DNS was designed from the start to use both UDP and TCP port 53 1 , where UDP is the default, and fall back to using TCP when communication over UDP is not possible, usually if the packet size is too big fit into a single UDP packet.
What port does the DNS server use?
A DNS server uses the well-known port 53 for all its UDP activities and as the server port for TCP. It uses a random port greater than 1023 for TCP requests. A DNS client uses a random port greater than 1023 for both UDP and TCP.
Which service is port 445?
TCP port 445 is used for direct access to the MS TCP/IP network without requiring a NetBIOS layer. This service is only implemented in newer Windows versions from Windows 2000 and Windows XP. The SMB protocol (Server Message Block) is used, among other things, for file sharing under Windows NT/2K/XP.
What is port 80 used for?
Port 80 is the port number assigned to the commonly used Internet communications protocol, HTTP (Hypertext Transfer Protocol). This is the port through which a computer sends and receives web client-based communications and messages from a web server, and is used to send and receive HTML pages or data.
What is the main purpose of the DNS server?
DNS translates domain names into IP addresses so browsers can load Internet resources. Every device connected to the Internet has a unique IP address that other computers use to find the device. DNS servers eliminate the need for humans to remember IP addresses like 192.168.1.
What types of DNS servers are there?
The three types of DNS servers are:
- DNS stub resolver servers.
- Recursive DNS resolver server.
- Authoritative DNS server.
What service is port 139 for?
Therefore, SMB requires network ports on a computer or server to allow communication with other systems. SMB uses IP port 139 or 445. Port 139: SMB originally ran over NetBIOS using port 139 . NetBIOS is a legacy transport layer that allows Windows computers to communicate with each other on the same network.
What is port 139 used for?
Port 139 is used for file and printer sharing, but is the most dangerous port on the Internet. This is because a user’s hard drive is exposed to hackers.
Are ports 8080 and 80 the same?
No, port 80 and port 8080 are not the same. Ports are used to make connections unique, and range from 0 to 65535, up to 1024 of which are known ports reserved by convention to identify specific types of services on a host. … port 8080 is simply the default second choice for a web server.
How do I know if port 80 is free?
Verifying Port 80 Availability
- From the Windows Start menu, select Run.
- In the Run dialog box, type: cmd .
- Click OK.
- In the command window, type: netstat ano.
- A list of active connections is displayed. …
- Start the Windows Task Manager and select the Processes tab.
- If you don’t see the PID column, choose Choose Columns from the View menu.