ftp sessions fails with '421 Service not available' error.

Solution Verified - Updated -


  • None of the virtual users are able to login though ftp using the  vsftpd packages provided with RHEL5.4, login fails with the following error.
  • Updating vsftpd package in Red Hat Enterprise Linux 5 to vsftpd-2.0.5-16.el5 causes breakage in several FTP clients

For Example :

$ /usr/bin/ftp
Connected to (
220 (vsFTPd 2.0.5)
Name ( ftptest
331 Please specify the password.
421 Service not available, remote server has closed connection
Login failed.
  • The issue does not happen if it's traced using strace.


# strace -p $pid_of_vsftpd

The problem is back as soon as the vsftpd process  detached from strace.


  • Red Hat Enterprise Linux 5.4
  • vsftpd-2.0.5-16.el5 or later

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