{"id":2169,"date":"2026-08-12T08:00:00","date_gmt":"2026-08-12T07:00:00","guid":{"rendered":"https:\/\/ic-services.io\/?p=2169"},"modified":"2026-10-21T14:14:09","modified_gmt":"2026-10-21T13:14:09","slug":"dns-crittografato-doh-li-quali-sono-le-conseguenze","status":"publish","type":"post","link":"https:\/\/ic-services.io\/it\/resources\/blog\/encrypted-dns-doh-dot-li-impact\/","title":{"rendered":"DNS criptato (DoH\/DoT) e il suo impatto sulle capacit\u00e0 di intercettazione legale"},"content":{"rendered":"

The Domain Name System (DNS) has long been one of the most valuable data sources for lawful interception and network intelligence. DNS queries reveal which websites a user visits, which services they access, and which applications they use, even when the rest of the traffic is encrypted. For decades, DNS traffic has been transmitted in plaintext, making it readily accessible to network-level interception. The emergence of encrypted DNS protocols \u2014 DNS over HTTPS (DoH) and DNS over TLS (DoT) \u2014 is fundamentally changing this landscape, with significant implications for capacit\u00e0 di intercettazione legittima<\/a>.<\/p>\n\n\n\n

Questo articolo analizza il funzionamento dei protocolli DoH e DoT, i motivi per cui vengono adottati, il loro impatto sulle intercettazioni legittime e le misure che gli operatori possono adottare per adempiere ai propri obblighi di conformit\u00e0 in un contesto in cui il traffico DNS \u00e8 sempre pi\u00f9 crittografato.<\/p>\n\n\n\n

La sfida del DNS crittografato per gli operatori<\/h2>\n\n\n\n

Traditional DNS resolution uses port 53 (mostly UDP, with TCP for larger responses), transmitting queries and responses in plaintext. Anyone with access to the network path between the user and the DNS resolver \u2014 including the operator, intermediate network elements, and potential eavesdroppers \u2014 can observe the DNS queries and determine which domain names the user is resolving.<\/p>\n\n\n\n

DNS over TLS (DoT), defined in RFC 7858, encrypts DNS traffic by wrapping it in a TLS connection on TCP port 853. The DNS queries and responses are encrypted in transit, preventing observation by intermediaries. However, the use of a dedicated port (853) makes DoT traffic identifiable at the network level \u2014 an observer can determine that DNS resolution is occurring, even though the content of the queries is encrypted. A third protocol, DNS over QUIC (DoQ, RFC 9250), runs on UDP port 853. Oblivious DoH (RFC 9230) additionally hides the user’s IP address from the resolver.<\/p>\n\n\n\n

DNS over HTTPS (DoH), defined in RFC 8484, takes encryption a step further by tunnelling DNS traffic within standard HTTPS connections on port 443 (TCP, or UDP when HTTP\/3 over QUIC is used). Because DoH uses ordinary HTTPS on port 443, its content cannot be separated from web traffic, although connections to well-known public resolvers can still be recognised by their addresses. DoH effectively hides DNS resolution within the vast volume of encrypted web traffic that traverses modern networks.<\/p>\n\n\n\n

Entrambi i protocolli sono stati progettati per proteggere la privacy degli utenti impedendo agli intermediari di rete di monitorare le query DNS. I principali produttori di browser \u2014 tra cui Mozilla Firefox e Google Chrome \u2014 hanno implementato il supporto per il DoH, e alcuni sistemi operativi ora supportano nativamente sia il DoH che il DoT. L'adozione del DNS crittografato sta accelerando, spinta dalla difesa della privacy, dalle impostazioni predefinite dei browser e dalla tendenza pi\u00f9 ampia verso la crittografia di tutto il traffico di rete.<\/p>\n\n\n\n

L'impatto sull'intercettazione legale<\/h2>\n\n\n\n

The encryption of DNS traffic has a direct and significant impact on lawful interception capabilities. Plaintext DNS queries have traditionally been visible to investigators inside the content of communication (CC): the IP copy of the target’s traffic includes every DNS packet, providing a detailed record of the target’s online activity. When a target visits a website, sends an email, or uses an application, the corresponding DNS queries reveal the domain names involved, even when the content of the communication is encrypted.<\/p>\n\n\n\n

