When sending e-mails, it is very important to be identified as a trustworthy sender. In order to be recognised as an authentic sender (and so recognise your e-mails from those with a counterfeit sender), you can make use of the SPF (Sender Policy Framework) protocol, which allows users to verify whether a given e-mail actually comes from the declared source, by checking whether the IP address from which the message comes is among those authorised to send it.

SPF requires that we declare the list of servers authorised to send our mail (SMTP servers), by publishing on the DNS servers a particular record (SPF record) that contains the IP addresses of these sending servers. In this way, for example, if e-mails arrive with our sender, it will be easy for the recipient to check whether the sender is genuine by making a simple query to the SPF records.

Hosting Solutions allows SPF records to be created/edited from the control panel (in the area relating to the domain in question, select the Gestione DNS tab, Avanzate tab and insert the SPF record in the editor of the DNS area, saving the modification) and provides features to facilitate the inclusion of outgoing mail servers from your network in these records.

In particular, you can include all outgoing IP addresses available on the Hosting Solutions network by including one of the two SPF records created specifically by Hosting Solutions in your SPF record called _spfstrict and _spfpermissive, where:
- _spfstrict should be used if you only use Hosting Solutions servers to send your mail, or if you already use an SPF record with -all directive;
- _spfpermissive should be used if you also use Hosting Solutions servers to send your mail;

Below are the SPF records to be created/inserted:

• If you use only Hosting Solutions mail servers, create a record of this type:

  @ IN TXT "v=spf1 include:_spfstrict.interhost.it -all"

• if you already have an SPF record that contains the -all directive, then you will need to add to your record:
  

  include:_spfstrict.interhost.it

• if you already have an SPF record that contains the ~all directive, then you will need to add to your own record:
  

  include:_spfpermissive.interhost.it

For full information, these are the SPF records referred to in the directions above (WARNING: NOT to be inserted directly, but only via the include clause):

_spfstrict IN TXT "v=spf1 mx ip4:194.242.61.0/24 ip4:89.31.72.0/21 ip4:151.11.52.0/23
		 ip4:185.5.208.0/22 ip4:151.11.48.0/22 -all"

_spfpermissive IN TXT "v=spf1 mx ip4:194.242.61.0/24 ip4:89.31.72.0/21 ip4:151.11.52.0/23
		 ip4:185.5.208.0/22 ip4:151.11.48.0/22 ~all"