2017年1月19日 · ネットワーク系の用語で TCP/IP という表記はよく目にしますが UDP/IP という表記はあまり見ません。 TCP も UDP も、どちらも IP ネットワーク上で実装されているプロトコルなのに奇妙に思います。 なぜ TCP だけ TCP/IP と表記しがちで UDP は UDP/IP と表記しないのでしょうか？

2011年9月18日 · Once a packet reaches a host using its IP address, the packet needs to be given to one of the applications on this machine. To determine which application should get the packet, it needs demultiplexing logic, which is based on ports. UDP has port information which is used by IP to deliver the packet to appropriate application.

2011年6月16日 · Regarding the broadcast IP addresses, both addresses are broadcast addresses but the limited broadcast address (which is 255.255.255.255) won't be forwarded by routers. It is better to use the subnet-directed broadcast address (192.168.2.255).

A single IP_ADDRANY-bound UDP server should be able to appear to respond on the same dynamically-assigned IP address a packet is received on. Luckily, there is another way. Depending on your system's support you can make use of the IP_PKTINFO socket options to set or receive ancillary data about a message.

Basically I want to create a protocol where I send a udp packet and then I expect a response. Just like the HTTP protocol for every request there is a response. This code works if the server is on a different computer. There might be the case where the server and client are on the same computer though. Here is the server:

2012年5月22日 · In regards to why ports are specified during a multicast subscription - it's because multicast IP is just that - IP only. "ports" are a property of the upper protocols (UDP and TCP). You can read more about how multicast IP addresses map to multicast ethernet addresses at various sites. The Wikipedia article is about as good as it gets:

2013年7月3日 · UDP, on the other hand, is a packet-oriented protocol where the application such as Java class java.net.DatagramPacket; java.net.DatagramPacket; import java.net.DatagramsSocket creates a packet first before talking to UDP, and the packet is sent out with additional information by UDP/IP protocols to the server side.

2019年4月10日 · Unlike a TCP socket, a UDP socket can communicate with multiple remote parties at a time, where sendto() specifies a destination ip/port, and recvfrom() reports a sender's ip/port. I understand why IP Helper can't do the job (udp is connectionless and need to capture packet) but I found nothing concrete how to accomplish that.

2009年11月29日 · Client emits UDP packet. Router passes UDP packet to the Internet. Router remembers that client sent a UDP packet to server, and establishes a mapping in its memory. Server sends a UDP packet, probably on the same port. Router receives packet, and checks mapping to find client talked to server recently. Router passes packet to client.

I am trying to write a program to send UDP packets, as in https://wiki.python.org/moin/UdpCommunication The code appears to be in Python 2: import socket UDP_IP ...