This section contains a number of case studies that you may be able to use to resolve your own connectivity issues.

Note: IP addresses and machine names have been obfuscated into the 10.10.xxx.xxx, 172.[16-31].xxx.xxx, or 192.168.xxx.xxx range with generic names, such as SQLPROD01.CONTOSO.COM.
Note: Traces shown are parsed using NETMON 3.4.

In many cases, SQL Server is not listening on port 1433. Since there is no special code in TCP to indicate the sub-protocol type, the parser is hard-coded to interpret traffic on port 1433 as SQL Server traffic.

Change NETMON Parser Port for SQL Server

NTLM Connection Timeout due to Domain Controller

Network Device Interferes with Always-On Connections