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wiltomap
Asked: 2022-02-25 06:28:24 +0800 CST

MySQL connector/ODBC connection error following a DNS mismatch

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I have troubles configuring a new MySQL connection with ODBC Data Sources (64bits) utility on a Windows Server 2019. I'm using MySQL Workbench to define remote accesses as follow:

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The user is granted a SELECT only access:

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I have noticed that the server from which I need to initiate the connection (srv-bo) has a static IP address that had already been used in the past by another server (srv-mooc). The ancient remote server entry persisted in the domain controller DNS, so I deleted it. Since then, the ODBC Data Sources (64bits) utility keeps trying to connect with the ancient server's name (srv-mooc)... It seems that some connection informations are kept in memories somewhere but I can't figure it out.

So far, I have tried to flush the DNS cache on my Windows Server 2019 from which I initiate the connection. I have also tried to set up the connection from another user session and after server reboot. Issue is still there:

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Error message:

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The user credentials work fine from another Windows Server 2019, so connection details are good.

Any idea to help?

Thomas

mysql odbc windows-server-2019

3 Answers

  1. Best Answer

    It's quite possible MySQL is maintaining an internal DNS cache of hosts. For a quick and dirty test, try SET GLOBAL host_cache_size=0; on the server (if DNS load is a concern, remember to reset it to a non-zero value after testing).

    Edit: For a 5.5 MySQL try a FLUSH HOSTS;

    References: https://dev.mysql.com/doc/refman/8.0/en/host-cache.html#host-cache-flushing http://download.nust.na/pub6/mysql/doc/refman/5.5/en/dns.html

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  2. You can try to edit this file C:\Windows\System32\drivers\etc\hosts in which are stored all local DNS records. Also please check what is the answer of the current DNS server Windows uses, looks like it has a PTR record somewhere.

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  3. After loads of searches and precious help in the various comments, I eventually managed to solve the issue by executing a FLUSH HOSTS; SQL query within query editor on the remote server.

    See MySQL 5.5 documentation here.

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