Noob Jail question.

Dave dave at
Wed Dec 15 23:32:24 UTC 2010


As some of you may remember, I've managed to build a F'BSD V8.0 based 
system that provides me with:-

Local GPS disiplined NTP server (working very well) the reason I built 
the thing in the first place, but it seems FreeBSD can do so much more, 
so I also have.....

Hiawatha webserver (also working well)

FTPD for updating the web pages Hiawatha serves up (working well)  Other 
systems here generate data, that is FTP'd over the LAN to the web page 

SSH remote login for admin needs (But not for "root" login) Also working 

All this will start happily, boot and sort itself out as a "headless" 
machine, and if needed collapse gracefully and shutdown cleanly, with one 
press of the power button.  I am impressed!

I've been reading the FreeBSD Manual (a dangerous thing to do during 
lunchtimes!) relating to Jails.  Other than making my head spin, I'm 
finding it a tad dificult finding out just what you can/cant do with a 
Jail.  Mainly, because I'm not familiar with a lot of the terms used, and 
though the man pages are no doubt correct as a reference, they don't 
"explain" it well, in as much as how to use it, well in my addled mind at 
the moment.

I think I'd like to run Hiawatha in a Jail, as it seems "the right thing 
to do" with something that will be exposed to the www.  

But, how do I arrange it to safely get (read only) access to the website 
data, without preventing the FTPD service from having access to update 
that data.  FTPD will only be reachable from LAN side of the main gateway 
router, Hiawatha will have an outside world port forwarded to it by the 

What I'm asking I guess, is..  Can a jail'd app, reach outside the jail 
in "read only" mode.   (I suspect, maybe?)   Or can an app outside the 
jail, drop stuff off inside the jail?  (For whatever reason, I suspect 

If anyone understands what the heck I'm blathering on about, please 
explain it to me, as I think I've lost the plot.

Comments, advice, brickbats etc?

Best Regards.

Dave B.

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