If you wish to change the default configurations then follow this steps:
Open terminal type command
$ /usr/local/lib/python<2/3>.x/dist-packages/django/core/management/commands
Now open runserver.py file in nano editor as superuser
$ sudo nano runserver.py
find the 'default_port' variable then you will see the default port no is '8000'. Now you can change it to whatever you want.
Now exit and save the file using "CTRL + X and Y to save the file"
Note: Replace <2/3>.x with your usable version of python