Are you really bugged by the need to keep changing your browser proxy setting to access blocked sites ?FoxyProxy is the answer to all your proxy woes.
If you are using a proxy proxy.com to access all sites running on port 7777 then do the following :
1. Add proxy.com as proxy
2. Then for that proxy add a pattern like http://*:7777
3. Select “use proxies based on pattern”
Bingo, now all http access to port 7777 will be routed through proxy.com. If there is redirection involved, please add both the url patterns (the redirected to and redirected from) to that particular proxy.