Hi, I sent this post yesterday morning for a first time, but apparently Gmane ate it as it never showed up. I am reposting. All my apologies if you receive this port in duplicate. I tried to replace a Samba 2.2.7 PDC to a 3.0 transparently, and it did not work. For my explanation, we will call the Samba 2.2.7 PDC samba2, the new Samba 3 server samba3 and the domain DOMAIN. First, I migrate (by hand) all the users from samba2 to samba3; I copied smbpasswd, then cut-n-pasted the users and workstations account in /etc/passwd with vipw. Tested it, it seem to work well. At this point, samba3 is PDC for a temporary domain I called TEST. Then I retrieved the SID of DOMAIN by doing "net getlocalsid DOMAIN". Kept it for later. I shutted down samba2. I edited smb.conf on samba3 to set the same workgroup name, netbios name, various config and share definition. Restart Samba on samba3. Set the SID to the one previously retrieved with "net setlocalsid <SID previously retrieved>". Restarted samba3 again. Win9x clients worked correctly, no problems (as expected). NT-based clients complained about not finding the domain. I guessed I screwed up the SID change, so I copied secrets.tdb from samba2 to samba3 and restart Samba on samba3. It still did not work. Finally, I joined the NT-based clients by hand (fortunately, there was not many) and it worked. Since I have many Samba 2.2.x -> 3.0 PDC migration coming in near-term future, I was wondering what I did wrong and if there is a work around it. Is it possible to change a Samba PDC in a totally transparent fashion for the clients ? Are there any known issue doing it from Samba 2.2.x to 3.0 ? Thanks for your answer !