The priority for users behind censoring firewalls is access, not privacy at the browsed site. The following text reflects this. Net censorship in the UAE is quite sophisticated. There are two separate aspects which need to be considered by anyone wanting to communicate freely. The list of censored URLs is updated frequently.
Few packets appear to be filtered in the incoming direction.
A timeout occurs in this case. Attempting to use an external web proxy will mostly fail simply because the proxy port you need to connect to is blocked by the filters. Outgoing packets to these ports are all blocked. Again a timeout occurs. Internet access is generally flaky and slow because of all this stupidity.