The following are DNS records used by OS X Server services. Not all records are required for all services.
A (address)
An A record is required. It maps your server’s host name to its IP address. If you have an Internet router, your server has a unique, private IP address on your intranet, but on the Internet it uses the router’s public IP address.
PTR (pointer)
A PTR record is required. It maps your server’s IP address to its host name (reverse lookup). If you have an Internet router, your server has a unique, private IP address on your intranet, but on the Internet it uses the router’s public IP address.
MX (mail exchange)
If your server provides Mail service, the optional MX record specifies that your server is a mail server for your domain. An MX record lets users have an email address such as mchen@example.com. Without an MX record, email addresses must include your server’s full host name (for example, mchen@server.example.com).
CNAME (alias)
One or more optional CNAME records provide convenient access to services your server provides, such as mail.example.com and www.example.com.
SRV (service record) for Contacts service
If your server provides Contacts service, you can add an optional SRV record for Contacts service’s CardDAV protocol.
If you have an SSL certificate for Contacts service, add a record that maps _carddavs._tcp for port 8443 to your server’s host name. For example:
_carddavs._tcp 86400 IN SRV 0 1 8443 server.example.comIf you don’t have an SSL certificate for Contacts service, add a record that maps _carddav._tcp for port 8008 to your server’s host name. For example:
_carddav._tcp 86400 IN SRV 0 1 8008 server.example.comSRV for Calendar service
If your server provides Calendar service, you can add an optional SRV record for Calendar service’s CalDAV protocol.
If you have an SSL certificate for Calendar service, you can add an optional record that maps _caldavs._tcp for port 8443 to your server’s host name. For example:
_caldavs._tcp 86400 IN SRV 0 1 8443 server.example.comIf you don’t have an SSL certificate for Calendar service, add a record that maps _caldav._tcp for port 8008 to your server’s host name. For example:
_caldav._tcp 86400 IN SRV 0 1 8008 server.example.comSRV for Messages service
If your server provides Messages instant messaging service, you can add two optional SRV records for Messages server’s XMPP (Jabber) protocol.
One record controls connections between your server and other XMPP servers. It maps _xmpp-server._tcp for port 5269 to your server’s host name. For example:
_xmpp-server._tcp 86400 IN SRV 0 1 5269 server.example.comAnother record controls Messages and other XMPP client connections to your server. It maps _xmpp-client._tcp for port 5222 to your server’s host name. For example:
_xmpp-client._tcp 86400 IN SRV 0 1 5222 server.example.comThese SRV records let users have a Messages address such as mchen@example.com. Without these SRV records, Messages addresses must include your server’s full host name (for example, mchen@server.example.com).