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edns0

Since: Version 2025.03.19-1d3f1f67

The functionality described in this section requires version 2025.03.19-1d3f1f67 of KumoMTA, or a more recent version.

Boolean. Enables EDNS0, which permits larger UDP responses (typically up to the negotiated EDNS payload size rather than the legacy 512 byte limit). Required in practice for DNSSEC and for DKIM/MTA-STS/DMARC TXT lookups that may be larger than 512 bytes. Defaults to true.