samba - Mar 2009 - confused: when do I have to use \\DOMAN and when \\ip.address

Hi there,

I am (rather desperately, and failingly) trying to build a samba network.

I have a linux box woring as pdc. this machine is reachable as haydn.redcor.home
(or just haydn).
its domain name is ROTTI

then I have a suse box as a domain member. I could join it with
net join -U root%XXX -S haydn.redcor.home

now I would like to login into a shell with  smbclient
smbclient \\\\haydn\\robert -U robert works fine

but
smbclient \\\\ROTTI\\robert -U robert
does not. it producec the following error:
Connection to ROTTI failed (Error NT_STATUS_BAD_NETWORK_NAME


my question is now: when do i use the domain \\ROTTI (as I do in windows)
and when do I use \\url

thanks
robert