Firewall and technology

Firewalls are blocking many of the useful sites out their we could be utilzing within our classrooms to spark student interest.  If they want us to prepare our students to be better prepared to create and collaborate with on-line tools they need to allow us more reign within the classroom to utilze sites that would allow us to teach the students utilize these types of sites.  Also some teachers, schools, or school districts have more freedom than others on utilzing certain websites, why is this so?  Shouldn't all schools be able to use the same sites so that all students would be prepared in the same way to make them all well rounded candidates for the future?  Firewalls are hindering our abilties to present up-to-date technological opportunities to our students, and that is sad, isn't there something we can do about it?