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From: sid@linus.UUCP (Sid Stuart)
Newsgroups: net.mail,net.unix-wizards
Subject: Re: rerouting mail after a timeout
Message-ID: <132@linus.UUCP>
Date: Mon, 20-Jan-86 10:36:01 EST
Article-I.D.: linus.132
Posted: Mon Jan 20 10:36:01 1986
Date-Received: Thu, 23-Jan-86 08:27:40 EST
References: <5651@allegra.UUCP>
Reply-To: sid@linus.UUCP (Sid Stuart)
Organization: The MITRE Corporation, Bedford, MA
Lines: 64
Xref: watmath net.mail:1378 net.unix-wizards:16473

>Many users here do most of their work on Suns, using the central vaxes
>only for reading mail and netnews.  I've gotten quite a few requests
>from some users wondering if it's possible to change their aliases to
>route their mail to their Suns (since this would save them the trouble
>of having to manually copy saved mail messages from the vaxes to the
>Suns) yet be assured that if they turn off their Suns for a long period
>of time without telling anyone (e.g. to go on vacation) that their mail
>will then be automatically rerouted to a vax rather than being returned
>to the sender.  Has anyone enhanced sendmail's timeout mechanism (or
>written a separate tool that grovels through the queue files) to do
>something like this?
>
>	Mark Plotnick
>	allegra!mp


	The nicest solution to this problem would be to have only one
/usr/spool/mail directory across your network of computers.
Having only one /usr/spool/mail directory means that whatever computer
you log into, you read the same mail.  I don't think it would take more than
a week or two of work to do, unfortunatly I haven't had a week or two to do it
yet. I am hoping Sun will do it in Release 3.0. Here is the idea,

		1) Sendmail.cf changes:
		 Have the computers route all their mail to a main machine,
		lets call it the mailhost. This would mean that the
		subsidiary machines, lets call them nomailhosts, would
		not have a local mailer specified in their sendmail.cf.
		The mailhost would also rewrite the addresses coming
		from the nomailhosts to make it appear as if the mail
		was sent from the mailhost. The mailhost would also
		accept mail sent to the nomailhosts and deliver it
		via the local mailer.


		2) Directory changes:
		Set up the mailhost's /usr/spool/mail directory
		normally. Have the mailhost's /usr/spool/mail mounted
		on the nomailhost machines through the NFS.

		3) Software changes:
		This is the hard part. Sendmail, /bin/mail and
		/usr/ucb/mail and probably any other mail readers/deliverers
		want to coordinate spooled mailfile activity through lockfiles.
		They have a timeout check on the creation date of the
		lockfile. To make sure that that time skew on different
		machines doesn't burp on this feature and to fix any posible
		wierd race problems that I don't want to consider, one
		needs a lock server. It would be easy to implement the lock
		server using Sun's RPC, but it would take a week or so for me
		to do it.(Which I don't have.)

		
	The above changes require that you have NFS running on your Vax. This
is available from Mt. Xinu.


	You can also have your users read news on the Suns, just mount the
news spool directory with the NFS and install the news reader on the Suns.


						sid at linus