What is '_autodiscover._tcp' in DNS settings?

45,776

Solution 1

SRV DNS records allow the use of DNS for publishing services and service discovery. Their main use is to allow services to run easily on non-standard ports and to reduce the configuration burden when setting up clients.

A SRV record has the following form:

_Service._Protocol.Name. TTL Class SRV Priority Weight Port Target

Service: the symbolic name of the service.
Protocol: the transport protocol of the service; this is usually either TCP or UDP.
Name: the domain name terminated with a . for which this record is valid - often omitted in DNS shorthand which then defaults to the zone name.
TTL: standard DNS time to live field.
Class: standard DNS class field (this is always IN for Internet).
Priority: the priority of the target host, lower value means more preferred.
Weight: A relative weight for records with the same priority.
Port: the TCP or UDP port on which the service is to be found.
Target: the canonical hostname of the machine providing the service.

Yours appears an example of an autodiscovery service :) pointing to TCP port 443 on the aptly named host autodiscover.*hostname*.net.

One such autodiscovery service seems to be used in automatically configuring MS Outlook but that may not be the only use-case.

Solution 2

It is likely related to your Exchange server.

Autodiscover for Exchange.

45,776

christoflee

I am a Junior Web Developer at a design agency. Originally I built websites using the CMS Modx, but have now moved into Wordpress.

Updated on September 18, 2022

Comments

christoflee almost 2 years
On a domain, in the DNS settings is an SRV record named:
```
_autodiscover._tcp
```
and value is:
```
0 10 443 autodiscover.*hostname*.net.
```
What is it and what does it do?

I am migrating websites to a new server and I need to know how this will work with the new server on a different host.
David Tonhofer about 9 years

Absolutely, and it allows Outlook to "discover the Exchange autodiscover service", whatever that means. See also: A new feature is available that enables Outlook 2007 to use DNS Service Location (SRV) records to locate the Exchange Autodiscover service. Not all domains may have it, so I suppose this is used to override a default that Outlook tries. Looks like there is an IIS server at the endpoint indicated.