Is UDP hole punching safe?

Is UDP hole punching safe?

“does the dual external IP addresses mean that UDP hole punching will never be reliable?” UDP hole punching is never reliable in the first place.

How does UDP hole punching work?

UDP hole punching is a method for establishing bidirectional UDP connections between Internet hosts in private networks using network address translators. After that the NAT device has a record of having sent a packet to the other machine, and will let any packets coming from this IP address and port number through.

How do you test a UDP hole punch?

How to experience UDP hole punching using Ncat under Linux?

1. Open port 1234/UDP on host A and port 12345/UDP on host B’s firewall (I’m still behind NAT, but if the packet reaches me, at least kernel won’t discard it)
2. sudo ncat -u -p 1234 B 12345 on host A, then try sending a packet to punch a hole.

Does UDP have keep alive?

NAT keepalive is a feature that sends very tiny data packets, called UDP packets, from a VoIP phone to the router to show that the port is still in use. The phone will send these small packets at timed intervals set by your phone or your phone system.

How does stun ice turn work?

The ICE algorithm in each browser takes a candidate IP/port pair from the list it received in the other party’s SDP, and sends it a STUN request. If a response comes back from the other browser, the originating browser considers the check successful and will mark that IP/port pair as a valid ICE candidate.

How UDP is different from TCP?

TCP is a connection-oriented protocol, whereas UDP is a connectionless protocol. A key difference between TCP and UDP is speed, as TCP is comparatively slower than UDP. Overall, UDP is a much faster, simpler, and efficient protocol, however, retransmission of lost data packets is only possible with TCP.

Can UDP be bidirectional?

They are TCP or Transmission Control Protocol and UDP or User Datagram Protocol. TCP is connection oriented – once a connection is established, data can be sent bidirectional. UDP is a simpler, connectionless Internet protocol.

Why is NAT bad for P2P?

Abstract: Network Address Translation (NAT) causes well-known difficulties for peer-to-peer (P2P) communication, since the peers involved may not be reachable at any globally valid IP address.

Is UDP still used?

UDP is commonly used for applications that are “lossy” (can handle some packet loss), such as streaming audio and video. It is also used for query-response applications, such as DNS queries.

How is UDP hole punching implemented in C #?

UDP hole punching implementation in C#. UDP hole punching is a method that is used to establish connectivity between two hosts that are behind a NAT (router) without the need of having the clients port forward specific ports.

Which is an example of hole punching in C?

This repository contains a simple example of UDP hole punching in C. It compiles to two binaries, a server that relays client information and a simple client that ping-pongs data to and from another instance of itself.

Can a UDP hole punch work with symmetric NAT?

UDP hole punching will not work with symmetric NAT devices (also known as bi-directional NAT) which tend to be found in large corporate networks.

Is it possible to hole punch the Nat?

However when A sends an outbound packet, then it is possible that while traversing the NAT, the NAT changes the port number of A (often called port randomization). This makes UDP hole punching almost impossible. The IP address is also rewritten to resemble the IP address of the NAT.