Check out these advanced records definitions and examples.
TXT Records: Text records are used to describe a host or a DNS entry. You can enter anything you want as long as it is 255 characters or less. This feature is only available on Enhanced and Plus DNS. An example of this can be found by using dig.
dig google.com TXT
That shows Googles SPF record, which is in a TXT record.
;; ANSWER SECTION:
google.com. 3600 IN TXT “v=spf1 include:_netblocks.google.com ip4:22.214.171.124/31 ip4:126.96.36.199/31 ~all”
The TXT record of google.com is this,”v=spf1 include:_netblocks.google.com ip4:188.8.131.52/31 ip4:184.108.40.206/31 ~all” which is actually their SPF record.
SPF Records (Sender Policy Framework): Are used to prevent email forgery and help identify spam. To create an SPF record on No-IP.com, just manage your TXT record and use the SPF wizard to create an entry. This feature is only available on Enhanced and Plus DNS.
DKIM records (Domain Key Records): Are used for email to verify the identity of the sending server to help cut down on spam. Want to add a DKIM record to your host? From the ‘Hosts/Redirects’ tab select the host you’d like to modify and then click on the ‘DKIM’ link within the Advanced Records section. This feature is only available on Enhanced and Plus DNS.
SRV records: An SRV record describes services offered by a host. It defines the location of a server (port number and hostname). They are commonly used in SIP (Session Initiation Protocol) and XMPP Extensible Messaging and Presence Protocol protocols. This feature is only available on Enhanced and Plus DNS.