What is DNS over TLS (DoT)? – GreenCloud

DNS over TLS protects Internet Service Providers (ISPs) from spying on users. Does SSL no longer do this? Kind of. An SSL certificate facilitates an encrypted connection between a client's browser and a website's server. This means that all communication and activities are hidden during the connection. But the ISP can still see what website you're on. Although it shouldn't be like this, there is a way for your ISP not to even see what website you're visiting. This is called DNS over TLS.

What is DNS over TLS (DoT)?

DNS over TLS (DoT) is a protocol for encrypted transmission of DNS (Domain Name System) queries. On the Internet, name resolution is usually transmitted unencrypted via UDP. However, with DoT, assigning domains and associated IP addresses are encrypted using the Transport Layer Security (TLS) protocol. This protects the transmission from interception, manipulation and man-in-the-middle attacks.

How does DoT work?

The Transport Layer Security protocol (TLS) operates at the highest level of the TCP/IP protocol stack and is thus a stable component of the Internet and many other networks. The protocol is best known as HTTPS. TLS secures client-to-web server transfers and is expected to make communications within DNS more secure in the future.

Data exchange with DNS over TLS takes place over a simple TCP connection and an encrypted channel using a separate Port 853, which is specifically designed for the exchange of domain data. Only two participants of this communication can decrypt and process the data. Therefore, a man-in-the-middle attack is not possible because the attacker cannot process the data.

However, the technology must be supported on the server and client side. Several providers on the Internet offer appropriate DNS servers. Older laptops or desktop computers may require a software upgrade before DNS over TLS can be used. Corresponding solutions are available for Windows and Linux. Smartphones running the latest Android version can now use DNS over TLS.

Advantages of implementing DNS over TLS

Implementing DNS over TLS offers several benefits, including improved privacy and security. By encrypting DNS queries and responses, this protocol helps protect sensitive data from being intercepted or modified by malicious parties.

Enhanced Privacy and Security

One of the main advantages of implementing DNS over TLS is the improved privacy it provides. Traditional DNS queries are sent in clear text, meaning that anyone with access to the network can potentially intercept and see this information. This poses a significant risk, as it allows attackers to track users' online activities, track their browsing habits, and even inject malicious content into their web traffic.

With DNS over TLS, all DNS requests and responses are encrypted using the Transport Layer Security (TLS) protocol. This ensures that only the intended recipient can decrypt and interpret the data, effectively preventing eavesdropping or unauthorized access to sensitive information. By protecting users' privacy in this way, DNS over TLS helps create a more secure online environment.

Potential Performance Impact

While the improved privacy and security offered by DNS over TLS is undoubtedly valuable, it is important to consider the potential performance impacts when implementing this protocol. Encrypting DNS traffic adds an additional layer of processing overhead that can introduce latency and affect overall network performance.

The additional encryption and decryption processes required for each DNS query can lead to slightly slower response times compared to traditional unencrypted DNS. However, advances in hardware acceleration techniques and optimized software implementations have significantly reduced these performance concerns in recent years.

It should be noted that performance impact may vary depending on various factors such as network infrastructure, server capabilities, and client devices. In some cases, the difference may be insignificant or invisible to end users. However, organizations should carefully evaluate and thoroughly test their specific requirements before deploying DNS over TLS on a large scale.

Disadvantages of DNS compared to TLS

Because DoT runs specifically on TCP port 853, it is relatively easy to block the protocol through port filters or firewalls. In such a case, connecting to a particular website requires falling back to regular, “secure” DNS or one of the other encryption methods. Additionally, encryption creates an overhead that results in measurable performance losses.

The result

In conclusion, while implementing DNS over TLS provides improved privacy and security benefits, organizations should weigh these benefits against potential performance impacts, compliance issues, reliance on trusted resolvers, and regulatory considerations before making a decision. It is important for IT professionals, network administrators, and website owners to carefully evaluate their specific needs and infrastructure to determine whether implementing DNS over TLS is the right choice for them.