From owner-freebsd-questions Tue Jul 11 20:35:53 1995 Return-Path: questions-owner Received: (from majordom@localhost) by freefall.cdrom.com (8.6.10/8.6.6) id UAA17380 for questions-outgoing; Tue, 11 Jul 1995 20:35:53 -0700 Received: from sbstark.cs.sunysb.edu (sbstark.cs.sunysb.edu [130.245.1.47]) by freefall.cdrom.com (8.6.10/8.6.6) with ESMTP id UAA17373 for ; Tue, 11 Jul 1995 20:35:51 -0700 Received: (from root@localhost) by sbstark.cs.sunysb.edu (8.6.12/8.6.9) with UUCP id XAA07135 for questions@freebsd.org; Tue, 11 Jul 1995 23:34:07 -0400 Received: (from gene@localhost) by starkhome.cs.sunysb.edu (8.6.11/8.6.9) id IAA09799; Tue, 11 Jul 1995 08:49:09 -0400 Date: Tue, 11 Jul 1995 08:49:09 -0400 From: Gene Stark Message-Id: <199507111249.IAA09799@starkhome.cs.sunysb.edu> To: Michael Smith Cc: questions@freebsd.org In-reply-to: Michael Smith's message of Tue, 11 Jul 1995 09:57:50 +0930 (CST) Subject: Re: PPP and demand start References: <3tsr1d$7km@starkhome.cs.sunysb.edu> Sender: questions-owner@freebsd.org Precedence: bulk >What you probably want is for the link not to drop while you have a TCP >connection open on a remote system. Unfortunately, it's impossible >to detect this, as an open TCP connection normally only generates >traffic (which can be detected) when it's doing something. Nontrivial, but not impossible. The PPP process can track the state of the TCP connection, as it has access to all the packets in both directions. The "dp" package that runs on Sparc's does this, though the dp-2.3 version I have used is not totally reliable in this respect. The PPP process under FreeBSD does not do this type of thing, but it could if somebody coded it. - Gene Stark