[SOLVED] Cannot join PDC Nethserver domain

hi there.
because of our Sophos UTM, I couldn't join a workstation on 10.0.1.x to the domain on 10.0.0.x.
My NS IP is 10.0.0.200, former working ldap server was 10.0.0.2
I created a policy allowing ports 389 (ldap) and 445 (microsoft-ds) from 10.0.1.x to 10.0.0.200.

netstat -a | grep mydom
myserver.mydom:microsoft-ds
myserver.mydom.lan:ldap
    
cat /etc/services | grep microsoft
microsoft-ds    445/tcp
microsoft-ds    445/udp

cat /etc/services | grep ldap
ldap 389/tcp
ldap 389/udp

Now the workstaton joins the domain.
The workstation was patched with registry key mentioned by @Nas
I have also modified c:\windows\system32\drivers\etc\hosts with

10.0.0.200 mydom.lan    myserver.mydom.lan

Thank you all.
Cheers.