On Sat, May 05, 2012 at 09:00:00AM +0200, Thomas Faddegon wrote: > Hi PDNS community, > > I want implement empty CNAME records instead of empty A records in our DNS > environment. But when I implement the empty records my MX records won't > work anymore. > > Example: > > *nslookup > > set type=mx > > set debug > > online-engineers.nl > Server: 212.54.40.25 > Address: 212.54.40.25#53 > > ------------ > QUESTIONS: > online-engineers.nl, type = MX, class = IN > ANSWERS: > -> online-engineers.nl > mail exchanger = 20 mx2.global-e.nl. > ttl = 120 > -> online-engineers.nl > mail exchanger = 50 mx3.global-e.nl. > ttl = 120 > -> online-engineers.nl > mail exchanger = 20 mx1.global-e.nl. > ttl = 120 > AUTHORITY RECORDS: > ADDITIONAL RECORDS: > ------------ > Non-authoritative answer: > online-engineers.nl mail exchanger = 20 mx2.global-e.nl. > online-engineers.nl mail exchanger = 50 mx3.global-e.nl. > online-engineers.nl mail exchanger = 20 mx1.global-e.nl. > > Authoritative answers can be found from: > > * > > Then I add an empty CNAME: online-engineers.nl CNAME some.otherdomain.nl > > And I start a new nslookup: > * > > online-engineers.nl > Server: 212.54.40.25 > Address: 212.54.40.25#53 > > ------------ > QUESTIONS: > online-engineers.nl, type = MX, class = IN > ANSWERS: > -> online-engineers.nl > canonical name = some.otherdomain.nl. > ttl = 86400 > AUTHORITY RECORDS: > -> nl > origin = ns1.dns.nl > mail addr = hostmaster.domain-registry.nl > serial = 2012050309 > refresh = 7200 > retry = 900 > expire = 2419200 > minimum = 900 > ttl = 900 > ADDITIONAL RECORDS: > ------------ > ** server can't find online-engineers.nl: NXDOMAIN > Server: 212.54.40.25 > Address: 212.54.40.25#53 > > ------------ > QUESTIONS: > online-engineers.nl, type = MX, class = IN > ANSWERS: > -> online-engineers.nl > canonical name = some.otherdomain.nl. > ttl = 86400 > AUTHORITY RECORDS: > -> nl > origin = ns1.dns.nl > mail addr = hostmaster.domain-registry.nl > serial = 2012050309 > refresh = 7200 > retry = 900 > expire = 2419200 > minimum = 900 > ttl = 900 > ADDITIONAL RECORDS: > ------------ > ** server can't find online-engineers.nl: NXDOMAIN > > > > > > * > > And when I remove the empty CNAME everything works fine again: > * > > online-engineers.nl > Server: 212.54.40.25 > Address: 212.54.40.25#53 > > ------------ > QUESTIONS: > online-engineers.nl, type = MX, class = IN > ANSWERS: > -> online-engineers.nl > mail exchanger = 50 mx3.global-e.nl. > ttl = 120 > -> online-engineers.nl > mail exchanger = 20 mx1.global-e.nl. > ttl = 120 > -> online-engineers.nl > mail exchanger = 20 mx2.global-e.nl. > ttl = 120 > AUTHORITY RECORDS: > ADDITIONAL RECORDS: > ------------ > Non-authoritative answer: > online-engineers.nl mail exchanger = 50 mx3.global-e.nl. > online-engineers.nl mail exchanger = 20 mx1.global-e.nl. > online-engineers.nl mail exchanger = 20 mx2.global-e.nl. > > Authoritative answers can be found from: > * > > Is there a way to fix this? In the past I found an article (RFC, sorry I > can't find the source anymore) that officially empty CNAME's isn't allowed > in DNS. But many companies works with empty CNAME's , even google and > amazon. > > So I think there must be a way - or workaround - to fix this. > > I hope someone can give me a solution. > > Regards, > Thomas
Hi Thomas, Based on the RFC, if you have a CNAME record, you cannot have ANY other record with that name. That is just the way it works. Ken _______________________________________________ Pdns-users mailing list Pdns-users@mailman.powerdns.com http://mailman.powerdns.com/mailman/listinfo/pdns-users
