TCP Communication
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I need to implement TCP hole punching in my application. I tried to google to find any sample implementation but could not get. Please suggest me idea behind TCP hole punhing with example...
try this
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I need to implement TCP hole punching in my application. I tried to google to find any sample implementation but could not get. Please suggest me idea behind TCP hole punhing with example...
UDP/TCP hole punching is Communication between two computers without opening ports, using a third computer to set up the connection UDP/TCP hole punching is NOT a security violation in any way, even though the name suggests it is. Once the hole has been punched in the firewall, only connections from the specified client are accepted through it, it isn't like anyone can get in through the hole. Get the win32 DLL here: http://www.cis.nctu.edu.tw/~gis87577/xDreaming/XSTUNT/index.html[^] It works like this:
A--->proxy --------proxy<---B
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SLet A be the client requesting the connection Let B be the client that is responding to the request Let S be the server that they contact to initiate the connection A sends a connection request to S S responds with B's IP and port info, and sends A's IP and port info to B A sends a UDP/TCP packet to B, which B's router firewall drops but it still punches a hole in A's own firewall where B can connect B sends a UDP/TCP packet to A, that both punches a hole in their own firewall, and reaches A through the hole that they punched in their own firewall A and B can now communicate through their established connection without the help of S All this does is make both A and B's firewalls think that they have initiated the connection, just as it would let packets from a web server through ONLY if the client had initiated the connection to the web server and the packets were expected. This is not a security risk and software that uses this method should not be looked down upon, this is how p2p software like AIM and most VoIP clients initiate connections. TCP hole punching Algorithm Let A and B be the two hosts, each in its own private network; N1 and N2 are the two NAT devices; S is a public server with a well-known globally reachable IP address. A and B each begin a TCP conversation with S; the NAT devices N1 and N2 create TCP translation states and assign temporary external port numbers S relays these port numbers back to A and B A and B contact each others' NAT devices directly on the translated ports; the NAT devices use the previously created translation states and send the packets to A and B The Low TTL is calculated as follow:
Sen
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I need to implement TCP hole punching in my application. I tried to google to find any sample implementation but could not get. Please suggest me idea behind TCP hole punhing with example...
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UDP/TCP hole punching is Communication between two computers without opening ports, using a third computer to set up the connection UDP/TCP hole punching is NOT a security violation in any way, even though the name suggests it is. Once the hole has been punched in the firewall, only connections from the specified client are accepted through it, it isn't like anyone can get in through the hole. Get the win32 DLL here: http://www.cis.nctu.edu.tw/~gis87577/xDreaming/XSTUNT/index.html[^] It works like this:
A--->proxy --------proxy<---B
|
SLet A be the client requesting the connection Let B be the client that is responding to the request Let S be the server that they contact to initiate the connection A sends a connection request to S S responds with B's IP and port info, and sends A's IP and port info to B A sends a UDP/TCP packet to B, which B's router firewall drops but it still punches a hole in A's own firewall where B can connect B sends a UDP/TCP packet to A, that both punches a hole in their own firewall, and reaches A through the hole that they punched in their own firewall A and B can now communicate through their established connection without the help of S All this does is make both A and B's firewalls think that they have initiated the connection, just as it would let packets from a web server through ONLY if the client had initiated the connection to the web server and the packets were expected. This is not a security risk and software that uses this method should not be looked down upon, this is how p2p software like AIM and most VoIP clients initiate connections. TCP hole punching Algorithm Let A and B be the two hosts, each in its own private network; N1 and N2 are the two NAT devices; S is a public server with a well-known globally reachable IP address. A and B each begin a TCP conversation with S; the NAT devices N1 and N2 create TCP translation states and assign temporary external port numbers S relays these port numbers back to A and B A and B contact each others' NAT devices directly on the translated ports; the NAT devices use the previously created translation states and send the packets to A and B The Low TTL is calculated as follow:
Sen
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I need to implement TCP hole punching in my application. I tried to google to find any sample implementation but could not get. Please suggest me idea behind TCP hole punhing with example...
Pretty sure it can be more complicated than the other replies suggest. Presuming a physical connection between two computers exists then the control of that channel will certainly fall under one or more routers and possibly one or more firewalls. If any one of those precludes communication then the linkage will fail. So one must know that all of them exist and be prepared to configure all of them.