ISP Blocking Ports

[guitars4god7]

I recently installed ISPconfig 3 on a Ubuntu 10.04 server. Come to find out after setting up my webserver that port 80 is blocked by my isp. Now normally I would just change the /etc/apache2/conf.port file to listen on say port 81 but I'm not sure how that will effect ispconfig since it uses multiple vhosts and I haven't dealt with that before. Are there any other files that need to be edited or will just changing the apache listening port do it?

Or, even better, is it possible to set up some sort of redirect so that when I type in a website I am hosting on the outside (using port) that it redirects on the webserver to port 81. (sorry if this has been discussed before. I did some searches and could not find any relevant information.)

Thanks,
Chance

[falko]

You could set up a proxy, maybe with Squid, lighttpd, nginx, etc. that listens on port 81 and forwards all requests to Apache on port 80.