What is DNS Port and How to allow DNS through Firewall

What is DNS Port and How to allow DNS through Firewall

Find out what DNS Port is. Learn how to open DNS through firewalls and get DNS port numbers. Also, check whether DNS UDP 53 has been used or TCP…

A website’s domain name is its URL address. This URL address is translated via DNS to an IP address. Websites and pages can be searched using either their DNS address or IP address.

Keep in mind that each DNS address is associated with an IP address that is either IPv6/IPv4 and the TCP/IP communication protocol, which is based upon IP addresses, enables DNS addresses to interact.

This is why a DNS port number is used for each domain server name. Domain Name Server consists of a resolver and server, which keeps the information about DNS names and their IP addresses. Resolver, on the other hand, is based upon DNS Client, which asks for server information.

What is DNS Port?

To obtain a Domain Name, a DNS port is used. This interacts with the client device to communicate it to the DNS server. The most commonly used DNS port is UDP 53. It has a maximum of 512 bytes query packets but is not sufficient for large transmissions.

TCP 53 will be used later if transmission bytes exceed 512 bytes. This TCP 53 is frequently used for zone transfers.

To help humans forget their IP addresses, a domain name server is shown. You can use the domain name to search any URL that backward links to the DNS server.

How to allow DNS through the firewall

If you are trying to access an internal network, you must allow outbound traffic on UDP port 53 and TCP port 53 to a trusted DNS Server Name. If there is a firewall, you will need to configure it so that UDP 53 is allowed from clients. You can also restrict TCP 53 to trusted DNS servers from which your zone transfers are to be made.

Zone transfers are the replication of DNS records between DNS servers. They use TCP 53 to communicate. This is the fastest method to replicate a DNS database from one server to another using the query type AXFR.

Domain Name Server consists of mapping IP addresses to Domain Name. It works as though a particular DNS server can’t find an IP address for a domain. Instead, it asks another DNS server to obtain the correct IP mapping.


Domain Name Server used the UDP port to name queries and the TCP port to a zone transfer. At the same time, UDP 53 can be used to transfer small data while TCP is used for large data exchange.

How do I get my DNS Port Number?

To determine the DNS port number for your device, enter HTTP:// into your URL bar. In most cases, the port number will be with URL link port 5000, which is basically a DNS 53 port.

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