Example Juniper config

protocols {
    bgp {
        group RTBH {
            type external;
            description RTBH;
            import RTBH-IN;
            export DENY-ALL;
            peer-as 65501;
            local-as 65500;
            neighbor 192.168.2.66;
        }
    }
}
policy-options {
    policy-statement RTBH-IN {
        term RTBH-IN {
            from protocol bgp;
            then {
                community add DONT-ANNOUNCE;
                next-hop discard;
                accept;
            }
        }
        then reject;
    }
    policy-statement DENY-ALL {
        then reject;
    }
    community DONT-ANNOUNCE members 65500:666;
}