Using DNS Wildcards, 10 November 2022

A “wildcard” is a DNS resource record whose owner’s name starts with an asterisk. It sounds like a very simple hack to save time when creating a lot of similar names, but there may be cases where a wildcard is not what you think it is. Test your knowledge with a tricky quiz about how various queries would be answered, given the zone contents (of course, with wildcard entries). Our presenter, Carsten Strotmann, will then explain: How are wildcard names expanded? Can wildcard domains have subdomains? How do wildcards work with DNSSEC? Can wildcard domains be empty non-terminal zones (ENTs)? What about wildcards and NSEC/NSEC3? In the end, you may be much more wary of using wildcards in your zone file. (The slides are available at https://www.isc.org/docs/2022-webinar...) You are welcome to post your questions about BIND 9 DNS on our helpful community mailing list at https://lists.isc.org/mailman/listinf.... The BIND Administrative Reference Manual is online at https://bind9.readthedocs.io/en/stable/. We also maintain a knowledgebase of handy technical articles at https://kb.isc.org. Internet Systems Consortium maintains and publishes the BIND 9 DNS software, under the open source MPL 2.0 license. ISC is a non-profit, operating to help support the Internet infrastructure and facilitate independent connection to and participation in the Internet. We support this work by offering users professional technical support contracts, including advance notification of security vulnerabilities before public disclosure. --- Learn more at https://www.isc.org.