP firewall services
are a part of the TCPIP stack, which is separate from the RACF security
system.

The basic firewall ability for Linux on z, like all other Linux variants,
is the iptables facility. ​I imagine that most shops also use an external
firewall router "in front of" the LAN on which the z/Linux system resides.
I cannot imagine doing it otherwise. But maybe that just a failure of my
"imaging software".

​I will likely come across as a bit harsh, but it is not my intention to be
hurtful in this. But given your questions, I am not sure that you should be
teaching a course which talks about "mainframes", if by "mainframe" you
mean the IBM z machines. I don't know the scope of your class, but the
following publications from IBM might be helpful.
http://www.redbooks.ibm.com/Redbooks.nsf/RedbookAbstracts/sg248050.html?Open
 IBM zEnterprise System Technical Introduction
http://www.redbooks.ibm.com/Redbooks.nsf/RedbookAbstracts/sg248137.html?Open
Setting up Linux on System z for production

A good starting place for information is
http://www-03.ibm.com/systems/z/hardware/index.html . But, to be very
honest, the amount of information available can be overwhelming. Perhaps
people here, or on IBM-MAIN (if you can stand the "noise" from a bunch of
us old, surly curmudgeons) could be of some help. What do you want to get
across in your class on mainframes? Do you want to compare the z hardware
versus, say, Intel's x86? Or do you want to compare the software, such as
z/OS versus Linux or VMWare versus z/VM (or the "built in" z machine's
hypervisor, called PR/SM). For an example, the Intel x86 hardware can run
OSes such as Windows, Linux, Mac OS/X, and *BSDs. The z hardware generally
runs one or more of Linux, z/VM (a hypervisor - think VMWare), z/OS, z/VSE,
or z/TPF.

-- 
​
While a transcendent vocabulary is laudable, one must be eternally careful
so that the calculated objective of communication does not become ensconced
in obscurity.  In other words, eschew obfuscation.

111,111,111 x 111,111,111 = 12,345,678,987,654,321

Maranatha! <><
John McKown

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