Ssms cannot connect to a default instance of SQL Server without specifying a port number

Question

I have multiple instances of SQL Server 2005 in a box. From SSMS on my desktop, I can easily connect to this mailbox with instance names. After recent network configuration changes, when I want to connect to the default instance from SSMS on my desktop, I have to specify the port number. Before changing the network, I did not need to specify the default instance port number.

If I am removed from any other window (including the one in question), and use this SSSS to connect to this instance by default, success. From my desktop, and only from my desktop, I must specify the port number.

Is this the SQL Server configuration I missed? Is it possible something in my PC configuration is interfering? Where would I look, or what can I pass on to network users to help them solve this? Any help is appreciated.

Answer 1

Port 1434 is blocked somewhere along the line that is used to resolve the instance name to the port number.

If you specify a port number, the instance name is ignored ...

SQL Server Browser Service listens on port 1434

SQL Server UDP 1434. SQL , SQL Server , , . , SQL Server , SQL . SQL Server [sic] ipv6 ipv4.

SQL Server SQL , UDP 1434. SQL Server TCP/IP . , , .

, :

? , 1433, , .

" SQL Server".. " SQL".. " ".. tcp/ip, , .

Answer 2

Windows 2008/7/Vista, . , . , SSMS DTExec, . script, , , , SSMS DTExec.

rem SSMS
netsh advfirewall firewall add rule name=SQL-SSMS dir=in action=allow program="D:\Apps\Program Files (x86)\Microsoft SQL Server\100\Tools\Binn\VSShell\Common7\IDE\Ssms.exe" enable=yes profile=domain
netsh advfirewall firewall add rule name=SQL-SSMS dir=out action=allow program="D:\Apps\Program Files (x86)\Microsoft SQL Server\100\Tools\Binn\VSShell\Common7\IDE\Ssms.exe" enable=yes profile=domain

rem DTExec
netsh advfirewall firewall add rule name=SQL-DTExec dir=in action=allow program="D:\Apps\Program Files\Microsoft SQL Server\100\DTS\Binn\DTExec.exe" enable=yes profile=domain
netsh advfirewall firewall add rule name=SQL-DTExec dir=out action=allow program="D:\Apps\Program Files\Microsoft SQL Server\100\DTS\Binn\DTExec.exe" enable=yes profile=domain

rem DTExec32
netsh advfirewall firewall add rule name=SQL-DTExec32 dir=in action=allow program="D:\Apps\Program Files (x86)\Microsoft SQL Server\100\DTS\Binn\DTExec.exe" enable=yes profile=domain
netsh advfirewall firewall add rule name=SQL-DTExec32 dir=out action=allow program="D:\Apps\Program Files (x86)\Microsoft SQL Server\100\DTS\Binn\DTExec.exe" enable=yes profile=domain