Firewall/Mainframe info

[Eriktauber <Eriktauber @ aol . com>]

I am looking for information about firewall protection for mainframes.

Also, I need data about how to secure a site that has an Internet connection
and mainframe boxes, mainly IBM 3090 from an outside attack.  

It seems that all of the literature about firewalls deal only in the Unix/NT
realm and ignore the mainframe world.

Any help about where such info could be found is appreciated.

Thanks

Erik