Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!lll-winken!uunet!mcvax!ukc!cam-cl!scc From: scc@cl.cam.ac.uk (Stephen Crawley) Newsgroups: comp.protocols.tcp-ip Subject: Re: IP based authentication of hosts Message-ID: <710@scaup.cl.cam.ac.uk> Date: 14 Apr 89 05:33:45 GMT References: <376@ists.ists.ca> <29416@bu-cs.BU.EDU> <29455@bu-cs.BU.EDU> <10526@bloom-beacon.MIT.EDU> <29475@bu-cs.BU.EDU> <10540@bloom-beacon.MIT.EDU> <29549@bu-cs.BU.EDU> Sender: news@cl.cam.ac.uk Organization: U of Cambridge Comp Lab, UK Lines: 41 Kent England writes: > My secure subnet might be a delni in a locked equipment rack. Are the computers inside the locked equipment rack as well? If not, what is to stop JR User from plugging a PC into a drop cable? Suppose that you do put the computers in the locked rack, how do your users access the machines? Lots of 9600 baud async lines? [You can't provide terminal over your LAN without sending network traffic off your physically secure subnet!] What are you going to say to the users who want to use a PC or a workstation? Do the physically secure machines on the LAN run a secure OS? If not, what is to stop JR Hacker from indulging in a bit of unauthorised spade work on the OS kernel to give himself access to ethernet packets? [Don't tell me that JR Hacker =/= JR User. What if he is and you don't know about it? What if he is and you DO know about it?!] What are you going to say to your users who want to use ... say ... UNIX? > I am not trying to secure my nets against the KGB, so don't tell me > you can crack any net I design and install. Just who are you trying to make the system secure against? Cleaning ladies? An undergraduate CS hacker wouldn't have much trouble finding a way through your scheme ... given a big enough carrot. Certainly the undergrads around here wouldn't! I want security that is on the same level as me keeping sensitive materials in a locked filing cabinet inside a locked office with the nightwatchman walking the corridors. At the same time I want to use a nice bitmapped workstation with several MIPs of local processing power [In 5-10 years time I'll expect an integrated services workstation.] I do NOT want to be forced to use a klunky old 24 by 80 on a 9600 baud terminal line. I do NOT want to have to go down the corridor to the secure room every time I want to read my email. I claim that security without substantial inconvenience is achievable using encrypted protocols, but not with a physical security scheme. -- Steve