Using SQL 2016 Enterprise Edition
The default instance will listen on 1433 and the DAC port will listen on TCP 1434. SQL Browser will listen on UDP 1434. Any subsequent named instances will get a dynamically allocated port from windows in the range 49152 to 65535 as will their DAC ports. Connection requests (including DAC) to those named instances will make a call to SQL Browser and told the port number.
You can use the SQL Server Configuration Tool to change the port for the named instance to a static port number, but there is no option to set the DAC port to a static port number.
When I suggested to the networks team that I'd like the entire port range opened up for remote DAC connectivity, they were less than enthusiastic.
Is there any way to set the DAC port to a known, static port number for named instances?