Copy and paste the following line into a text file. See also this faq for information on how to use the configuration file.

2mydns.com

# This is configuration file for
# http://www.2mydns.com/
# dynamic DNS service provider
#
# No change is needed in this file
#
# Enter hostname on program complete with domain name

[default]
withpass=0
host=dyn.2mydns.com
port=80
path=/dyn.asp

[requests]
hostname=%HOST%
username=%USER%
password=%PASS%
myip=%IP%

[result]
multilines=0
success=1000
warning=1001