The DNS query is constructed by the client by taking _sipinternaltls._tcp and then adding whatever is to the right hand side of the symbol in the user sign in dialog box. This is important because this lets the client machine know whether it is logged in internally or externally. The first SRV record would be for internal client logins and the second one is for external (i.e. First, we see that the first two queries are for SRV (service locator) records. If we look at these DNS queries we notice a few things. I wanted to show how the Lync client automatically finds its servers for logon purposes.
Of course these failed as I have not done any of the DNS records for automatic client login support in my sandbox lab yet. So the client tried to query DNS for _sipinternaltls._tcp., _sip._tls., sipinternal., sip.
