Rolf's questions

I have noticed that installing sendmail, then uninstalling it, using apt-get will leave many unwanted files behind.

sudo apt-get install sendmail
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
  liblockfile-bin liblockfile1 make procmail sendmail-base sendmail-bin
  sendmail-cf sensible-mda
Suggested packages:
  make-doc sendmail-doc rmail logcheck resolvconf sasl2-bin
Recommended packages:
  default-mta mail-transport-agent fetchmail
The following NEW packages will be installed:
      liblockfile-bin liblockfile1 make procmail sendmail sendmail-base
      sendmail-bin sendmail-cf sensible-mda
0 upgraded, 9 newly installed, 0 to remove and 0 not upgraded.
Need to get 2256 kB of archives.
After this operation, 5263 kB of additional disk space will be used.
Do you want to continue? [Y/n] y

So we installed sendmail - 9 new packages and 5.2MB.
Minutes later, I changed my mind and want to uninstall it. No problem, apt-get got me covered, right? I purge (delete package and package configuration files):

sudo apt-get purge sendmail
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  procmail sensible-mda
Use 'apt-get autoremove' to remove them.
The following packages will be REMOVED:
  sendmail*
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
After this operation, 219 kB disk space will be freed.
Do you want to continue? [Y/n] y

Then autoremove (remove automatically installed package dependencies)

sudo apt-get autoremove sendmail
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package 'sendmail' is not installed, so not removed
The following packages will be REMOVED:
  procmail sensible-mda
0 upgraded, 0 newly installed, 2 to remove and 0 not upgraded.
After this operation, 550 kB disk space will be freed.
Do you want to continue? [Y/n] y
(Reading database ... 24702 files and directories currently installed.)
Removing sensible-mda (8.14.4-8+deb8u1) ...
Removing procmail (3.22-24) ...
Processing triggers for man-db (2.7.0.2-5) ...

That's 219 + 550 = 769KB recovered! Did I just loose 4.something MB of space? For what?

Upon looking closely at the output, it appears that apt-get removed only 3 of the package that it previously automatically installed. Package sendmail-base, for example, remains:

sudo apt-get remove sendmail-base
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
  sendmail-base sendmail-bin
0 upgraded, 0 newly installed, 2 to remove and 0 not upgraded.
After this operation, 2464 kB disk space will be freed.
Do you want to continue? [Y/n]

So there is some of my wasted space. But why are these automatically installed dependencies still installed?

I've setup a web server for production use. The OS is Windows Server, and it runs Apache 2.0 and PHP 5.3 as an apache module (and MySQL too...). It is used to host several virtual hosts (Apache vhosts) belonging to different customers.

At this point PHP is running as the system user. In the future FTP access might be granted to customers, so - by default - every customer would be able to access the whole system through PHP. That is obviously unacceptable.

I understand that I can set open_basedir in PHP, yet I am not sure if it is encompassing and solid enough to be considered a solution - does it limit access on all PHP functions, such as include...? How about PHP streams?

I also know that IIS offers a solution to that problem, but I prefer to keep Apache.

What I would ideally like to set up, is a solution that would fulfill the following requirements (mainly):

• Be elegant and somehow automatic. I am manually managing the server - I want the setup of each vhost to involve the least amount of setup and configuration editing as possible.
• Allow for an exception. Most hosted websites are developed by myself, and I'd like to link all of them to a single library folder, so read-only access should be allowed to that folder although it would be outside the root of the vhost.

So, what are the options available, if any? I already did some research and it seems that most work in that field was done on Linux systems.