I know this is going to come across as egg sucking CPD ... but when you are testing your school connection remember a) to do it when you don't have 3 classes all trying to use youtube, b) you understand you are testing your connection usually as it goes via a proxy which does a heck of a lot more checking than a commercial provider does and c) that your LAN is not compromised in any way (ie you are not doing it over cascaded hubs!).

Sorry if it sounds a little tetchy, but all the above have been issues this year.