I am trying to learn Django (a python framework for developing web) in docker container recently. After running the docker with port redirect

sudo docker run -p 8000 -t -i centos/django /bin/bash
#in the docker now
cd mysite
python manage.py runserver

The output of Django server is

System check identified no issues (0 silenced).
September 24, 2014 - 08:52:05
Django version 1.7, using settings 'oddjobs.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CONTROL-C.

Then I use command sudo docker ps to find out the port number for host machine:

CONTAINER ID        IMAGE                COMMAND             CREATED             STATUS              PORTS                     NAMES
08d01206d676        centos/oddjobs:run   "/bin/bash"         About an hour ago   Up About an hour    0.0.0.0:49198->8000/tcp   kickass_pare

but when using curl 127.0.0.1:49198 in host machine it just report “Connection Refused”
After searching in google, I only find one article which seems useful for me. But my problem is still there after I follow its steps for solution. With no choice, I have to read the documents of docker carefully and do my experiment step by step.
First, I run a nc-server in docker:

sudo docker run -p 8000 -t -i centos/django /bin/bash
#in the docker now
nc -l 8000
#listening on port 8000

Then using nc 127.0.0.1 8000 in host. It failed too. Why can’t nc client connect to server in docker even I followed the document of docker?After running netstat in docker, I find out the answer: my centos image is centos7 and the ‘nc’ in it will listen on ipv6 address by default. If anyone want to listen on ipv4 address, it should type in

nc -l 8000 -4

Now, the nc client could connect to server now.
But how to run Django server in ipv4 address? This article tells me the way. Now, it seems everything is ok. I start Django again with python manage.py runserver 127.0.0.1:8000 but it still could not be connected with nc client in host. Oh, the ip “127.0.0.1” and “0.0.0.0” is very different so I should run Django like:

python manage.py 0.0.0.0:8000

The browser in host could access the Django example site now.