The IPv6 email mirage: 55.2% of MX "support" it, but two companies carry the entire story

Short summary

A DNS scan of 50,000 domains shows 55.2% have IPv6-capable MX records, but Google (100%) and Microsoft (91.3%) account for nearly all of it. Remove them and adoption drops to 12.9%. Enterprise security gateways like Proofpoint, Mimecast, and Barracuda are effectively not on IPv6. Email senders should plan for an IPv4 world with two big IPv6 exceptions.

• •55.2% of domains have IPv6 MX but Google and Microsoft carry nearly all of it
• •Enterprise gateways (Proofpoint, Mimecast, Barracuda) have near-zero IPv6 support
• •Dual-stack sending is mandatory; IPv4 remains the backbone for reputation and blocklists

Generated with AI, which can make mistakes.