Samba 1.9.18.px nmbd problems

[Janne.Harju at nmp.nokia.com]

Hello

We caught bad Samba behaviour when we upgraded one Samba
server to version 1.9.18p3. nmbd started sending denial packets 
to PC's trying to release/refresh their group name <00>.

Here's the message from log.nmb:
validate_nmb_response_packet: Bad REG/REFRESH Packet. 
Ignoring response packet with opcode 8.

After this Samba started hosing:
process_name_release_request: Attempt to release name DOMAINNAME<00> 
from IP xxx.xxx.236.yyy on subnet xxx.xxx.238.zzz being rejected as 
it is one of our names.

This caused the PCs sending release/refresh packets 300 times per sec!
All the client PCs seemed to be old Windows 3.11 with FTP OnNet 
TCP/IP stack. Obviously our network was flooded. We had to shutdown 
Samba and revert back to 1.9.17p2.

Here are the relevant parts from smb.conf
  security = user
  domain master = no
  local master = no
  browse list = no
  preferred master = no
  wins proxy = no
  wins support = no
  dns proxy = no

"wins server = xxx.xxx.xxx.xxx" was not configured.

After this I checked couple of things with all 1.9.18px releases
in our lab. I've found out one thing so far:
 nmbd does not register group names <00> and <1E>
 if "wins server = xxx.xxx.xxx.xxx" is not configured

Is this correct behaviour? 
Has anyone experienced the same problem?

I'll be experimenting more tomorrow with the help of a network sniffer.

By the way, this behaviour reminds me very much of a similar problem
we had with the early version of Network Appliance's CIFS 
implementation. When PCs sent out name registration broadcasts NetApp 
replied with "OK" which caused shutdown of the PCs. If I recall 
correct it did also reply "OK" to name refresh/release packets. 
The PCs affected also had FTP OnNet TCP/IP stack configured.

Jeremy, are you sure you haven't gotten any code from NetApp? ;)

Regards,
 Janne Harju

System Analyst
Nokia Mobile Phones Ltd.
tel. +358 10 505 7143
email: janne.harju at nmp.nokia.com