[unisog] Size Limit on E-Mail Attachments

William D. Colburn (aka Schlake) wcolburn at nmt.edu
Mon Nov 5 19:19:01 GMT 2001


I have to agree about the difficulties of setting up good FTP sites.  If
only a couple of people make things available for download, then
administration is easy, but if anyone on campus can do it then it
becomes a nightmare.  Web pages are just as bad.  I've found people who,
in the intrest of getting things done more quickly, made symbolic links
in their web-space that allowed them to see the entire filesystem, run
arbitrary commands (like xterm -display), start internet servers (like
IRC), etc.

Email is a perfectly acceptable method for transferring files, and I
think it is better suited than FTP and HTTP for a lot of applications.
It has about the same network overhead as FTP and HTTP but is a
point-to-point server-push protocol while FTP and HTTP are a passive
client-pull protocols.  It also has a lot less overhead work for the
sender.  If I am going to make a file available to someone over
FTP/HTTP, I need to put it there, inform them of it, verify they got it,
then remove it.  If I am going to make something available to someone
via email then I send it to them, and if they don't get it then it will
be mailed back to me, otherwise I can just assume it made it.  If the
file is confidental, then it adds even more steps to the FTP/HTTP to
make sure that the curious don't download it by mistake, but SMTP is
already confidential so no extra steps are needed.

The file size limits I see some people supporting are absolutely
ludicrous.  What if a user is blind, so just "talks" to his email client
then sends the recoded monolog.  A short email message could easily be
more than five megabytes, and it would certainly be an attachement, but
it is also quite obviously a perfectly valid email message.

On Mon, Nov 05, 2001 at 10:18:50AM -0600, Graham Allan wrote:
> It is possible to set up a secure, writable anonymous ftp site. All
> that's required is that anonymously uploaded files can't be accessed
> again by anonymous users (or even by any ftp users at all - leave them
> accessible only to internal users of the system).
> 
> It's incredibly tedious to get this right using most vendor-supplied ftp
> servers. An aftermarket server like ncftpd which enforces these policies
> internall,y regardless of the underlying filesystem permissions, helps a
> great deal.
> 
> Graham
> -- 
> -------------------------------------------------------------------------
> Graham Allan - I.T. Manager - allan at physics.umn.edu - (612) 624-5040
> School of Physics and Astronomy - University of Minnesota
> -------------------------------------------------------------------------

--
William Colburn, "Sysprog" <wcolburn at nmt.edu>
Computer Center, New Mexico Institute of Mining and Technology
http://www.nmt.edu/tcc/     http://www.nmt.edu/~wcolburn



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