Given domain "x.com", and the edge server named "edge.x.com" what would be the proper DN entries for external users? I tried the usual _sip, but they are not being picked up. The log shows me access attempts to connect to sip.x.com, but that is not coming "from anywhere" (no setting, no name).
Anyone can help?
The DNS requirements for Lync are listed at http://technet.microsoft.com/en-us/library/gg398758.aspx.
For your example you'd have the following in your external DNS:
_sip._tls.x.com SRV 0 0 443 sip.x.com (SRV record for automatic client logon)
_sipfederationtls._tcp.x.com SRV 0 0 5061 sip.x.com (federation SRV record)
sip.x.com A (SIP Access Public IP)
web.x.com A (Web Components Public IP)
av.x.com A (AV Public IP)
Also, be aware of the certificate requirements on your AP's external edge for federation. The public FQDN by which your AP is known must be present in either the SN or SAN of the certificate, along with any other FQDNs if you are hosting multiple domains. The prefixes shown in Jachin's response are recommended; e.g. for domain "x.com", it is best to name your AP "sip.x.com".
