What is the syntax of email address with a dot behind it? in DNS zone file, SOA rr

How i can use a email address with a dot in behind. For example at bellow, email address is [email protected], How to use [email protected] ?

example.com.    IN    SOA   ns.example.com. hostmaster.example.com. (...)

I can not use host.master.example.com. because email called [email protected]

Solution 1:

You can't (reliably). You can escape the dot (using a \) in the mailbox name, but this isn't always an option. Escaping the dot isn't officially standardized anywhere that I am aware of and although it is widely supported these days there isn't any guarantee that it will be properly parsed by any consumer of that information.

See the following resources:

http://www.zytrax.com/books/dns/ch8/soa.html email-addr

Email address of the person responsible for this zone and to which email may be sent to report errors or problems. In the jargon this is called the RNAME field which is why we called it email-addr. The email address of a suitable DNS admin but more commonly the technical contact for the domain. By convention (in RFC 2142) it is suggested that the reserved mailbox hostmaster be used for this purpose but any sensible and stable email address will work. NOTE: Format is mailbox-name.domain.com, for example, hostmaster.example.com (uses a dot not the more normal @ sign, since @ has other uses in the zone file) but mail is sent to [email protected]. Most commonly ending with a '.' (dot) but if the email address lies within this domain you can just use hostmaster (see also example below). when to use the dot.

https://www.ietf.org/rfc/rfc2142.txt

In DNS (see [RFC1033], [RFC1034] and [RFC1035]), the Start Of
Authority record (SOA RR) has a field for specifying the mailbox name of the zone's administrator.

This field must be a simple word without metacharacters (such as "%" or "!" or "::"), and a mail alias should be used on the relevant mail exchanger hosts to direct zone administration mail to the appropriate mailbox.

For simplicity and regularity, it is strongly recommended that the well known mailbox name HOSTMASTER always be used
.