sync_client fails with GSSAPI error 'unknown mech-code 0 for mech unknown'

[Karl Pielorz]

Hi,

I've got my two 2.4.17 servers 'tantalisingly' close to replicating - I 
created a 'replication' user on both (using 'saslpasswd2').

This user is allowed 'admin' access (in imapd.conf). Additionally on the 
master I've set:

"
sync_host: my-replica-server.com
sync_authname: replication-user
sync_password: thepassword
sync_compress: 1
"

Running 'sync_client' on the Master though nets:

"
% /usr/local/cyrus/bin/sync_client -v -u user.kpielorz
Can not connect to server 'my-replica-server.com', retrying in 15 seconds
"

Syslog shows:

"
Jun  4 16:13:15 sync_client[37354]: GSSAPI client step 1
Jun  4 16:13:15 sync_client[37354]: GSSAPI Error:  An unsupported mechanism 
was requested (unknown mech-code 0 for mech unknown)
Jun  4 16:13:15 sync_client[37354]: couldn't authenticate to backend 
server: generic failure
"

The replica doesn't appear to log anything - we only use 'simple' 
saslpasswd2 authentication on the servers (no LDAP / database backend) - 
any suggestions on where to start looking to fix this?

Additionally in cyrus.conf we only bind imap to 127.0.0.1 - imaps/pop3s are 
used for off-host connections (in case that's an issue?)

Thanks,

-Karl