The code that gets the client name from sessionsetup must be assuming that the hostname is ASCII, and if not converting the chars to underscores. For example, I have a Cyrilic hostname, and what it's connected via Samba, smbstatus shows the following: [root@ThunderBird tests]# smbstatus Samba version 3.0.10 PID Username Group Machine ------------------------------------------------------------------- 1081 mkaplan mkaplan ___________ (192.168.93.206) Service pid machine Connected at ------------------------------------------------------- public 1081 ___________ Fri Apr 15 12:36:53 2005 Note that my smb.conf has unix charset = utf-8