网络工程 - 当 BGP 下一跳被覆盖到静态路由时，瞻博网络将接收到的 BGP 前缀保持在隐藏状态 - 吾爱随笔录

我有一个名为rtbh配置为 BGP 对等方的入口策略的路由策略：

root@PE3> show configuration policy-options policy-statement rtbh term ipv4 | display inheritance no-comments
from {
    family inet;
    community BLACKHOLE;
    route-filter 0.0.0.0/0 prefix-length-range /32-/32;
}
then {
    local-preference 170;
    origin igp;
    next-hop 192.0.2.1;
    accept;
}

root@PE3>

如上所示，如果它具有附加的特定 BGP 社区，则匹配 /32 前缀，然后将下一跳重写为192.0.2.1并接受该前缀。192.0.2.1存在的路径：

root@PE3> show route 192.0.2.1 detail

inet.0: 17 destinations, 18 routes (16 active, 0 holddown, 1 hidden)
192.0.2.1/32 (1 entry, 1 announced)
        *Static Preference: 5
                Next hop type: Discard, Next hop index: 0
                Address: 0xa1de64c
                Next-hop reference count: 2
                State: <Active NoReadvrt Int Ext>
                Local AS: 65005
                Age: 1
                Validation State: unverified
                Task: RT
                Announcement bits (2): 0-KRT 4-Resolve tree 1
                AS path: I

root@PE3>

root@PE3> ...configuration routing-options rib inet.0 | display inheritance no-comments
static {
    route 192.0.2.1/32 {
        discard;
        install;
        no-readvertise;
    }
}
martians {
    192.0.2.1/32 exact allow;
}

root@PE3>

但是，当我收到rtbh策略的匹配前缀时，它会保持隐藏状态：

root@PE3> show route receive-protocol bgp 10.94.0.1 extensive hidden

inet.0: 17 destinations, 18 routes (16 active, 0 holddown, 1 hidden)
  203.0.113.1/32 (1 entry, 0 announced)
     Accepted
     Nexthop: 10.94.0.1
     AS path: 65004 I
     Communities: 65005:666

inet6.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden)

root@PE3>

当我删除策略中的next-hop 192.0.2.1语句时，该语句rtbh将203.0.113.1/32变为活动状态。是什么导致了这种行为？