Make sure you can use their SMTP servers for outgoing email. Many hosting and domain name registration providers will not let you use their SMTP servers for sending emails. They assume you can send email via your internet server provider’s SMTP servers. However, a great many ISPs and broadband providers will only let you use their SMTP servers on their branded email accounts (i.e. [email protected]). This means that if you use your own email address (i.e. [email protected]), you won’t be able to send email via their SMTP servers. There are workarounds but you shouldn’t have to go to the trouble.
When looking up a bare name in DNS, the network stack will add the search domains to it to form fully qualified domain names, and look up those as well. For example, if the domain search list contains "wikipedia.org", typing "en" in the browser will direct the user to "en.wikipedia.org". Some ISPs add their own search domains via DHCP settings, similar to how they add DNS servers and other networking information; if this is undesired, the user can change this setting to ".local".