Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site hou4b.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!ihnp4!houxm!vax135!ariel!hou4b!dwl From: dwl@hou4b.UUCP (D Levenson) Newsgroups: net.unix-wizards,net.dcom Subject: Re: Dial Back isn't always secure Message-ID: <1348@hou4b.UUCP> Date: Wed, 6-Mar-85 13:32:22 EST Article-I.D.: hou4b.1348 Posted: Wed Mar 6 13:32:22 1985 Date-Received: Thu, 7-Mar-85 05:53:03 EST References: <1226@amdahl.UUCP> Organization: AT&T Information Systems Laboratories, Holmdel, NJ Lines: 15 Xref: watmath net.unix-wizards:12326 net.dcom:890 Multiple-hop call forwarding IS permitted, at least it is in the local ESS / ESSX switches with which I have dealt here in NJ. What prevents endless forwarding in the case of circular forwarding is as follows: If line A forwards its incoming calls to line B, then A will appear busy to other incoming calls, for the duration of any call it has forwarded to B. In other words, if you dial A's number and the call is forwarded to B, then if you or anyone else dials A's number, a busy signal will be returned if your call to B via A is still in progress. A circular forward loop can only be established between telephones served by physically separate central offices. In this case, any call dialed to any member of the circular list will hunt once around and reach a busy signal! Dave Levenson ATT-IS, Holmdel