Nginx configuration for imap

Naresh V nareshov at
Mon Mar 22 09:52:55 EDT 2010

Bron Gondwana <brong <at>> writes:

> Why does the auth fail on the backend server?  It never should.  If it does
> that means you've screwed up pretty badly.  You can give the failure from
> nginx by just passing an Auth-Status header.

It fails on the backend server when the password that went in in the first place
is wrong.

I think nginx is at fault here since it considers the AUTHENTICATIONFAILED
response from the (dovecot) IMAP server as an invalid response.

2010/03/22 13:36:27 [info] 19575#0: *2 client <IP1> connected to
2010/03/22 13:36:34 [error] 19575#0: *1 upstream sent invalid response: "NO
[AUTHENTICATIONFAILED] Authentication failed."while reading response from
upstream, client:, server:, login: "email at",
upstream: yy.yy.yy.yy:143

(telnet session: 

* OK IMAP4 ready
a login email at wrongpassword
* BAD internal server error
Connection closed by foreign host.

Email clients such as thunderbird 3 or opera's M2 have trouble making sense of
such behaviour by nginx and don't even attempt to pop up the authentication
dialog box again.


More information about the Info-cyrus mailing list