Mar 02, 2011 · UDP's semanatics are faster for small (<= 1MTU) transactions since there is no connection state and no handshaking. Further, at the time DNS was designed, TCP was not considered 'scalable' since each TCP connection required its own file descriptor and computers at the time struggled with even 64 file descriptors per process.
Port 53 (tcp/udp) :: SpeedGuide tcp,udp: DNS: DNS (Domain Name Service) used for domain name resolution. There are some attacks that target vulnerabilities within DNS servers. Cisco Webex Teams services uses these ports: 443,444,5004 TCP 53, 123, 5004, 33434-33598 UDP (SIP calls) Xbox 360 (Live) ports: 3074 TCP/UDP, 53 TCP/UDP, 80 TCP, 88 UDP DNS Capture: UDP, TCP, IP-Fragmentation, EDNS, ECS, Cookie It’s not always this simple DNS thing such as “single query – single answer, both via UDP”. Sometimes you have some more options or bigger messages that look and behave differently on the network. For example: IP fragmentation for larger DNS answers that do not fit into a single UDP datagram (hopefully not after the DNS flag day 2020 anymore ), or DNS via TCP, or some newer options within the EDNS … Why is UDP used for DNS instead of TCP? Isn't TCP supposed Mar 02, 2011 domain name system - Do DNS queries always travel over UDP
Port 53 (tcp/udp) :: SpeedGuide
We have just covered the most basics of networks, but, of course, there is almost a dozen of technologies, which are worth to look at. Google VXLAN on your own, learn TCP and UDP (and figure out which one when to use), look at IMCP. You will encounter new terms constantly, but, as always, the most important thing is to learn the fundamentals. Jul 17, 2020 · Application of UDP. UDP method is largely used by time-sensitive applications as well as by servers that answer small queries from a larger client base. UDP is compatible with packet broadcasts for sending all over the network and for multicasting sending. It is also used in Domain Name System, Voice over IP, and online games. Advantage of TCP Section 6.1.3.2 of [RFC1123] states: DNS resolvers and recursive servers MUST support UDP, and SHOULD support TCP, for sending (non-zone-transfer) queries. However, some implementors have taken the text quoted above to mean that TCP support is an optional feature of the DNS protocol. Feb 18, 2018 · By the end of this course, you’ll be able to: - describe computer networks in terms of a five-layer model. - understand all of the standard protocols involved with TCP/IP communications. - grasp
Oct 26, 2013 · Hi, Well the UDP connections don't really have a state to track like TCP. I guess one of the most common things to track with regards UDP on the ASA firewall might be DNS inspection and things related to DNS queries.
tcp,udp: DNS: DNS (Domain Name Service) used for domain name resolution. There are some attacks that target vulnerabilities within DNS servers. Cisco Webex Teams services uses these ports: 443,444,5004 TCP 53, 123, 5004, 33434-33598 UDP (SIP calls) Xbox 360 (Live) ports: 3074 TCP/UDP, 53 TCP/UDP, 80 TCP, 88 UDP Mar 02, 2011 · UDP's semanatics are faster for small (<= 1MTU) transactions since there is no connection state and no handshaking. Further, at the time DNS was designed, TCP was not considered 'scalable' since each TCP connection required its own file descriptor and computers at the time struggled with even 64 file descriptors per process. Mar 31, 2007 · It is stated the DNS can use both TCP and UDP. The DNS resolver uses UDP. My question is: when is TCP used for DNS? (exept zone transfer between servers). From the client point of view is there a moment when TCP is used? Thanks A part of the DNS service is that it uses UDP, and Azure Firewall uses SNAT for address translation from every internal source, resulting in every UDP request from one IP to an external provider (8.8.8.8, 8.8.4.4, 1.1.1.1 etc.) will use one port out of the 65.000 available in the TCP protocol for that unique destination. We have just covered the most basics of networks, but, of course, there is almost a dozen of technologies, which are worth to look at. Google VXLAN on your own, learn TCP and UDP (and figure out which one when to use), look at IMCP. You will encounter new terms constantly, but, as always, the most important thing is to learn the fundamentals.