If you're wondering whether or not a Skype-based proxy can defend against Distributed Denial of Service attacks or DDoS attacks, then the short answer is yes.
If changing your IP address (or your MAC address) and purchasing web proxy services can help you elude the nefarious machinations of those who've decided to target you with their DDoS attacks and whatnot.
With that said, here's how you setup your own Skype Proxy in order to avoid getting overwhelmed by a flood of tiny yet resource-hogging packets from different IP addresses designed to cripple your system and deny you access to the Internet.
First, you should go to the HideMyAss.com proxy list then match your settings to the proxy you've chosen.
You should pick a server and go with whichever is fastest or closest to your region.
You should prepare for possible fallbacks in case other servers are overloaded (you're not the only one who wants to make use of proxies or has problems regarding DDoS attacks).
You should take note that your Skype doesn't usually utilize the proxy you've setup unless it's blocked from a direct connection.
Therefore, in order to ensure your Skype uses the proxy, you should force it to do so through manipulation of registry settings.
After you've put in the proxy information, the configuration should generate a registry file that you can merge with your existing Windows registry.
The configuration produced registry file is useful in two ways. First, it comes with a key that will help you automatically remove your settings for proxy if you wish to not make use of them anymore.
Second, it's as easy to setup as it is to remove as long as you have a backup of your registry files on hand.
At any rate, when everything is said and done, Skype will use the proxy as soon as the altered registry files ensure that its attempt at direct connection will fail (via the "empty string = unset" configuration contained within the reconfigured registry file).
Don't forget to indicate which proxy to connect to in your Advanced Connection settings.
You might be wondering why you should bother configuring your Skype in order to avoid getting attacked with DDoS.
The answer is simple.
Most hackers or even script kiddies will make use of your known Skype address to procure your IP no matter how many times you change it, so the best course of action to avoid getting DDoS is to have your Skype make use of your proxy service as well.
Depending on how advanced your knowledge is in configuring proxies for Skype, you could force the program to use HTTPS or SOCKS5 proxies as well.