DoT (DNS over TLS)

Also known as: DNS-over-TLS

DNS over TLS (RFC 7858) encapsulates DNS queries inside a TLS 1.2+ session on TCP/853, providing confidentiality and integrity between resolver and client. In mobile networks DoT is relevant for UE-to-resolver privacy and for protecting inter-DNS traffic in the packet core, but also complicates lawful interception and DNS-based security controls.

Categories: Core NetworkSecurity ControlsProtocols and Standards

DoT in context

The mobile core is where subscriber sessions, mobility and policy live. In 4G it is the EPC (MME, HSS, S/PGW); in 5G it is the Service-Based Architecture with AMF, SMF, UPF, AUSF, UDM and the NRF. Core exposure is the difference between a single-subscriber leak and a fleet-wide breach.

Security controls in telecom span signaling firewalls (SS7/Diameter/GTP screening at the network edge), transport encryption (IPsec, TLS, PRINS), identity and access on OSS/BSS, and monitoring at both the packet and log level. Controls are audited against GSMA FS.11/FS.19/FS.20/FS.36 and, in Europe, NIS2 sectoral rules.

To place DoT in the wider telecom-security picture, review TNGF, AES, Core Network Security Assessment, HTTP, OpenSSL and MEC Security.

Related terms

Related topic hubs

  • SS7 Security SS7/MAP/CAP/SCCP attacks and defenses across 2G/3G interconnect.
  • SEPP Security N32-c/N32-f, PRINS, JWE and OAuth 2.0 at the 5G roaming edge.

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