iana: Remove hardcoded multicast prefixes #8456
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Remove multicast IP prefixes (RFCs 3171 & 4291) from the hardcoded list of reserved addresses in the iana package. These prefixes are not listed in IANA's Special-Purpose Address Registries or otherwise forbidden by the Baseline Requirements, so hardcoding them in Boulder probably isn't appropriate. Instead, operators can configure them in `AdminBlockedPrefixes` to prevent their use as identifiers, and use their resolvers' configuration (e.g. Unbound's `private-address` and `do-not-query-address` directives) to exclude them from DNS query results. Part of #8237
aarongable
approved these changes
Oct 27, 2025
Contributor
aarongable
left a comment
aarongable
left a comment
There was a problem hiding this comment.
LGTM, but given that this requires a config change to retain the same functionality, please indicate in the PR description which internal ticket documents that change and whether it has been completed yet.
aarongable
requested review from
a team and
jsha
and removed request for
a team
beautifulentropy
approved these changes
Oct 31, 2025
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Remove multicast IP prefixes (RFCs 3171 & 4291) from the hardcoded list of reserved addresses in the
ianapackage.These prefixes are not listed in IANA's Special-Purpose Address Registries or otherwise forbidden by the Baseline Requirements, so hardcoding them in Boulder probably isn't appropriate.
Instead, operators can configure them in
AdminBlockedPrefixesto prevent their use as identifiers. For Let's Encrypt, this has been done in IN-11854. They can also use their resolvers' configuration (e.g. Unbound'sprivate-addressanddo-not-query-addressdirectives) to exclude them from DNS query results. For Let's Encrypt, this has been done for a long time (since before the current config's first blame).Part of #8237