Question and response
Question
dig sf._domainkey.ubermetrics.com. NS
Answer
sf._domainkey.ubermetrics.com. 5 CNAME sf.f5o721.custdkim.salesforce.com.
Authority
custdkim.salesforce.com. 30 SOA mastername.salesforce.com. hostmaster.salesforce.com. 2041181975 1800 900 2592000 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0