Users occasionally cannot connect

[Lakusfs]

Greetings,

If this question has been asked before, I apologize and please redirect me to the appropriate thread. PLEASE do not answer with "READ THE FAQ", I have already done so, and I cannot find an acceptable answer there or in any of the forums.

I have TS version 2.0.20.1 running on a Windows 2003 server as a service using srvany. I run my server on an alternate port, 9958, and I have the correct port mapping set up through my D-Link router to allow internet traffic to my server's static private IP address. I use a no-ip.com stub to add DDNS to my dynamic ISP-provided external IP address. My TS server requires a password, but not individual registered accounts.

90% of my users connect fine, all the time, no problems.

A few of my users, however, get the "cannot connect to server, check to see if the server is running" message about 90% of the time they try to connect to it. Every once in a while, though, these users can connect.

Previous troubleshooting:
I have made sure it was not a data entry error on the users' part by having them add a server entry into their local address list, and using only that entry to connect.
I have tried running the TS server on my end on different ports and the standard port.
I have tried disabling the password requirement on the TS server
I have tried having the users connect by IP instead of the DNS name.
I have had the users disable all firewalling or routing on their end temporarily.

All the possibilities we have tried so far have not produced any repeatable change in their ability to connect. It has been theorized that if one of these users is the first to connect to the TS server, then that helps their chances of successfully connecting, but to my knowledge that has not been shown to be repeatable yet.

The behavior I have observed from my users' efforts seems to me very much like what I would expect of a port range issue, like TS uses the defined port as a trigger port and then uses a subsequent connection on another dynamic port in an upper range. To test this theory, I used my router's DMZ feature to temporarily place the server above the firewall, but this also had no observable change in my failing clients' ability to connect consistently.

I would greatly appreciate assistance from someone with sufficient technical background with the TS server to offer some suggestions for further troubleshooting techniques, possible changes to the server, tweaks to the client, additional information I could collect, etc.

[Bastian]

Could you please attach some logs of the server and / or connecting clients? This might help finding the problem.

[guldi]

Have the users getting a "no reply" tested the TS debug mode as recommended in the TS FAQ (see timeout section) ?

[Lakusfs]

I will skip my incredibly caustic responses to "have you read the FAQ..."

Here is a debug log from one of my clients that occasionally cannot connect to my server, taken at a period when he was experiencing the error. Please let me know if you are able to determine anything from this information.

FYI, I left this setup data out of my original post. I am behind a D-Link DI-614 router with all the appropriate ports forwarded. This may have relevance because of a new post in the forums with a user that is having similar issues to mine.