2019-10-16 · FTP itself uses the TCP transport protocol exclusively, or in other words, it never uses UDP for its transport needs. Typically an application layer protocol will use one or the other. One notable exception to that is DNS or Domain Name System. FTP also is odd in the fact that it uses two ports to accomplish its task.
How does the DNS protocol switch from UDP to TCP? 2020-5-27 · All I keep hearing is "if the answer is too long, DNS will use TCP". This does not explain how it happens though. So here's the situation: DNS client asks for resolution of a record using UDP. The record is too long for UDP: server answers with specific opcode, to have client switch to TCP; server doesn't answer at all, and client re-tries over TCP TCP/UDP 常用端口列表 - 尘尘test - 博客园 2018-5-30 · 53/TCP,UDP DNS （域名服务系统） 官方 56/TCP,UDP 远程访问协议 官方 57/TCP MTP，邮件传输协议 67/UDP BOOTP（BootStrap协议）服务；同时用于动态主机设置协议 官方 68/UDP Is FTP a TCP or UDP protocol? | AnswersDrive 2019-10-16 · FTP itself uses the TCP transport protocol exclusively, or in other words, it never uses UDP for its transport needs. Typically an application layer protocol will use one or the other. One notable exception to that is DNS or Domain Name System. FTP also is odd in the fact that it uses two ports to accomplish its task.
May 22, 2019 · The idea is to get DNS server operators to update their server software and configurations and ensure their servers can handle DNS queries received as either UDP or TCP packets. DNS Flag Day 2019
Normally, ordinary queries use UDP, and zone transfers use TCP. However, DNS limits UDP queries and responses to about 500 bytes. If a response would be larger than that, the server sends back up to 500 bytes and sets the "truncated" flag. The client is then supposed to perform the same query again using TCP, which is almost unlimited in the User Datagram Protocol (UDP) ìEach UDP message is self-contained and complete ìEach time you read from a UDP socket, you get a complete message as sent by the sender ìThat is, assuming it wasn’t lost in transit! ìThink of UDP sockets as putting a stamp on a letter and sticking it in the mail ìNo need to establish a connection first
Why DNS Works On Both TCP and UDP - TechGenix
UDP is mainly used for online streaming and downloading. TCP is more reliable but a little slower than UDP and usually used for web browsing. You can watch our video for a more detailed explanation: NSLookup, how to set to TCP from UDP? 2016-8-19 · The Transmission Control Protocol (TCP) is used when the response data size exceeds 512 bytes, or for tasks such as zone transfers. Some resolver implementations use TCP for all queries. I suggest you trust NSLookup and other applications to be smart enough to know how they should behave. 为什么 DNS 会使用 UDP 协议，假如使用 TCP 协议 … 2020-5-11 · DNS 的发展史，1987 年的 RFC1034 和 RFC1035 定义了最初版本的 DNS 协议，刚被设计出来的 DNS 就会同时使用 UDP 和 TCP 协议，对于绝大多数的 DNS 查询来说都会使用 UDP 数据报进行传输，TCP 协议只会在区域传输的场景中使用，其中 UDP 通过nslookup的-vc参数强制使用tcp解析域名解 … DNS的问题，已经有很多讨论了 在网上有人介绍，通过tcp协议解析域名，可以获得正确的IP 但Windows默认是udp解析域名，而且无法设置成通过tcp协议解析域名。有人想办法通过修改dnsapi.dll实现tcp方式解析域名。 前些天看到网上有介绍使用nslookup -vc的