On 10/22/19 10:11 PM, Grant Taylor via NANOG wrote:
The explicit nature of RFC 6598 is on purpose so that there is no chance that it will conflict with RFC 1918. This is important because it means that RFC 6598 can /safely/ be used for Carrier Grade NAT by ISPs without any fear of conflicting with any potential RFC 1918 IP space that clients may be using.
RFC 6598 ∉ RFC 1918 and RFC 1918 ∉ RFC 6598 RFC 6598 and RFC 1918 are mutually exclusive of each other.
Yes, you can run RFC 6598 in your home network. But you have nobody to complain to if (when) your ISP starts using RFC 6598 Shared Address Space to support Carrier Grade NAT and you end up with an IP conflict.
Aside from that caveat, sure, use RFC 6598.
So, to the reason for the comment request, you are telling me not to blackhole 100.64/10 in the edge router downstream from an ISP as a general rule, and to accept source addresses from this netblock. Do I understand you correctly? FWIW, I think I've received this recommendation before. The current version of my NetworkManager dispatcher-d-bcp38.sh script has the creation of the blackhole route already disabled; i.e., the netblock is not quarantined.