8. Security Considerations

This section preserves the RFC text for Unreachable Prefix Announcement (UPA), including IS-IS and OSPF signaling, U-Flag and UP-Flag semantics, propagation rules, IANA assignments, and security considerations.

8.  Security Considerations

   The use of UPAs introduces the possibility that an attacker could
   inject a false, but apparently valid, UPA.  However, the risk of this
   occurring is no greater than the risk today of an attacker injecting
   any other type of false advertisement.

   The risks can be reduced by the use of existing security extensions
   as described in:

   *  [RFC5304], [RFC5310], and [RFC7794] for IS-IS.

   *  [RFC2328], [RFC7474], and [RFC7684] for OSPFv2.

   *  [RFC5340], [RFC4552], and [RFC8362] for OSPFv3.