Which DNS SRV (Service Location) records should I create for a domain


This article describes which SRV records should be created for a domain. These SRV records allow clients to automatically detect which host and port should be used for relevant domain services.


SRV records (known as Service Location Records) are used by clients to automatically configure the host and port for messaging services when an account is created. These records are created within the advertised DNS zone for a domain.

Whilst Microsoft clients typically use an autodiscovery service to detect mail client settings, many clients (particularly iOS/OSX and mobile clients) will use DNS to locate a user's messaging service settings.


The following table lists typical SRV records that should be created for a domain to improve the experience when user's create e-mail accounts:

SRV Record Description
_caldav CalDAV Calendaring Support
_caldavs CalDAV Calendaring Support over SSL
_carddav CardDAV Address Book Support
_carddavs CardDAV Address Book Support over SSL
_imap IMAP Mail Access Support
_imaps IMAP Mail Access Support over SSL
_pop3 POP3 Mail Access Support
_pop3s POP3 Mail Access Support over SSL
_submission SMTP Client Mail Transfer Support
_autodiscover Specifies the server and port responsible for providing autodiscovery for mail services (via MailEnable's Autodiscovery Service)


These DNS records typically appear within a domains DNS Zone as: [SRV]._tcp.example.com.

The process for configuring these records depends on which vendor is providing DNS for the domain. It can only be done by a person who has administrative access to the DNS service responsible for the domain.

As an example, to create a DNS SRV record for IMAP using Microsoft's DNS, you should do the following:

  1. On the DNS server, click Start, click Control Panel, click Administrative Tools, and then click DNS.
  2. In the console tree for your domain, expand Forward Lookup Zones, and then right-click the domain in which you wish to create an SRV record.
  3. Click Other New Records.
  4. In Select a resource record type, click Service Location (SRV), and then click Create Record.
  5. Click Service, and then type _imap.
  6. Click Protocol, and then type _tcp.
  7. Click Port Number, and then type 143.
  8. Click Host offering this service, and then type the FQDN of the host providing IMAP connectivity. eg: mail.example.com
  9. Click OK.
  10. Click Done.



RFC-6186: https://tools.ietf.org/html/rfc6186

Android Autodiscovery: Article ME020622

Outlook Autodiscovery: Article ME020620

Outlook Connector: Article ME020637

Class:HOWTO: Product Instructions
Revised:Wednesday, February 14, 2018