On Tue, May 14, 2024 at 1:24 PM, Tom Beecher <beecher@beecher.cc> wrote:
That means that some IP addresses in the block 192.0.0.0/24 may be
routable.
It feels like people are talking past each other when they are saying "routable" — these are fairly clearly not routable on the Global Internet, but addresses like 192.0.0.10/32 (the TURN anycast address) look like they are intended to be routed within a network: "IP anycast can also be used for TURN service discovery. A packet sent to an anycast address is delivered to the "topologically nearest" network interface with the anycast address." but this is clearly not **supposed** to leak: "In a network without any TURN server that is aware of the TURN anycast address, outgoing TURN requests could leak out onto the external Internet, possibly revealing information. Using an IANA-assigned well-known TURN anycast address enables border gateways to block such outgoing packets. In the default-free zone, routers should be configured to drop such packets." W
So, I would not make this a bogon.
This ignores note 2 on the IANA definitions page, next to 192.0.0.0/24 :
[2]
Not useable unless by virtue of a more specific reservation.
Which then lists the more specific reservations, of which SOME are forwardable , and some are not.
The categorization as 'bogon' or not would really be determined by individual operator use cases, and where/how such a bogon filter is applied.
On Tue, May 14, 2024 at 12:23 PM Jakob Heitz (jheitz) via NANOG <nanog@ nanog.org> wrote:
RFC 5736 was obsoleted by RFC 6890.
It says in part:
2.2.1. Information Requirements
The IPv4 and IPv6 Special-Purpose Address Registries maintain the
following information regarding each entry:
…
o Forwardable - A boolean value indicating whether a router may
forward an IP datagram whose destination address is drawn from the
allocated special-purpose address block between external
interfaces.
…
That means that some IP addresses in the block 192.0.0.0/24 may be routable.
So, I would not make this a bogon.
A better way to filter IP routes is by policy, for example based upon
IRR and RPKI records.
Kind Regards,
Jakob
---------- Original message ----------
Date: Tue, 14 May 2024 12:00:15 +0200 (CEST) From: borg@uu3.net
[10] 192.0.0.0/24 reserved for IANA IPv4 Special Purpose Address Registry [RFC5736]. Complete registration details for 192.0.0.0/24 are found in [IANA registry iana-ipv4-special-registry].
Was RFC5736 obsoleted? I think not, so I would treat it as bogon.
Its a nice tiny subnet for special purposes. I personaly use it as my Internal VM Net on my desktop for example.
---------- Original message ----------
From: John Kristoff <jtk@dataplane.org> To: NANOG <nanog@nanog.org> Subject: On consistency and 192.0.0.0/24 Date: Mon, 13 May 2024 16:18:47 -0500
As one to never let a good academic question go unasked... what is it about 192.0.0.0/24 that is or isn't a bogon. This doesn't seem so straightforward an answer to me, at least in theory. Although in practice it may already be decided whether one likes the answer or not.
192.0.0.0/24 was originally assigned to IANA for "protocol assignments" in IETF RFC 5736, and later added to the list of reserved / special use addresses in IETF RFC 6890 (aka BCP 153). There is a corresponding IPv6 block (2001::/23), but it has a significantly different history.
Team Cymru's bogon list includes the v4 prefix. NLNOG's bogon filtering guide does not. When I asked Job about NLNOG's position he said:
"I was unsure what this prefix??s future plans would be and erred on the side of caution and didn??t include this prefix in the NLNOG bogon list recommendations."
The /24 as specified is not for "global" use, but some of the more specific assignments are or can be. See: <https://www.iana.org/assignments/iana-ipv4-special-registry/ iana-ipv4-special-registry.xhtml>.
From my cursory examination I can't find cases where the v4 prefix or more specifics have been publicly announced to any significant degree. This however is not the case for the IPv6 prefix (e.g., the AS112 project, Teredo).
Maybe you'd say the /24 should be filtered, but not the more specifics that are deemed available for global use. That might be reasonable, except many reasonable people will filter small prefixes.
IANA's language may have put any "do not filter" camp in a relatively weak position:
"Address prefixes listed in the Special-Purpose Address Registry are not guaranteed routability in any particular local or global context."
I can't remember hearing anyone complaining about bogon-related reachability problems with the aggregate IANA prefixes generally. Is there a strong case to make that ops should not bogon filter any addresses in these prefixes? At least with IPv4? What about for IPv6?
John