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I'm having big trouble with my proftpd installation: the login is slow as hell, it takes about 10 seconds and more and that's to much for the default settings of most ftp clients. i'm using mysql and mod_sql as backend for the login.

I've already searched a bit and added the following to my proftpd configuration:

UseReverseDNS off
IdentLookups off
ServerIdent on “...”

But that did not help at all. Mysql is already set to not make any DNS lookups.

At the moment I have no idea, what to try next -- do you have any?

Thanks a lot!

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Maybe there is some invalid DNS entries in your interfaces config files? – Maxwell Jan 27 '10 at 9:15
thanks for your suggestion -- no ... the DNS entries are correct. i also thought, that proftpd should avoid any DNS lookups when specifying the above configuration options? – harald Jan 29 '10 at 10:19
up vote 1 down vote accepted

here's the answer for my problem:

apparently the SQLAuthenticate directive was the problem. it was set to:

SQLAuthenticate users userset

i've changed this to

SQLAuthenticate users

now authentication is fast as hell.

i've found a howto on the proftpd site, that explains why this configuration may cause problems:

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