Troubleshooting Error: 1753 ( There are no more endpoints available from the endpoint mapper )

You may get the Error: 1753 ( There are no more endpoints available from the endpoint mapper ) when communicating with a Windows server. This error may be reported when a DC is Replicating Active Directory with its partner DC or when 2 servers are replicating files using FRS or DFSR etc.

So what should you interpret from this error?

This error means that there may not be any available ports for communication, on the server.
Ports can be utilized by services on the server, which may use it for listening. Apart from this, when the server established a session with the DC or another server, it will use a dynamic source port for it. So when all the available ports on the server are in use and the server cannot allocate another ports for communication, it returns the following error.

How-to Troubleshoot:

Connect to the server and collect the ‘Netstat –ano > netstat.txt’ output. This output will give us the summary of the network sessions on the server as well as it would tell us the PID of the process that owns the session.

===================================================
Active Connections

Proto Local Address Foreign Address State PID (PID of the process owning the session)
TCP 0.0.0.0:80 0.0.0.0:0 LISTENING 4
TCP 0.0.0.0:135 0.0.0.0:0 LISTENING 924
TCP 0.0.0.0:445 0.0.0.0:0 LISTENING 4
TCP 0.0.0.0:623 0.0.0.0:0 LISTENING 2460
TCP 0.0.0.0:1311 0.0.0.0:0 LISTENING 2412
TCP 0.0.0.0:3389 0.0.0.0:0 LISTENING 1060
TCP 0.0.0.0:49155 0.0.0.0:0 LISTENING 328
TCP 0.0.0.0:49502 0.0.0.0:0 LISTENING 320
TCP 0.0.0.0:49510 0.0.0.0:0 LISTENING 656
TCP 10.100.0.35:139 0.0.0.0:0 LISTENING 4
TCP 10.100.0.35:139 10.100.0.1:1152 ESTABLISHED 4
TCP 10.100.0.35:445 10.100.0.49:63298 ESTABLISHED 4
TCP 10.100.0.35:445 10.101.0.60:4779 ESTABLISHED 4
TCP 10.100.0.35:445 10.101.0.162:4681 ESTABLISHED 4-> PID of the SYSTEM process
TCP 10.100.0.35:445 10.101.0.164:1467 ESTABLISHED 4
TCP 10.100.0.35:445 10.101.0.170:1193 ESTABLISHED 4
TCP 10.100.0.35:445 10.101.2.92:3153 ESTABLISHED 4
TCP 10.100.0.35:3389 10.101.8.12:2575 ESTABLISHED 1060
TCP 10.100.0.35:49493 10.100.0.113:1025 ESTABLISHED 3424
TCP 10.100.0.35:49497 10.100.0.112:389 ESTABLISHED 320
TCP 10.100.0.35:49499 10.100.0.112:1025 ESTABLISHED 320
TCP 10.100.0.35:49502 10.200.15.26:62352 ESTABLISHED 320
TCP 10.100.0.35:49502 172.27.2.136:55187 ESTABLISHED 320
TCP 10.100.0.35:50673 10.100.0.112:389 CLOSE_WAIT 4428
TCP 10.100.0.35:50902 10.100.0.112:389 CLOSE_WAIT 4428
TCP 10.100.0.35:50914 10.100.0.112:389 CLOSE_WAIT 4428
TCP 10.100.0.35:51498 10.100.0.112:389 CLOSE_WAIT 320
TCP 10.100.0.35:51762 10.100.0.112:1025 TIME_WAIT 0
TCP 10.100.0.35:51774 10.100.0.1:8014 ESTABLISHED 504
TCP 10.100.0.35:51775 10.100.0.111:1025 TIME_WAIT 0
TCP 10.100.0.35:51790 10.100.0.56:139 TIME_WAIT 0
TCP 10.100.0.35:51792 10.100.0.5:135 ESTABLISHED 924
TCP 10.100.0.35:51793 10.100.0.112:445 TIME_WAIT 0
TCP 10.100.0.35:51794 10.100.0.5:135 TIME_WAIT 0
TCP 10.100.0.35:51796 10.100.0.5:49153 TIME_WAIT 0 --> session is closed.
TCP 10.100.0.35:51797 10.100.0.5:49152 TIME_WAIT 0
==========================================================

From the Netstat output check how many active sessions are there on the server. If there are a lot of active ports on the server, check which process owns most of them.

If one process owns most of the ports, it may indicate a problem where the process may not be releasing ports, or there might be a lot of incoming and outgoing connections to that process.

--> Check if Killing/Ending the process resolves the above error temporarily.
--> If the port usage by this process is unusual, this need to be investigated further.

It may be that the port usage is normal as per the role of the server but the available ports on the server are less. By default, in Windows 2000/2003, ephemeral ports are allocated from port number 1024 through port number 5000, until the range is increased using the ‘MaxUserPort’ registry value. The ‘MaxUserPort’ value specifies the highest port number that TCP can assign when an application requests an available user port from the system. ‘MaxUserPort’ can take in value between 5000 and 65534.

The default dynamic port range for TCP/IP has changed in Windows Vista and in Windows Server 2008
http://support.microsoft.com/?id=929851

--> Try to increase the available port range using ‘MaxUserPort’ and Reboot the server.
HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Create a new REG_DWORD value ‘MaxUserPort’ with decimal value of 65534.

At times, you will see the above error even if all the ports from the available range are not exhausted. This is when you should check if the below configuration is in place.

HKEY_LOCAL_MACHINE\Software\Microsoft\Rpc\Internet –
Ports = Range port ports like 1024-1124

How to configure RPC dynamic port allocation to work with firewalls
http://support.microsoft.com/kb/154596

--> If the above registry value is set, then try to increase the range of the ports specified by another 100 ports and reboot to check if it helps.


Hope the above troubleshooting steps help :-)