Con DoH e DoT, gli operatori non possono pi\u00f9 monitorare le query DNS a livello di rete se il dispositivo di destinazione \u00e8 configurato per utilizzare un resolver DNS crittografato non gestito dall\u2019operatore. Il processo di risoluzione DNS \u00e8 crittografato end-to-end tra il dispositivo e il resolver, e le apparecchiature di rete dell\u2019operatore non possono decrittografare le query senza avere accesso alle chiavi di sessione TLS.<\/p>\n\n\n\n

This loss of DNS visibility affects real-time interception: the IP copy of the target’s traffic still contains every DNS packet, but with DoH and DoT those packets are encrypted, so the LEA loses the domain names it used to read from them. Encrypted DNS does not affect retained data: data retention rules, where they apply, cover subscriber and IP-assignment records. They do not cover DNS queries or browsing history, which in Germany are expressly excluded from data retention (\u00a7 176(5) TKG).<\/p>\n\n\n\n

L\u2019impatto \u00e8 pi\u00f9 grave quando il destinatario utilizza un resolver DoH di terze parti \u2014 come quelli gestiti da Cloudflare, Google o altri provider \u2014 anzich\u00e9 l\u2019infrastruttura DNS dell\u2019operatore stesso. In questo caso, le query DNS vengono risolte interamente al di fuori della rete dell\u2019operatore, che non ha alcun accesso alle stesse. Se il destinatario utilizza il resolver DNS proprio dell\u2019operatore con DoT o DoH, l\u2019operatore mantiene l\u2019accesso ai dati delle query a livello di resolver, ma non nei punti intermedi della rete.<\/p>\n\n\n\n

Strategie di mitigazione per gli operatori<\/h2>\n\n\n\n

Operators cannot prevent the adoption of encrypted DNS, but they can implement strategies to mitigate its impact on lawful interception. The first strategy is to operate their own DoH and DoT resolvers and to encourage their subscribers to use these resolvers, for example by advertising them through DDR (RFC 9462) or DNR (RFC 9463) so that devices upgrade to the operator’s encrypted resolver automatically. If the operator runs the encrypted resolver, an interception point at the resolver can still see a target’s queries in plaintext once a valid order is in force. This is not a reason to log all subscribers’ DNS: keeping such data needs its own legal basis. This approach preserves DNS visibility for lawful interception while still providing subscribers with the privacy benefits of encrypted DNS against third-party observation.<\/p>\n\n\n\n

The second strategy involves using alternative data sources to reconstruct the information that DNS queries previously provided. Server Name Indication (SNI) in TLS handshakes provides the domain name of the server that the client is connecting to, and this information has traditionally been transmitted in plaintext. However, Encrypted Client Hello (ECH, RFC 9849, published 2026, the successor to ESNI) now encrypts the SNI as well, wherever browser and server support it, further reducing visibility. IP address analysis can also provide some information about which services a target is accessing, but the widespread use of content delivery networks (CDNs) and shared hosting means that IP-to-domain mapping is often ambiguous.<\/p>\n\n\n\n

The third strategy is to implement interception at the application layer or at the device level, rather than relying solely on network-level data. This approach is beyond the scope of traditional telecommunications interception, but some jurisdictions already permit device-level interception under strict conditions (in Germany, ‘Quellen-TK\u00dc’ under \u00a7 100a StPO), as a response to the increasing encryption of network traffic. For operators, this is not a practical solution, but it is part of the broader context in which encrypted DNS should be understood.<\/p>\n\n\n\n

A fourth strategy involves regulatory and policy engagement. Outside the EU, some governments block third-party resolvers or encrypted handshakes. In the EU, net-neutrality rules (Regulation (EU) 2015\/2120) make such blocking by operators difficult without a specific legal basis. These approaches are controversial and raise questions about network neutrality, user freedom, and technical feasibility.<\/p>\n\n\n\n

