Function is_disallowed_ip 

pub fn is_disallowed_ip(ip: IpAddr) -> bool

Strict SSRF guard: true if ip must never be the target of a fetch under the default (most restrictive) policy.

Equivalent to is_blocked_address(ip, false): the union of the always-blocked ranges and the private/internal ranges. Retained as the canonical predicate used where private addresses are never acceptable.