ERROR 2027 (HY000): Malformed packet - during login

Question

C:\Program Files\MySQL\MySQL Server 5.7\bin>mysql -u root -p
Enter password:
ERROR 2027 (HY000): Malformed packet

I have 2 MySQL DBs version on my server 4.0 and 5.7. My apps can connect to both MySQL DBs without problem but when I try to login to the MySQL Command-Line Tool it is showing error as shown below. I also noticed even when I stopped the MySQL 5.7 service it is showing the same error but if I stopped the MYSQL4.0 service, it is showing:

ERROR 2003 (HY000): Can't connect to MySQL server on 'localhost' (10061)

Based on the some of the replies from similar topics, the malformed packet is because of the old password hashed issue but what are the things I need to do to change the password? Or my issue is not related with password?

FYI, I am using Windows Server 2012 R2. Mysql 5.7.21 and Mysql 4.0.17

Answer 1

It's compatibility issue between MySQL 5.7 client and MySQL 4.0 server.

My apps can connect to both MySQL DBs without problem but when I try to login to the MySQL Command-Line Tool it is showing error as shown below.

The reason may be simple, apps may be using diffrent version of Mysql connector API, e.g. App connect with v5.7 may be using 5.7 compatible liberary.

When you connect to MySQL 4.0, use MySQL 4.0 client and similar for MySql 5.7.

When you run both version simultaneously, make sure to specify the correct port.