Foreman allows underscores in hostnames
If I enter a hostname with an underscore in it while creating a new host,
eg "ore1-func_2", then foreman won't complain although the smart-proxy won't be able to update the dns record.
#4 Updated by Ewoud Kohl van Wijngaarden almost 9 years ago
Since those host names are not allowed by the DNS RFC, it should be discouraged. (In practice it may or may not work since most software does accept it.) From http://domainkeys.sourceforge.net/underscore.html: Host names are not allowed to have underscores in them. In DNS, host names are the name fields of A or MX records or the data fields of the SOA and NS records. Thus, there are many DNS entries that are not hostnames.