What is DNS over TLS (DoT)?
DNS over TLS keeps Internet Service Providers (ISPs) from spying on users. Doesn’t SSL already do that? Sort of. An SSL certificate facilitates an encrypted connection between a client’s browser and a website’s server. That means that during the connection all communication and activity are obscured. But, the ISP can still see what website you’re on. It doesn’t have to be that way though, there is a way to keep your ISP from even seeing what website you’re accessing. It’s called DNS over TLS.
What is DNS over TLS (DoT)?
DNS over TLS (DoT) is a protocol for the encrypted transmission of DNS (Domain Name System) queries. Name resolution on the Internet is typically transmitted unencrypted via UDP. With DoT, however, the assignment of domains and the associated IP addresses is 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 fixed component of the Internet and many other networks. The protocol may be best known as HTTPS. TLS secures transfers from the client to the web server and is expected to make communication within DNS more secure in the future.
With DNS over TLS, the data exchange occurs via an encrypted channel using a simple TCP connection and a separate Port 853, which is specifically intended for the exchange of domain information. Only the two participants in this communication can unencrypt and process the data. Therefore, a man-in-the-middle attack is not possible because the attacker cannot process the data.
The technology must, however, be supported on the server and client side. Several providers on the Internet offer appropriate DNS servers. Where older laptops or desktop PCs are in use, the software may need to be upgraded before DNS over TLS can be used. For Windows and Linux, relevant solutions exist. Smartphones running the latest Android version can already use DNS over TLS.
Pros of implementing DNS over TLS
Implementing DNS over TLS offers several advantages, including enhanced privacy and security. By encrypting DNS queries and responses, this protocol helps protect sensitive information from being intercepted or tampered with by malicious actors.
Enhanced Privacy and Security
One of the primary benefits of implementing DNS over TLS is the enhanced privacy it provides. Traditional DNS queries are sent in plaintext, which means that anyone with access to the network can potentially intercept and view this information. This poses a significant risk, as it allows attackers to monitor users’ online activities, track their browsing habits, and even inject malicious content into their web traffic.
With DNS over TLS, all DNS queries 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 enhanced privacy and security offered by DNS over TLS are undoubtedly valuable, it’s important to consider potential performance impacts when implementing this protocol. Encrypting DNS traffic adds an extra layer of processing overhead, which 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, advancements in hardware acceleration techniques and optimized software implementations have significantly mitigated these performance concerns in recent years.
It’s worth noting that the impact on performance may vary depending on various factors such as network infrastructure, server capabilities, and client devices. In some cases, the difference may be negligible or imperceptible to end-users. However, organizations should carefully evaluate their specific requirements and conduct thorough testing before implementing DNS over TLS on a large scale.
The disadvantages of DNS over TLS
Since DoT runs specifically over TCP port 853, the protocol is relatively easy to block via port filters or firewalls. In such a case, a fallback to conventional, “unsecured” DNS or one of the other encryption methods is required to establish a connection to a specific website. Furthermore, the encryption creates an overhead that results in measurable performance losses.
Conclusion
In conclusion, while implementing DNS over TLS provides enhanced privacy and security benefits, organizations should weigh these advantages against potential performance impacts, compatibility challenges, reliance on trusted resolvers, and regulatory considerations before making a decision. It is essential for IT professionals, network administrators, and website owners to carefully evaluate their specific needs and infrastructure to determine if implementing DNS over TLS is the right choice for them.