Hi, At my job, we're migrating an ERP System from a Linux server with Informix database to a Windows 2008 R2 server with SQL Server 2008 using a tool that treats the same programming code on both environments. On the older server, this system was called via Telnet, so we kept the same way on the new server (now using the TELNET command on windows prompt - we've changed the login.cmd file to call the ERP system and close the connection on the exit). It was working fine while there were about 20 users connected via TELNET. But now, as we have migrated more databases from that system (increasing the number of users), we often have the message "No more connections are allowed to telnet server. Please try again later.", or even the TELNET command doesn't get any response from the server. Looking at the Event Viewer, there's a TCPIP warning (Event ID 4227), as shown in http://technet.microsoft.com/en-us/library/dd408475(WS.10).aspx, which also recommends disabling the network interface enabling it again. But, doing so, all active user connections will be killed, even those that are really in use (we've noticed that there are "lost" connections there; the user closes the TELNET command - usually clicking on the close button of the Command Prompt -, however the server keep it alive). Although new connections can't be made, the connected ones work fine. As we can't detect these lost connections, we're restarting our server in order to make it available again. We also have checked the TLNTADMN command. The configuration is shown below: D:\pHoTon_ERP_aplicativos>tlntadmn config The following are the settings on localhost Alt Key Mapped to 'CTRL+A' : YES Idle session timeout : 1 hours Max connections : 2001 Telnet port : 23 Max failed login attempts : 3 End tasks on disconnect : YES Mode of Operation : Console Authentication Mechanism : NTLM, Password Default Domain : transamerica State : Running D:\pHoTon_ERP_aplicativos> We have about 80 concurrent users, what is far from the maximum connection allowed by the telnet server. Do you know how we could solve this issue without restarting the network interface? Or preventing system for leaving lost connections on the server? Thanks!

Hi, Thanks for the detailed clarification. Firstly, I’d like to confirm that the error message was showing up when there are multiple telnet sessions on the same telnet client. In addition, please note that the “no more connection” error is because the Telnet Server will not allow more than 4 client sessions connected in pre-login status. That is to say, if you open 4 telnet sessions to the server from same computer, and did not type username/password in each session. The fifth telnet session will get the error message. This is by design, and we cannot increase the limit of 4 connections. So please close any telnet sessions hang on the login status, to see if the issue still persists. If you have any update or concerns, please feel free to let us know. Best Regards, Aiden

Hi, Thanks for the detailed clarification. Firstly, I’d like to confirm that the error message was showing up when there are multiple telnet sessions on the same telnet client. In addition, please note that the “no more connection” error is because the Telnet Server will not allow more than 4 client sessions connected in pre-login status. That is to say, if you open 4 telnet sessions to the server from same computer, and did not type username/password in each session. The fifth telnet session will get the error message. This is by design, and we cannot increase the limit of 4 connections. So please close any telnet sessions hang on the login status, to see if the issue still persists. If you have any update or concerns, please feel free to let us know. Best Regards, Aiden

Hi, Thanks for the detailed clarification. Firstly, I’d like to confirm that the error message was showing up when there are multiple telnet sessions on the same telnet client. In addition, please note that the “no more connection” error is because the Telnet Server will not allow more than 4 client sessions connected in pre-login status. That is to say, if you open 4 telnet sessions to the server from same computer, and did not type username/password in each session. The fifth telnet session will get the error message. This is by design, and we cannot increase the limit of 4 connections. So please close any telnet sessions hang on the login status, to see if the issue still persists. If you have any update or concerns, please feel free to let us know. Best Regards, Aiden

Hi, Aiden. Thanks for your help. We got it. The only problem we're facing now is when the telnet server did not answer to new client requests; on the same situation mentioned before, we're trying to telnet to the server but only a blank screen is shown (looks like the client is trying to find the server, eternally). Using commands like ping, tracert, etc, the server answer normally. As I've mentioned before, although new telnet requests are denied, already connected users work fine. If one of them leaves the server and try to open a new connection, this one will get a blank screen (until the restart of the network interface or the server). Also, lots of process from disconnected users remains alive on the server, and we don't know if these process could make the server unavailable like this. Please let us know if we're doing something wrong or what we could do to solve this issue. Another detail: Our server is a Virtual Server, hosted on a Physical Server with the same configuration. Best Regards, Almir

Hi, Aiden. Thanks for your help. We got it. The only problem we're facing now is when the telnet server did not answer to new client requests; on the same situation mentioned before, we're trying to telnet to the server but only a blank screen is shown (looks like the client is trying to find the server, eternally). Using commands like ping, tracert, etc, the server answer normally. As I've mentioned before, although new telnet requests are denied, already connected users work fine. If one of them leaves the server and try to open a new connection, this one will get a blank screen (until the restart of the network interface or the server). Also, lots of process from disconnected users remains alive on the server, and we don't know if these process could make the server unavailable like this. Please let us know if we're doing something wrong or what we could do to solve this issue. Another detail: Our server is a Virtual Server, hosted on a Physical Server with the same configuration. Best Regards, Almir

Hi, Aiden. Thanks for your help. We got it. The only problem we're facing now is when the telnet server did not answer to new client requests; on the same situation mentioned before, we're trying to telnet to the server but only a blank screen is shown (looks like the client is trying to find the server, eternally). Using commands like ping, tracert, etc, the server answer normally. As I've mentioned before, although new telnet requests are denied, already connected users work fine. If one of them leaves the server and try to open a new connection, this one will get a blank screen (until the restart of the network interface or the server). Also, lots of process from disconnected users remains alive on the server, and we don't know if these process could make the server unavailable like this. Please let us know if we're doing something wrong or what we could do to solve this issue. Another detail: Our server is a Virtual Server, hosted on a Physical Server with the same configuration. Best Regards, Almir