A Proxy Server accepts a client request, makes a separate request on behalf of the client and then returns the response to the client. It is generally used to provide a centralised point of access to the internet. A proxy can also provide additional filtering, caching and security.
The answer to the question is Yes. If you can access the Internet when using Internet Explorer without the need to specify an additional username and password, then there shouldn't be any problems. The only known issue is that BACS.IP does not specify authentication details other than the Windows security context (the currently logged on user). This means that if a Proxy Server cannot be configured to allow access either by application name, Windows username or IP address/hostname, then access will not be allowed. It would be very unusual for a Proxy Server not to support authentication by one or more of these methods.