UDP cannot be connected, what is UDP connection?

UDP is the abbreviation of User Datagram Protocol, Chinese name is User Datagram Protocol, is a connectionless transport layer protocol in the OSI (Open System Interconnection) reference model, providing transaction-oriented simple and unreliable information transmission services, IETF RFC 768 is the formal specification of UDP. The protocol number of the UDP packet is 17.

The UDP socket list changes.

After using the two socket options, so reuseaddr and so reuseport, the kernel will find the location of one of the sockets on the machine that has the same destination IP address according to the 4-tuple of the UDP packet, and then use the socket in this position as the socket that receives the data. To ensure that UDP packets from the same client endpoint are always processed by the same socket, you need to ensure that the position of the socket in the entire socket linked list cannot be changed.

However, if a socket hangs in the middle of the socket linked list, it will cause the socket linked list to be reordered, which will cause problems. So the basic solution is not to close the UDP socket during the entire service (of course, you can also close all the UDP sockets and create a new batch from scratch). To ensure this, we need that all UDP socket creation and closure are managed by a master, and that the worker process is only responsible for handling the network IO tasks, for which we need the socket to be created with the cloexec flag (sock cloexec).

Hello, glad to answer for you. It can be judged and solved from the following aspects: 1. Pin brother check whether the wireless network card settings are correct

IP, mask, gateway, and DNS can generally be obtained automatically. Whether it can successfully connect to the router and obtain the correct IP, DNS, etc. 2. Log in to the router and check whether the external network connection is successful.

If it is unsuccessful, look at the WAN settings, and set the Internet mode: dynamic IP, static IP, PPPoE. If it is pppoe, check whether the password is correct, and the account is duplicated.

3. If the connection to the network has been successful, it is still impossible to access the Internet. Ping the DNS server can't get through (if ping is allowed). If not, check the router DHCP gateway settings, if it is through, it still can't open the web page, check whether the router DNS has been tampered with, just in case you can manually set the DNS of the local wireless network card to the operator's check router's other Internet restrictions and other settings, if you can't find it, then restore the default settings.

1.The direct cause of the problem: Generally, the UDP protocol in the data center is disabled by default.

And when you use it as a game server, you often can't connect to the game after installing it. The various indicators of the machine are normal, and even the login device shows that the connection is normal. But it's better to log in than to go into the game.

The main culprit is that the UDP protocol is not opened. Game. What is and what business needs to open UDP?

UDP --- User Datagram Protocol, is a simple datagram-oriented transport layer protocol. UDP doesn't provide reliability, it just does. 3.

Why is UDP disabled by default in the data center? Speaking of which, it is to consider the security of UDP, and it is also a disadvantage of its slag.

It may be that some of your software blocks the UDP port, similar to firewall software, you better check the settings to see.

After yesterday's update, many students have the problem of UDP connection failure, and the phenomenon is that 10 seconds after selecting the channel, the left and right games report UDP errors, and then exit.

The problem mostly occurs in the case of routed NAT, in fact, many people can play normally after skipping NAT. But after all, Internet cafes and company rental groups will not serve one person, and my own problem is more serious, and the problem of skipping NAT is still the same. Seeing that TX is not doing things effectively, and it is not the right time for XE to flood, it is estimated that TX has no time to take care of this matter, so he can only find a way to solve it by himself.

The convenient way to solve this problem is to turn off the modem or router and turn it back on (that is, restart the network connection) after 2-3 UDP connection errors in a row, and then everything will be back to normal.

The easiest way is to restart the machine and press F8, enter the safe mode, and restore the system to the initial data, the reason is because you use antivirus software to block some ports, and the data will be written to the registry after the shielding operation, if you don't do any raw system backup, it is difficult to return, the only way is to restore the system to the case without installing any antivirus defense, it is recommended to install antivirus software first, and then install application software, Note that after installing the antivirus software, remember not to do any optimization and restrict port operations, otherwise similar problems will occur.

If the other party is inside another LAN, then unless you have one on the Internet"Really"The IP server acts as a transit and records the real IP ports of both parties, just like the OICQ registration server, otherwise it is impossible to connect.

If the other party has"Really"ip, that can be connected directly.

If the other person is also inside the same LAN as you, you can also connect directly.

You can: remoteip="..."

btw: ping is not successful, may not be able to get out **, our company ping is not working anywhere -- the network management has blocked the ping :(