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Debian

Docker, an advanced chroot utility


Chasm—just like a Docker creates a chasm between two sets of software

SECURITY WARNING

Before installing Docker and containers with services on your Linux system, make sure to read and understand the risks as mentioned on this Docker and iptables page. Especially, Docker will make all your containers visible to the entire world through your Internet connection. This is great if you want to indeed share that service with the rest of the world, it's very dangerous if you are working on that container service since it could have security issues that need patching and such. Docker documents a way to prevent that behavior by adding the following rule to your firewall:

iptables -I DOCKER-USER -i eth0 ! -s 192.168.1.0/24 -j DROP

This means that unless the IP address matches 192.168.1.0/24, the access is refused. The `eth0` interface name should be replaced with the interface name you use as the external ethernet connection. During development, you should always have such a rule.

That has not worked at all for me because my local network includes many other computers on my LAN and this rule blocks them all. So really not a useful idea.

Instead, I created my own entries based on some other characteristics. That includes the following lines in my firewall file:

*filter
:DOCKER-USER - [0:0]

-A DOCKER-USER -j early_forward
-A DOCKER-USER -i eno1 -p tcp -m conntrack --ctorigdstport 80 --ctdir ORIGINAL -j DROP
-A DOCKER-USER -i eno1 -p tcp -m conntrack --ctorigdstport 8080 --ctdir ORIGINAL -j DROP
-A DOCKER-USER -i eno1 -p tcp -m conntrack --ctorigdstport 8081 --ctdir ORIGINAL -j DROP

My early_forward allows my LAN to continue to work. These are my firewall rules that allow my LAN computers to have their traffic forwarded as expected.

Then I have three rules that block port 80, 8080, and 8081 from Docker.

Docker will add new rules that will appear after (albeit not within the DOCKER-USER list) and will open ports for whatever necessary service you install in your Dockers.

Note that the only ports you have to block are ports that Docker will share and that you have otherwise open on your main server. If Docker opens port 5000 and your firewall does not allow connections to port 5000 from the outside, then you're already safe. On my end I have Apache running so as a result I block quite usual HTTP ports from Docker.

Docker

As we are helping various customers, we encounter new technologies.

In the old days, we used chroot to create a separate environment where you could have your own installation and prevent the software from within that environment access to everything on your computer. This is particularly useful for publicly facing services liek Apache, Bind, etc.

Upgrade to PHP 5.3.3 or newer because of security issue

If you are responsible for a Debian or Ubuntu server and run PHP on it, make sure to run the following command to fix several security issues found in PHP:

sudo apt-get install php5-suhosin

This will make the necessary and your PHP version (security wise) will look like you have PHP 5.3.3.

What I found quite annoying in regard to this issue is the fact that it was very difficult to find a mention of this upgrade. All I could find in large number were people saying that you'd have to get an upgrade using the source code of PHP. Somehow, I did not feel like upgrading PHP from ...

Turn Watcher™

$14.99

The Turn Watcher Helmet with wings on the side and a gold medallion on the front.Turn Watcher™ is a Combat Initiative Tracker by Made to Order Software! Turn Watcher was created by gamers for gamers to help you run your combat rounds more smoothly and efficiently.

Turn Watcher keeps track of the combat order of each player character (PC) and monster involved in your encounters by tracking player and monster initiative order and current hit points so you don't have to!

Turn Watcher lets you make secret skill checks and will saves for player characters. It manages the PCs and monsters that have delayed or readied actions. And it handles automatic bleed out of dying PCs and monsters!

$14.99

Made to Order Software releases Turn Watcher 1.4 and a new website!

Made to Order Software is proud to announce the release of Turn Watcher version 1.4 and a brand new website!

Turn Watcher version 1.4 incorporates not only some much needed bug fixes (specifically the Stabilize function) but the addition of a brand new feature: Soft Columns.

Use Soft Columns to add, edit and remove rolls and information columns to each of your combatants. For example, you may remove the Spot/Listen columns and replace them with Perception. Add new rolls such as Move Silently and Persuasion. You may also add information-only columns such as Armor Class and Condition Track, ...

Turn Watcher 1.3 is out!

Made to Order Software Corporation is proud to announce the 1.3 release of Turn Watcher, an Initiative and Effects Tracker... and more!

Version 1.3 includes many bug fixes making the interface run faster especially with a large number of combatants.

Also, we added support to display a second window with the characters and monsters. Window that you can show to your users on a second monitor! The Heads Up Display or HUD is a window with limited viewing so you can show what you choose to show to your players.

Turn Watcher is supported on all of the following systems:

  • Microsoft Windows ...

Turn Watcher 1.2 is out!

Made to Order Software Corporation is proud to announce the 1.2 release of Turn Watcher, an Initiative and Effects Tracker...and more!

Version 1.2 now supports spell and other effect tracking. A optional new window appears at the bottom of the main window that allows you to add, edit and remove effects for the currently highlighted combatant. When an effect expires on the current combatant's turn, you are alerted and asked if you wish to delete the expired effect.

You may also add effects to multiple characters at once by highlighting them, then clicking the "A" button. ...

Turn Watcher 1.1 is out!

Made to Order Software Corporation is proud to announce the 1.1 release of Turn Watcher, the best GM's Initiative Manager!

For those of you who bought the 1 year's worth of updates for Turn Watcher back in 2006, we have really good news: we extended the duration of your privilege to download newer versions until the end of 2007!

Version 1.1 includes an optional initiative window which allows manual entry of initiative rolls for all combatants. Now you can let players make their own initiative rolls!

Use the Spot/Listen/Will roll feature a lot? Now Turn Watcher automatically sorts ...