DNS Port Usage – How to allow DNS through Firewall ?

Firewalls become very important when it comes to the restriction and control of the internet. The internet traffic that is being sent between the web and the network of the company is handled by firewalls. Domain Name System is an internet protocol that converts human-readable names into their IP addresses. It also helps in changing the IP addresses back to their names thus providing remember-worthy names for any or every internet-based service for instance email.

Through this enhancement, the LAN’s security policy is enabled. It results in enabling the data that reach out to the network. When an individual attempts to connect to a website. The computer will connect it to the server of the DNS by following up with the IP address for the entered website. Just in case, DNS has been disabled on the firewall, connection to the Web addresses will not be possible.

DNS Port

To get a specific domain name, the DNS port number plays an important role. It helps in the interaction with the client device. Hence following up with the communication to the DNS server. This is the place where the most frequently DNS Port used is UDP 53. The specific DNS Port has the highest size of 512 bytes query packets and is not large enough for transmission.

Later TCP 53 was used if the situation of transmission bytes is increased than 512 bytes. This TCP 53 has been regularly for zone transfers. The domain name server is pictured in a way that humans can eliminate the IP address. After this, the domain name can be used to search any URL. Furthermore, the backward process will connect to the correspondence IP address that is saved in the DNS server.

DNS port

DNS Security

When it comes to the target of network attacks, DNS is becoming a very common and subtle target. It has been determined that every other service as well protocol uses a port number of DNS. It makes DNS a basic target for attackers. Provided that it is considered one of the very dependent protocols. When it comes to stopping the attacks, it will not be as easy as adding the firewall rule. The entire procedure of securing the DNS seems a bit complicated. The sole purpose of DNS is not only to publish information. But it also allows clients to get access to the information.

Allowing DNS through Firewall

Under the situation where you are trying any kind of internal Wifi network. It is mandatory to allow outbound traffic on UDP port number and TCP ports 53. It has to be done towards a trusted DNS server name which is an external one. In any case, where there is a firewall that is being managed by an individual. It is important to allow UDP 53 from the respective clients. In addition to this, it’s also vital to get the other TCP 53 restricted from all other trusted DNS ports servers from where the individual wants to zone transfers.

Zone transfers are a replication of DNS records from one of many DNS servers to another where the TCP 53 is used for communication. This can be also labeled as the fastest way to replicate the DNS database to another server by using AXFR in the form of query type.

In terms of Domain Name Server, it comprises many associations and mapping of the IP addresses with the correspondence Domain Name. When the DNS server is unable to find the respective IP address of a certain domain then it generally asks for a different DNS server so that access to the correct IP for Domain mapping is possible.


Just in case you are wondering,’ what is the port number of DNS?, the TCP port is used by the Domain Name Server for zone transfers along with the UDP port for named inquiries. Meanwhile, UDP 53 is utilized so that any kind of small information can be transferred hence using the TCP to exchange massive amounts of information data.

Getting the DNS Port Number

To obtain the DNS port number of a device, one needs to enter the HTTP:// in the URL bar to solemnly determine the port number In most cases, the Port number will be attached with the URL link in the form of a port 5000 which originally is a DNS port. Thus, these are everything that was there to know regarding DNS and allowing it through the Firewall.

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