Today I spent a few frustrating hours trying to debug a problem when connecting to the Lookup port (for historic data) on a specific machine. For the benefit of others who may encounter a similar problem and search this forum, here's a breakdown of the problem, causes, analysis and solution:

TL/DR: When any other application on the computer uses one of IQFeed's ports, it cannot be used in IQFeed. Solution: either remove the other application, or change IQFeed's default port assignment to some unused port.

Symptoms:

• Historic data failed to download, displaying errors about invalid data arriving on the Lookup port.
• The IQConnect.txt file did not display any connection message to the Lookup port (only to other ports).
• The Diagnostic utility was unable to listen to the Lookup port in the <Port Tester> tab, displaying an error message that "The specified address is already in use."

Diagnosis:
Open DOS Command Window (run as administrator) and run the following command:

netstat -abon

This will display all the active ports and the processes that hold them. For example, in my particular case the relevant line was this:

[lghub_agent.exe]
 TCP    127.0.0.1:9100         0.0.0.0:0              LISTENING       2312

This tells us that the culprit is the lghub_agent.exe process (part of Logitec's G-Hub application), process ID=2312

Solutions:

• Uninstall or disable the problematic other application
• Configure the other application to use a different port (this is often not possible, but sometimes is)
• Modify IQFeed's default port to use a different port number that is unused. For example, in the case of the Lookup port, the port number is stored in the registry key

  \\HKEY_CURRENT_USER\Software\DTN\IQFeed\Startup\LookupPort

  which you can modify using the Windows builtin regedit utility.

I hope this helps someone...

---

Yair Altman
IQML - IQFeed-MATLAB connector
https://UndocumentedMatlab.com/IQML

I am not a DTN employee; my post reflects my personal opinion
Edited by altmany on Apr 10, 2019 at 05:12 PM