TXT (Text) RECORD INFORMATION
This type of record is largely, but not only, used to define the Sender Policy Framework (SPF) which is used to verify permitted email sources for a specified domain. It's also used for Domain Keys which are used for a similar purpose. These records are just basic text which is read when required.
TXT records are in the format of Host → Data. (See example below).
From the above example the host has been set to @. This is most common for an SPF which is what is shown above. The data entered are values for setting an SPF within the TXT record.
The above example shows the format for an SPF entry. This requires the text 'v=spf1'.
The following 'a' signifies the A records for the current domain, IP4 address are also listed.
A colon separates the description and the IP whilst a space separates the different entries.
A hostname can also be added within this section and is preceded by 'include:'.
The ~all means that anything that isn't listed in this record is 'soft failed'.
Host
Host can be an @ character (most common) or an alpha-numeric string with periods, hyphens and underscores. Doesn't have to be a Fully Qualified Domain Name (FQDN)
Data
Data contains alpha-numeric characters, hostnames and IP addresses.
Please note that there is a limit of 255 characters in between " " (quote marks) for data.