forcing FTP-uploaded files to be of certain types only

[David J. Orman]

The stock ftp server? If you can't base the prohibitions on file extension alone (such as the 100kb example you made) then you're going to have to modify the source of the ftp daemon yourself. Size, extension, etc - those are relatively easy limits to impliment. Actual file typing by examination of the first 100kb isn't easy, and it isn't part of the core functionality AFAIK. You'll have to write that. In fact, I'm not aware of any ftp server that does what you're asking.

Maybe it would be better to examine files periodically that were uploaded via a simple program, and anything that isn't allowed, destroy. You could also make it compress things that weren't compressed to begin with, etc etc etc.

Good luck,
David

----- Original Message -----
From: Mikhail Teterin <mi+mx at aldan.algebra.com>
Date: Monday, July 17, 2006 7:06 am
Subject: forcing FTP-uploaded files to be of certain types only

> Hello!
> 
> We run an FTP server for the customers to upload their data 
> (usually -- giant 
> core-files and database-dumps).
> 
> Sometimes they forget compress them, however, wasting many 
> gigabytes of our 
> server's space...
> 
> How hard would it be to make the stock FreeBSD FTP-server to 
> examine the 
> first, say, 100Kb of the uploaded file and interrupt transfer if 
> the file is 
> of a prohibited or is not of an allowed type?
> 
> Anything under 100Kb is fine, I guess, and 100Kb is more than 
> enough to detect 
> compression or lack thereof...
> 
> Thanks for ideas!
> 
> 	-mi
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