[Dovecot] DIGEST-MD5 doesn't work

[Jürgen Herz]

Hi,

my dovecot installation works since months and clients authenticate
using CRAM-MD5. But today I got the first chance to test an client that
supports DIGEST-MD5 - and it doesn't work. Because of lack of other
supporting clients and servers I'm now at the point I don't know which
side is to blame.

The error I get after the client answers the servers challenge is "-ERR
Authentication failed: Missing nonce parameter".
Though I don't know how DIGEST-MD5 works I wonder about the message
because the clients answer contains a nonce parameter (captured with
tcpdump):
YXV0aHppZD0ib3RycyIsY2hhcnNldD11dGYtOCxjbm9uY2U9IjFlOTZkYmZiZWEwZjUxNmVhZjEyYmM0NjU1M2JmZjVlIixkaWdlc3QtdXJpPSJwb3AzL25hbm8iLG5jPTAwMDAwMDAxLG5vbmNlPSJPVGpGWmhjS2FIVjZSVGMyZlRDTXJ3PT0iLHFvcD1hdXRoLHJlYWxtPSIiLHJlc3BvbnNlPTVmMTQyZWVlN2FmMWVmYTJhYWI5ZmM0ODNiOGJjOTJhLHVzZXJuYW1lPSJvdHJzIg==

authzid="otrs",charset=utf-8,cnonce="1e96dbfbea0f516eaf12bc46553bff5e",
digest-uri="pop3/nano",nc=00000001,nonce="OTjFZhcKaHV6RTc2fTCMrw==",
qop=auth,realm="",response=5f142eee7af1efa2aab9fc483b8bc92a,username="otrs"

Client is a Perl script using Net::POP3 and Authen::SASL Modules

Dovecot is version 0.99.14 - I know it's old and not supported. If one
tells me the bug is known and fixed in 1.0rc, then I'll think about
upgrading, but I just to test I don't want to change my running system.

Regards,
Jürgen