DNS forwarder
A DNS forwarder is a nameserver that resolves queries by handing them to another nameserver instead of walking the authoritative chain itself, defined in RFC 8499's DNS terminology as sending a query with the RD (recursion desired) bit set rather than iterating through root, TLD and authoritative servers directly. Home routers and small-office DNS servers commonly run as forwarders, sitting between a device's stub resolver and an upstream recursive resolver -- often the ISP's, or a public one like 1.1.1.1 or 8.8.8.8 -- so the forwarder itself does little more than cache answers and pass queries on. Because a forwarder decides which upstream resolver every device on its network actually uses, a router quietly reconfigured to forward to an attacker-controlled resolver -- without ever changing any individual device's own DNS settings -- is a common, easy-to-miss form of DNS hijacking.
By AdminKit team, Netbase JSC · Updated