La tendenza generale verso una maggiore crittografia<\/h2>\n\n\n\n

Il DNS crittografato fa parte di una tendenza pi\u00f9 ampia verso la crittografia di tutto il traffico di rete, guidata da preoccupazioni relative alla privacy, dalle migliori pratiche di sicurezza e dalle configurazioni predefinite delle principali piattaforme software. TLS 1.3, ECH, QUIC e altre tecnologie stanno progressivamente crittografando una parte sempre maggiore dei metadati e dei contenuti su cui si \u00e8 tradizionalmente basata l\u2019intercettazione a livello di rete. Ogni passo in questa direzione riduce la visibilit\u00e0 a disposizione degli operatori e, per estensione, quella delle attivit\u00e0 di intercettazione legittime.<\/p>\n\n\n\n

Gli operatori devono rendersi conto che la visibilit\u00e0 a livello di rete di cui hanno goduto in passato sta diminuendo e continuer\u00e0 a diminuire. La risposta a questa tendenza non pu\u00f2 essere puramente tecnica: richiede il coinvolgimento delle autorit\u00e0 di regolamentazione, degli organismi di normazione e delle forze dell'ordine per sviluppare nuovi approcci all'intercettazione legale che tengano conto delle realt\u00e0 di un ambiente di rete fortemente crittografato.<\/p>\n\n\n\n

At the same time, operators must continue to deliver whatever interception data they are technically capable of providing. The encryption of DNS does not eliminate the operator’s legal obligation to intercept; it changes the scope of what can be intercepted. Operators must remove encryption they apply in the network or whose keys they help generate or exchange (in Germany \u00a7 8(3) TK\u00dcV). Third-party DoH or DoT traffic is handed over as captured. Operators must be transparent with law enforcement about these limitations and must ensure that their LI systems are updated to handle the reduced visibility gracefully \u2014 delivering the complete copy of the target\u2019s traffic, encrypted DNS included, without filtering it.<\/p>\n\n\n\n

Implicazioni in materia di conformit\u00e0 e rendicontazione<\/h2>\n\n\n\n

Encrypted DNS does not reduce what an operator has to deliver: the complete copy of the target\u2019s traffic, including the encrypted DNS packets, still meets the obligation. What changes is what law enforcement can read from it, and operators should explain this when agencies ask why domain names are missing.<\/p>\n\n\n\n

Le autorit\u00e0 di regolamentazione di alcune giurisdizioni potrebbero dover aggiornare i propri requisiti tecnici e le proprie aspettative per tenere conto della realt\u00e0 del DNS crittografato. Gli operatori possono svolgere un ruolo costruttivo in questo processo, fornendo competenze tecniche e approfondimenti pratici per orientare lo sviluppo della normativa. L\u2019esito peggiore per tutte le parti sarebbe l\u2019aspettativa normativa che gli operatori forniscano dati ai quali non sono tecnicamente in grado di accedere \u2014 una situazione che crea un rischio di non conformit\u00e0 senza apportare alcun valore alle indagini.<\/p>\n\n\n\n

Conclusione<\/h2>\n\n\n\n

Encrypted DNS represents a significant shift in the balance between privacy and surveillance capability in telecommunications networks. DoH and DoT protect user privacy by preventing the observation of DNS queries by network intermediaries, but they also reduce the visibility available to lawful interception systems. Operators can help by offering their own encrypted DNS resolvers, leveraging alternative data sources, engaging with regulators on evolving requirements, and ensuring that their LI systems accurately reflect the data that is actually available. The trend toward comprehensive network encryption is irreversible, and operators that adapt proactively will be better positioned to maintain compliance and to provide meaningful support to law enforcement within the constraints of the evolving technical landscape.<\/p>\n\n\n

Il dibattito sul DNS crittografato mette inoltre in luce la tensione tra i diritti alla privacy dei singoli e le legittime esigenze delle forze dell\u2019ordine. Trovare il giusto equilibrio richiede la collaborazione tra esperti di tecnologia, responsabili politici, societ\u00e0 civile e forze dell\u2019ordine. Gli operatori si trovano al crocevia di questi interessi e hanno la responsabilit\u00e0 unica di garantire che le capacit\u00e0 tecniche, gli obblighi legali e le misure di tutela della privacy siano allineati. Partecipando attivamente allo sviluppo di standard, alle consultazioni normative e ai forum di settore, gli operatori possono contribuire a definire soluzioni che rispettino la privacy, preservando al contempo la capacit\u00e0 delle societ\u00e0 democratiche di condurre attivit\u00e0 di sorveglianza legittime nel rispetto dello Stato di diritto.<\/p>\n\n\n\n

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