Great Circle Associates Firewalls
(September 1995)
 

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Subject: Re: Frame Relay firewalls???
From: Ken Hardy <ken @ bridge . com>
Date: Fri, 29 Sep 95 11:45:11 CST
To: anton @ the-wire . com
Cc: firewalls @ greatcircle . com, thierry @ namsa . nato . int

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Date: Fri, 29 Sep 1995 10:34:47 -0500
From: Ken Hardy <ken @
 bridge .
 com>
Message-Id: <199509291534 .
 AA23462 @
 ignatz .
 bridge .
 com>
To: anton @
 the-wire .
 com
Subject: Re: Frame Relay firewalls???
Cc: firewalls @
 greatcircle .
 com, thierry @
 namsa .
 nato .
 int
Sender: firewalls-owner @
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 COM
Precedence: bulk

Per Anton J Aylward <anton @
 the-wire .
 com>:

>>> breaches are conducted using IP.  Traditional IP firewalls require
>>> packet reassembly for ATM networks.  This has the disadvantage of
>>> introducing latency and is a performance bottleneck for otherwise high
>>> performance ATM networks.  That means that most IP traffic traversing
>>> ATM networks is unprotected."
...
>I don't imagine that ATM swithces are any harder to hack than Frame Relay or
>"voice".
>Or vice versa.
...
>Re your quote: I don't see what packet re-assembly and altency has to do
>with the trafic being unprotected.
>Even if your data was in a single packet it could still be hijacked, cloned
>or whatever.

I believe that the initial quote is not talking about the switches
themselves, but just to the IP traffic which comes via ATM; the
company, which obviously has a product to sell and may be skewing
reality a bit, seems to claim that ordinary IP firewalls need the whole
IP packet, requiring reassembly.

ATM packets are small and fixed sized -- 5 bytes header and 48 bytes
payload.  Don't recall details of what I read about IP over ATM (a
recent Computer Communications Review had an issue devoted to ATM --
v25n2 04/95), but I assume that the IP packets are spread among several
ATM packets, rather than using IP fragmentation and having an entire IP
packet, albeit a fragment, in each tiny ATM packet.  (Corrections
welcome.)

It appears that this outfit has some sort of IP firewall (maybe just a
screen) for ATM that works without reassembling the IP packets,
achieving lower latency.

It would be interesting to know what they have and what real extra
value it offers.  I posted the original press release.  After having
done so, I repented somewhat and thought that perhaps I should just
have posted their URL for those really interested.  But if it initiates
a discussion here that helps increase general knowledge of these issues
(like whether or not they're significant), without too much noise, it
may be for the best.

- KH


Indexed By Date Previous: Re: Choice of secure router software
From: Jennifer_Bayuk @ notes . pw . com
Next: Re: regarding RFC1597 networks and DNS
From: Yakov Rekhter <yakov @ cisco . com>
Indexed By Thread Previous: Re: Frame Relay firewalls???
From: Anton J Aylward <anton @ the-wire . com>
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From: Tham Huei Hwan <Tham . Huei . Hwan @ bass . com . my>

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