Lync Client 2013 Autodiscover

Auto-discover allow a Lync client to automatically locate the Lync Server based on the domain of your username. Auto-discover is something capital for your infrastructure that require a clean and comprehensive configuration of your DNS server. In oder to keep retro-compatibility Lync 2013 client will try the several method to reach your Lync server.

General usage

Lync client will try to contact the following server, if they are not available, it will try with the next one into the list:

Hard coded fqdn
# FQDN usage
1 lyncdiscoverinternal. A (host) record for the Autodiscover service on the internal Web services
2 lyncdiscover. A (host) record for the Autodiscover service on the external Web services
3 _sipinternaltls._tcp. SRV (service locator) record for internal TLS connections
4 _sipinternal._tcp. SRV (service locator) record for internal TCP connections (performed only if TCP is allowed)
5 _sip._tls. SRV (service locator) record for external TLS connections
6 sipinternal.<domain> A (host) record for the Front End pool or Director resolvable only on the internal network
7 sip.<domain> A (host) record for the Front End pool or Director on the internal network or the Access Edge service when the client is external
8 sipexternal. A (host) record for the Access Edge service when the client is external



When a user signs in to Lync for the first time, the user is prompted to save his or her password. If selected, this option allows the user’s client certificate to be stored in the personal certificate store and the user’s Windows credentials to be stored in the Credential Manager of the local computer.


Save Cert

Survivable Branch Appliance usage

  • SBA does not support lyncdiscoverinternal and lyncdiscover usage.
  • SBA must have the sip.domain as SAN of his certificate

Since the certificate authoriy is usually host into the Head Quarter, the computer session you are running must already contains the certificate for the user you plan to use if you want to authenticate during Wan outage.


Autodiscover cache

Lync 2013 caches the SIP address, user name, and password of every user who successfully signs in to Lync 2013 on a local computer. This allows the program to sign the previous user in to Lync again without requiring the user to enter their credentials. Lync 2013 stores credentials for multiple users. Individual users can select to make Lync 2013 clear the credential cache of their credentials by clicking the Delete my sign-in info link on the main Lync 2013 window before they sign in. Lync client store the autodiscover information into the registry:

  • Lync Client 2010: HKCU\Software\Microsoft\Communicator\Autodiscovery
  • Lync Client 2013: HKCU\Software\Microsoft\Office\15.0\Lync\\Autodiscovery

If you want to keep your certificate you can delete

  • HKCU\Software\Microsoft\Office\15.0\Lync\<YourUsername>\Autodiscovery
  • %localappdata%\Microsoft\Office\15.0\Lync\<YourUsername>

Clear DNS entries cache

It can be useful during test to clean the DNS cache to be sure your latest DNS change have been properly apply. On Windows type the following command in a prompt:
ipconfig /flushdns

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