Hole Punching: To Do Or Not To Do
Hole punching technique is nothing new. It is as old as the firewalls through which it punches hole. But due to the huge popularity of Skype which does hole punching to make VoIP work even when behind firewalls and due to the apparent inability of network administrators to block them, there is a new wave of articles on this topic. Slashdot covered one such article . After reading the comments there it became clear that many don't really understand how protocols like TCP and UDP work or why hole punching works. Hole punching head-ache at office: Hype is that network administrators will have a lot of headache managing the bandwidth consumed by all these p2p applications that punch holes and "illegally" transfer data. But that isn't the case in reality. Network administrators have a variety of options at their disposal. Like in case of Skype, they can always block the various Skype central site IP addresses. Also, an advanced stateful firewall like IPTables in Linux c