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. The TCP protocol should not be used for queries as it gives a lot of information, which is useful to attackers.

TCP port 25 — SMTP (Simple Mail Transfer Protocol) TCP and UDP port 53 — DNS (Domain Name System) TCP port 443 — HTTP (Hypertext Transport Protocol) and HTTPS (HTTP over SSL) TCP port 110 — POP3 (Post Office Protocol version 3) TCP and UDP port 135 — Windows RPC. TCP and UDP ports 137–139 — Windows NetBIOS over TCP/IP. What ports are required for Tenable products? Apr 16, 2020 What Is DNS Server Or Protocol Port Number? – POFTUT One of the used DNS port is TCP Port 53. TCP provides stability over DNS resolutions process. With TCP 53 there will be no data loss over network transmission which makes DNS transaction more stable. But this will create some overhead for the server and client because of the TCP behavior.

[SOLVED] Why is port 53/tcp open?

GRC | Port Authority, for Internet Port 20 The connection with the FTP server's port 20 is the second connection created during an FTP session, the first one being to the server's port 21. See the brief discussion below for additional information, and the detailed information on the port 21 page for much more. Related Ports: 21:

Remote Control. To use Configuration Manager remote control, allow the following port: Inbound: TCP Port 2701; Remote Assistance and Remote Desktop. To initiate Remote Assistance from the Configuration Manager console, add the custom program Helpsvc.exe and the inbound custom port TCP 135 to the list of permitted programs and services in Windows Firewall on the client computer.

TCP/IP Ports and Protocols - Pearson IT Certification One of the many fundamental things to know as a network engineer is the function and port number used by a number of common services as well as many that are typically implemented during the course of a network engineer’s career. This article takes a look at these protocols, provides a basic description of their function and lists the port numbers that they are commonly associated with. List of Well-Known TCP Port Numbers - Webopedia Reference Nov 02, 2017 What is DNS? – Introduction to DNS - AWS A DNS service such as Amazon Route 53 is a globally distributed service that translates human readable names like into the numeric IP addresses like that computers use to connect to each other. The Internet’s DNS system works much like a phone book by managing the mapping between names and numbers. Top 20 and 200 most scanned ports in the cybersecurity