I want to be 100% sure that my machine only connects where and when I want it to. If I use a firewall that blocks all UDP and TCP packets but those that I explicitly allow to pass, can I be 100% sure that my machine does not connect anywhere without my approval?
For example, if I did not know about UDP at all and only specified TCP rules on the firewall, I would still be vulnerable to malware and nasty spyware exploiting UDP packets. So technically speaking, is there any other means/protocols apart from UDP and TCP that can be used to communicate with a computer using wired/wireless network connections? Also, can UDP and TCP packets bypass firewalls?
The question has arisen when I installed Little Snitch on my Mac with OS Mavericks and noted that my machine tries to connect to various Apple and third party servers even though I told it that I did not want any info to be collected and sent. Some of the connections were obviously fine (e.g. ntp time syncs), but others were questionable to say the least. I know that hard/software manufacturers potentially can embed backdoors and snitches and so I am trying to figure out how feasible it is in theory (and practice) to have reliable/robust "border control" on my machine.