On Tue, 3 Feb 1998, Greg A. Woods wrote:
> [ On Tue, February 3, 1998 at 10:35:46 (-0800), Tom wrote: ]
> > Subject: Re: [EXIM] Maximum Message Size
> >
> > You offer no arguements here on why you think 1MB is "very excessive".
>
> 10MB is extremely excessive for anyone on a 28.8Kbps link. Some of my
> ISP clients end up deleting user mailboxes because of only 5MB messages,
> even when the client would really like to download the message they
> can't (usually due to either lack of patience, brain-dead PC clients, or
> both). If every user had a high-speed cable modem, xDSL link, or even
> ISDN line, then this would not be an issue, but a tremendously large
> portion of the Internet's e-mail users still have low-speed connections.
Well, there are some people who have problems. But the majority of
users that I surveyed like the 10MB limit, and can handle it.
...
> > I don't really care about the connectivity of other sites. If they
> > don't want large mails, they can refuse to accept them. As you stated in
> > a previous message, setting up an e-mail system on the Internet implies
> > certain responsibilities (your wording was much better).
>
> Unfortunately the protocols currently in all-too-common use don't allow
> the receiving site (and never the recipient) to accept total
> responsibility for controlling such limits. To implement them fully
> would require that a site completely reject non-ESTMP connections, and
Rejecting non-ESMPT would be extreme. Most mail systems are ESMTP now,
and if control of large e-mail is important to a site, implmenting ESMTP
should be important too. Sure, sites using plain SMTP can slip large
messages through
> to implement them for the user would require that everyone avoid POP and
> use only IMAP or something similar where control over the spool file can
> be had without first downloading it.
I don't understand the relevance. If you want to have user controls,
you want to control the amount of e-mail going into a box, not how users
get it out?
> [[You should see what 8,000 POP users over over high speed links can do
> to a large and well endowed Sparc-Ultra when they all hit the POP server
> every 5-60 seconds, esp. when those users inevitably learn to keep large
...
You should get a real server, or you should use Exim :)
Users coming over slow connections are worse, because more are in
progress are any one time. A client system that I manage handles 15,000
POP and IMAP users, each with a 10MB limit, accepting about 900MB to
1000MB of new mail per day. It receives over 60,000 POP/IMAP logins per
day. Load average is about 0.60 during heaviest load.
Also, just say no to bezerk mailboxes, as they terrible on large mail
servers.
...
> > Critical security measure?
>
> Too many large messages can easily crash or lock up the mail system (or
> indeed one large one has been shown to crash some mail systems), even a
> well designed one that ordinarily can carry enormous traffic loads
Again, this is resposibility of that site. If it really important, they
can setup an outside relay to protect fragile internal mail systems.
...
> Even worse some mail systems are so persistent that they can repeatedly
> crash the receiving mailer as quickly as you can reboot it. We had this
> happen several times at a client site where smail would almost instantly
...
Same thing. I refer you to your own comments in regards to admins of
mail systems faced with spam problems. Your conclusion was that admins
(and those sites) need to take responsiblity for their own problems.
Again, your wording was better, and I really should dig this out of the
archive.
> > What background are you from? It doesn't seem that you've worked
> > on a significant real-world mail system before.
>
> I thought this mailing list was above such things..... ;-)
Well, when I sent this message, your mail server was unreachable,
so I wasn't even sure if you'd get this message :)
Also, planix.com (your employer?) has a 2MB limit. What's the deal with
that? :)
...
> --
> Greg A. Woods
>
> +1 416 443-1734 VE3TCP <gwoods@???> <robohack!woods>
> Planix, Inc. <woods@???>; Secrets of the Weird <woods@???>
Tom
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