- contain only letters (a-z), numbers (0-9) and hyphens (-), or a combination of these

- start and end with an alphanumeric character, not a dash.

- do not contain a dash on the 3rd and 4th position (tagged domains).

- The name of the sub-domain must not refer to official aspects or topics of the country without due authorization.

- Sub-domain names that may be confused with some type of official and formal representation of the country will not be allowed.

- Unnecesary redundancy in the sub-domain names, such as the inclusion of the particles "sal", "es", "sv", as part of the name, must be avoided. The suffix ".sv", at the end of the complete name, is distinctive enough of the geographical nature of the name, and of its relationship to the name of the country El Salvador.

- It is recommended to use names that start with a letter and maintain a strong similarity with the name, abbrevaition or initials of the applying entity.

- Names considered offensive or against the principles of Internet will be subject to questioning and discussion with the applying enitity.

- The names that represent a concept within Internet and/or that may confuse or mislead users, such as "Internet", "InterNIC", "IANA", etc., will not be admitted.

- the domain name may not violate any trade mark.

In order to request the registration of a sub-domain name, the appropiate form must be completed, typed, in paper, and submitted, physically, to the Secretariat of the registry.

To transfer a domain name with the suffix ".sv" to another registrant, it's necessary that the current registrant mails a scanned copy of a signed letter (requesting the transfer) to Networking4all.