Joseph S D Yao <jsdy@center.osis.gov> writes:
Dave,
I think the mail gateways back when the various networks were being put together into an internet had as their functional purpose unifying disparate networks. On the contrary, a firewall has as its purpose partitioning a network that otherwise would not have been.
When ARPA and MILNET were segmented in 1984, there were (Fuzzball-based IIRC) mail gateways between the two networks. The intended purpose of these devices was to restrict inter-network traffic to only email between two networks that were formerly one, so they're best looked at as a policy enforcement tool rather than a unifier the same way that, say, WISCVM.BITNET or ...!uunet!... was. It's not clear to me whether they were simply packet filters or actual application level gateways (given the capabilities of the fuzzball, my inclination is to think the former, but it's still worth taking note of). Besides, I was in high school at the time; it's not as if I had anything to do with the actual implementation. Those of a historical mind are encouraged to read Request For Kludges 821 - SMTP Polymorph Command: http://www.ibiblio.org/pub/docs/humor/fionavar/rfk_821 You may also find this interesting (particularly "On the Undesirability of 'Mail Bridges' as a Security Measure" by the late Mike Muuss); "walled garden" complaints and griping about gratuitously hosing the end-to-end model far predate the last decade and the lossage imparted by NAT: http://www.scatteredsheep.com/darpa-arpa-internet.htm
I don't think one will hear from MIT, given that.
As much time as I've spent hanging out at MIT over the years, I don't count. ;-) ---Rob