Check for glue records when needed

[seanthegeek]

https://tools.ietf.org/html/rfc7489#section-7.1

i.e. for

$ dig +short _dmarc.nhn.no TXT
"v=DMARC1\; p=none\; rua=mailto:dmarc@nhn.no,mailto:dsm1h58m@ag.dmarcian.com\; ruf=mailto:dmarcfull@nhn.no"

ag.dmarcian.com is external to nhn.no, so it needs to specify that it will accept reports for nhn.no this way:

$ dig +short nhn.no._report._dmarc.ag.dmarcian.com TXT
"v=DMARC1"