Email authentication
MX 레코드 (MX record)
Definition
DNS record pointing to a domain's inbound mail servers; inline gateways change it.
For executives (CEO·CISO)
Adopting inline (gateway) security routes mail through that system, which then becomes a single point of failure. Commonly missed: verify availability (redundancy) and fail-open/queue behavior at contract/design time — if the security system stalls, company mail can stall.