As far as I can tell, Koha::Z3950Responder doesn't support any form of authentication currently. I've played around a bit with the YAZ options but I haven't been able to get anything working there, so I assume it's up to the "Init handler" to handle authentication: https://metacpan.org/pod/Net::Z3950::SimpleServer#Init-handler I reckon we should look at adding authentication so that we can use the z3950responder in non-public ways.