The FCC's new rule, as delineated in our Client Advisory of February 7, 2025, requiring all voice service providers ("VSPs") to block suspicious calls based on a reasonable do-not-originate ("DNO") list was recently published in the Federal Register. As stated therein, the rule will be effective as of December 15, 2025.
The new rule, 47 C.F.R. 64.1200(o) extends the existing rule requiring gateway and messaging providers to block calls that are likely to be illegal based on a "reasonable DNO" to all VSPs.
The FCC declined to define the scope of a reasonable DNO, stating only that such a list could include "only invalid, unallocated, and unused numbers, as well as numbers for which the subscriber has requested blocking." The Commission added the caveat that it may "deem unreasonable a list so limited in scope that it leaves out obvious numbers that could be included with little effort." Moreover, the FCC will require VSPs to "constantly update DNO lists, especially if they include unused numbers that could go into use at any time..." The Commission acknowledged that smaller VSPs may use a less extensive DNO list than larger carriers, especially in situations where other VSPs in the call chain must block suspicious calls.
In sum, the FCC wants each VSP to prepare its own "provider-selected" DNO, because it presumably knows its own network, and is thus "better positioned to determine what types of numbers should be prioritized." Importantly, the FCC refused to impose a safe harbor for VSPs blocking on a reasonable DNO list because it does not know what liability a VSP would face for blocking based on same.
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