Linux – Tool to log all incoming, outgoing traffic, apache server load etc

Attempting to expand on @Zoredache's answer, as I give this a go myself:

• Create a new group (www-pub) and add the users to that group

  groupadd www-pub

  usermod -a -G www-pub usera ## must use -a to append to existing groups

  usermod -a -G www-pub userb

  groups usera ## display groups for user

• Change the ownership of everything under /var/www to root:www-pub

  chown -R root:www-pub /var/www ## -R for recursive

• Change the permissions of all the folders to 2775

  chmod 2775 /var/www ## 2=set group id, 7=rwx for owner (root), 7=rwx for group (www-pub), 5=rx for world (including apache www-data user)

  Set group ID (SETGID) bit (2) causes the group (www-pub) to be copied to all new files/folders created in that folder. Other options are SETUID (4) to copy the user id, and STICKY (1) which I think lets only the owner delete files.

  There's a -R recursive option, but that won't discriminate between files and folders, so you have to use find, like so:

  find /var/www -type d -exec chmod 2775 {} +

• Change all the files to 0664

  find /var/www -type f -exec chmod 0664 {} +

• Change the umask for your users to 0002

  The umask controls the default file creation permissions, 0002 means files will have 664 and directories 775. Setting this (by editing the umask line at the bottom of /etc/profile in my case) means files created by one user will be writable by other users in the www-group without needing to chmod them.

Test all this by creating a file and directory and verifying the owner, group and permissions with ls -l.

Note: You'll need to logout/in for changes to your groups to take effect!

Many people seem to be afraid of mixing stable with testing, but frankly, testing is fairly stable in its own right, and with proper preferences and solution checking, you can avoid the "stability drift" that puts your core packages on the unstable path.

"Testing is fairly stable??", you ask. Yes. In order for a package to migrate from unstable to testing, it has to have zero open bugs for 10 consecutive days. Chances are that, especially for the more popular packages, somebody is going to submit a bug report for an unstable version if something is wrong.

Even if you don't want to mix the environments, it's still nice to have the option there in case you run into something that requires a newer version than what is in stable.

Here's what I recommend for setting this up:

First, create the following files in /etc/apt/preferences.d:

stable.pref:

# 500 <= P < 990: causes a version to be installed unless there is a
# version available belonging to the target release or the installed
# version is more recent

Package: *
Pin: release a=stable
Pin-Priority: 900

testing.pref:

# 100 <= P < 500: causes a version to be installed unless there is a
# version available belonging to some other distribution or the installed
# version is more recent

Package: *
Pin: release a=testing
Pin-Priority: 400

unstable.pref:

# 0 < P < 100: causes a version to be installed only if there is no
# installed version of the package

Package: *
Pin: release a=unstable
Pin-Priority: 50

experimental.pref:

# 0 < P < 100: causes a version to be installed only if there is no
# installed version of the package

Package: *
Pin: release a=experimental
Pin-Priority: 1

(Don't be afraid of the unstable/experimental stuff here. The priorities are low enough that it's never going to automatically install any of that stuff. Even the testing branch will behave, as it's only going to install the packages you want to be in testing.)

Now, creating a matching set for /etc/apt/sources.list.d:

stable.list: Copy from your original /etc/apt/sources.list. Rename the old file to something like sources.list.orig.

testing.list: Same as stable.list, except with testing.

unstable.list: Same as stable.list, except with unstable, and remove the security lists.

experimental.list: Same as unstable.list, except with experimental.

You can also add a oldstable in sources.lists.d and preferences.d (use a priority of 1), though this moniker will tend to expire and disappear before the next stable cycle. In cases like that, you can use http://archive.debian.org/debian/ and "hardcode" the Debian version (etch, lenny, etc.).

To install the testing version of a package, simply use aptitude install lib-foobar-package/testing, or just jump into aptitude's GUI and select the version inside of the package details (hit enter on the package you're looking at).

If you get complaints of package conflicts, look at the solutions first. In most cases, the first one is going to be "don't install this version". Learn to use the per-package accept/reject resolver choices. For example, if you're installing foobar-package/testing, and the first solution is "don't install foobar-package/testing", then mark that choice as rejected, and the other solutions will never veer to that path again. In cases like these, you'll probably have to install a few other testing packages.

If it's getting too hairy (like it's trying to upgrade libc or the kernel or some other huge core system), then you can either reject those upgrade paths or just back out of the initial upgrade altogether. Remember that it's only going to upgrade stuff to testing/unstable if you allow it to.

EDIT: Fixed some priority pins, and updated the list.