RBLs are queried via DNS during mail acceptance. The IP is reversed and prepended to the RBL hostname; a returned A record means “listed.”
RBL
Realtime Blackhole List — a DNS-based list of IPs known for spam/abuse.
Realtime Blackhole List — a DNS-based list of IPs known for spam/abuse.
RBLs are queried via DNS during mail acceptance. The IP is reversed and prepended to the RBL hostname; a returned A record means “listed.”