What is the protocol number of DNS?
What is the protocol number of DNS?
port 53
DNS uses the User Datagram Protocol (UDP) on port 53 to serve DNS queries. UDP is preferred because it is fast and has low overhead. A DNS query is a single UDP request from the DNS client followed by a single UDP reply from the server.
How many protocol numbers are there?
The port numbers from 49152 to 65535 are the “private ports.” Private port numbers are available for any use. Port numbers are not unique between transport layer protocols; the numbers are unique only within a specific transport protocol. In other words, TCP and UDP can and do assign the same port numbers.
What is the protocol number for SSH?
Service Name and Transport Protocol Port Number Registry
| Service Name | Port Number | Transport Protocol |
|---|---|---|
| tl1-ssh | 6252 | udp |
| ssh-mgmt | 17235 | tcp |
| ssh-mgmt | 17235 | udp |
| sftp-ssh |
What is TCP 53 used for?
The DNS uses TCP Port 53 for zone transfers, for maintaining coherence between the DNS database and the server. The UDP protocol is used when a client sends a query to the DNS server.
What is a clinical trial protocol number?
Definition: The Clinical Trial Protocol ID (0012,0020) is the number or character sequence used by the Clinical Trial Sponsor to uniquely identify the investigational protocol in which the subject has been enrolled. Identifier for the noted protocol.
Why is protocol number used?
The protocol number is used by the the layer-3 protocol (IPv4 or IPv6) to determine to which layer-4 protocol in the network stack it should send the payload of the packet. A port number is an address for some layer-4 protocols (TCP or UDP).
What is port No 25?
Port 25 is the original standard email SMTP port and the oldest, since it first debuted in 1982. Today, the Internet Assigned Numbers Authority (IANA), the group responsible for maintaining the internet addressing scheme, still recognizes port 25 as the standard, default SMTP port.
What port number is 21?
Port 21 controls the FTP session The File Transfer Protocol provides a framework to transfer information between two networked computers, much like Hypertext Transfer Protocol does through a web browser. FTP, however, operates on two different Transmission Control Protocol ports: 20 and 21.