DNS - having MX record without hostname + CNAME creates invalid zone file
ISPConfig should warn of or disallow empty hostname. and/or ISPConfig should inform administrator of invalid BIND zone file.
Technical details: DNS records shown by our ISPConfig GUI are:
Type Name Data Priority TTL A mail 10.0.0.11 0 3600 A test2.org. 10.0.0.11 0 3600 A www 10.0.0.11 0 3600 CNAME cnm www 0 3600 MX mail.test2.org. 10 3600 NS test2.org. ns1.nic.org. 0 3600 NS test2.org. ns2.nic.org. 0 3600
MX record has empty hostname field due to historical reasons. After upgrade to ISPConfig 3.0.5.4p1 an invalid zone file is generated. Domain is silently excluded from the BIND configuration (/etc/bind/named.conf.local) The zone file is renamed using suffix .err: pri.test2.org.err
The cause of that is: the CNAME record in zone file directly followed by the MX record with empty hostname. This causes invalid zone file: ... mail 3600 A 10.0.0.11 test2.org. 3600 A 10.0.0.11 www 3600 A 10.0.0.11 cnm 3600 CNAME www 3600 MX 10 mail.test2.org. test2.org. 3600 NS ns1.nic.org. test2.org. 3600 NS ns2.nic.org.
All the domain is inoperative on all DNS servers:-(
We can't see any warning.
Of course, after filling MX's hostname, DNS works fine...
Please, is it a bug or a feature?
It may be a similar bug as #3074 (closed).
Thanks, Vaclav