Postfix question

[Waldher, Travis R]

> -----Original Message-----
> From: Rick Stevens [mailto:rstevens at vitalstream.com] 
> Sent: Thursday, September 30, 2004 11:33 AM
> To: Getting started with Red Hat Linux
> Subject: Re: Postfix question
> 
> Waldher, Travis R wrote:
> >>-----Original Message-----
> >>From: Bob McClure Jr [mailto:robertmcclure at earthlink.net]
> >>Sent: Thursday, September 30, 2004 10:12 AM
> >>To: Getting started with Red Hat Linux
> >>Subject: Re: Postfix question
> >>
> >>On Thu, Sep 30, 2004 at 09:30:01AM -0700, Waldher, Travis R wrote:
> >>
> >>>Under a directory
> >>>
> >>>/var/spool/postfix/etc
> >>>
> >>>There are files such as hosts, resolv.conf, etc.  Which are
> >>
> >>supposed
> >>
> >>>to be copies of the /etc files.
> >>>
> >>>Why aren't these files just links to /etc so it would
> >>
> >>always test ok,
> >>
> >>>and if those files changed, postfix would change
> >>
> >>automatically (minus
> >>
> >>>having to run reload).
> >>
> >>They might possibly be hard links, but only if /etc and 
> >>/var/spool/postfix/etc are on the same filesystem.  A symlink won't 
> >>work in the chroot environment.  But some editors or change 
> processes 
> >>will break hard links, so that may not even work.
> >>
> >>Cheers,
> >>-- 
> >>Bob McClure, Jr.             Bobcat Open Systems, Inc.
> >>robertmcclure at earthlink.net  http://www.bobcatos.com Grace happens.
> > 
> > 
> > They aren't hard links, editing one, doesn't show up as a change in 
> > the other.
> > 
> > So the question becomes, does postfix modify in anyway, those files 
> > under postfix/etc.
> 
> No, it doesn't modify the files, but remember that postfix 
> runs in a chrooted environment.  Links (be they symbolic or 
> hard) can't back up beyond what the chroot directory is, so 
> postfix won't be able to see the targets of the links. That's 
> why it needs local copies and not links to the system files.
> 
> This is similar to setting up a chrooted anonymous FTP 
> server...if you want user and group names to be displayed for 
> the "ls" command, the FTP server must have copies of 
> /etc/passwd and /etc/group in its own filesystem.

This is where I don't understand.  Under an ext3 filesystem (one I'm
more familiar with).  If you create a hard link between two files, they
now share the same inode.

So why would you have an issue with being at to backup beyond what the
chroot directory is?  Postfix should just see that hosts under
postfix/etc is a file and not know that it's a hard link.  :confused: