Port 1433 Blocked

Port 1433 Blocked
Image by Gerd Altmann from Pixabay

I am running a Windows Azure worker role which exposes a WCF service on port 1433, which is also defined to be an input TCP endpoint:

The same worker role also exposes another service on TCP port 443, defined similarly:

I see both endpoints in the Management Portal, I am able to connect to the TcpInterfaceEndpoint at port 443 correctly, but I am not able to connect to the other port at all (tried from two different computers which are both able to access SQL servers outside, i.e. the port is not blocked for outgoing connections). When I tried to connect locally on the Azure instance (via Remote Desktop connection), telnet connected OK. Attempt to connect from elsewhere ends with “Connection timed out”. Everything seems to suggest port 1433 is handled differently to port 443, and is blocked by a firewall somewhere. I have even tried to completely disable Windows Firewall on the Azure instance, but nothing changed.

It would seem Azure is not allowing endpoints on port 1433 (which is normally MS SQL Server, we use it currently because of firewall restrictions in the testing environment), but I was not able to find any information on such limits anywhere. So – is it the case, or am I doing some trivial error somewhere?

Added: I tried another test: I switched both ports in the config file, so that WCF now runs at 443 and TCP at 1433. And, as I expected – the WCF service is available, while the TCP interface stops working. I am now quite convinced 1433 is, indeed, blocked in some way. It would just be fine to see this information documented somewhere.

Source: stackoverflow.com