diff --git a/README.md b/README.md
index 55a1cf5..4326ab6 100644
--- a/README.md
+++ b/README.md
@@ -26,7 +26,7 @@ These can be installed for a single user (recommended), in a python virtual envi
 pip install --user cherrypy mako markdown pyyaml pygments sqlalchemy bcrypt
 ```
 
-#### Installing packages in a virtual environment
+#### Installing packages in a virtual environment (alternative)
 
 ```.bash
 pyvenv-3.5 venv/perguntations              # or other virtualenv directory
@@ -35,7 +35,7 @@ source venv/perguntations/bin/activate     # activate virtualenv
 pip install cherrypy mako markdown pyyaml pygments sqlalchemy bcrypt
 ```
 
-#### Installing packages system wide
+#### Installing packages system wide (alternative)
 
 I personally prefer python packages to be installed for a single user, but if a system wide installation is required, it is probably better to use the operating system package manager instead of `pip`:
 
@@ -53,7 +53,9 @@ where USERNAME is your account on bitbucket.
 
 ## Running a demo
 
-The following commands show how to run a demonstration test:
+The directory `demo` includes a demo test that can be used as a template for your own tests and questions.
+
+To run the demonstration test:
 
 ```.bash
 cd WHERE/YOU/INSTALLED/perguntations
@@ -62,14 +64,13 @@ cd WHERE/YOU/INSTALLED/perguntations
 ./initdb.py students.csv    # from CSV file
 ./initdb.py --demo          # initialize with fake students
 ./initdb.py                 # empty
-
 mv students.db demo/
 
+# create directory to put the student's answered tests
+mkdir demo/ans
+
 # edit test configuration and check if everything looks right
 vi demo/test.yaml
-
-# edit server configuration and check if everything looks right
-vi config/server.conf
 ```
 
 We are now ready to run the server:
@@ -79,18 +80,47 @@ We are now ready to run the server:
 ./serve.py demo/test.yaml    # run demo test
 ```
 
-Open the browser at `http://127.0.0.1:8080/` and login as user number `0` (administrator) and:
+By default the server listens on all IPs of all network interfaces.
+Open the browser at `http://127.0.0.1:8080/` and login as user number `0` (administrator) and choose any password. Then
 
 1. Authorize students by clicking the checkboxes.
 2. Open a different browser at `http://127.0.0.1:8080/` and login as one of the authorized students. Answer the questions and submit.
 
-The server can be stoped from the terminal with <kbd>^C</kbd>.
+The server can be stoped from the terminal with `^C`.
+
+## Running on port 80
+
+Port 80 is reserved for the root user and and this software _should NOT be run as root_. Instead, the firewall should be configured to forward tcp traffic from port 80 to 8080 where the server is listening. The details depend on the operating system.
+
+### debian:
+
+```.bash
+iptables -t nat -I PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-ports 8080
+```
+
+Explanation:
+    - `-t nat` is the table consulted when a packet creates a new connection.
+    - `-I PREROUTING` inserts rules at the head of the chain.
+    - `-p tcp` selected protocol.
+    - `-s 0/0` source network address/mask.
+    - `-i eth0` interface via which the packet was received.
+    - `--dport 80` destination port.
+    - `-j REDIRECT` what to do when packet matches the rule.
+    - `--to-ports 8080` where to redirect the packets.
+
+### freebsd
+
+Todo...
+
+## Enabling SSL
+
+Todo...
 
 ## Troubleshooting
 
 * The server tries to run `python3`. If only a `python3.5` command is available, you need to set the default python using the OS package manager or manually create a symbolic link:
-    - macOS/macports: sudo port select --set python3 python35
-    - FreeBSD 11: cd /usr/local/bin; ln -s python3.5 python3
+    - macOS/macports: `sudo port select --set python3 python35`
+    - FreeBSD 11: `cd /usr/local/bin; ln -s python3.5 python3`
 
 * If you are getting any `UnicodeEncodeError` type of errors that's because the terminal is not supporting UTF-8. Try running `locale` on the terminal and see if there is any error messages. Solutions:
     - debian: fix it with `sudo dpkg-reconfigure locales`, select your UTF-8 locales and try again.
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