Lync DNS Records

Internal

lyncdiscoverinternal.contoso.com  (A record for the Autodiscover service for internal connections directed to internal Web services)

_sipinternaltls._tcp.contoso.com (SRV record for internal TLS connections)

_sipinternal._tcp.contoso.com (SRV record for internal TCP connections)

sipinternal.contoso.com (A record for the Front End pool)

Extarnal

lyncdiscover.contoso.com (A record for the Autodiscover service for external Web services)

_sip._tls.contoso.com (SRV record for external TCP connections)

sip.contoso.com (A record for the Front End pool when the client is on the internal network; A record for the Access Edge Server when the client is external with no VPN access)

sipexternal.contoso.com (A record for the Access Edge Server when the client is external with no VPN access)