wierd logon problems (An explanation?)

[James B Curry]

The following are log.username files from two different Samba server
logs.  One is from my network, one is from Brian's.  We both are
receiving the message "domain password not correct or access to domain
server has been denied" when our users attempt to logon, and see the
following entries in our log.username files:

<log.myuser>
[2000/11/01 08:45:07, 0] lib/util_sock.c:write_socket_data(537)
  write_socket_data: write failure. Error = Broken pipe
[2000/11/01 08:45:07, 0] lib/util_sock.c:write_socket(563)
  write_socket: Error writing 4 bytes to socket 6: ERRNO = Broken pipe
[2000/11/01 08:45:07, 0] lib/util_sock.c:send_smb(751)
  Error writing 4 bytes to client. -1. Exiting

<log.briansuser>
[2000/10/24 13:03:22, 0] lib/util_sock.c:write_socket_data(570)
  write_socket_data: write failure. Error = Broken pipe
[2000/10/24 13:03:22, 0] lib/util_sock.c:write_socket(596)
  write_socket: Error writing 4 bytes to socket 7: ERRNO = Broken pipe
[2000/10/24 13:03:22, 0] lib/util_sock.c:send_smb(784)
  Error writing 4 bytes to client. -1. Exiting

Can anyone decipher what these error messages mean?
What is failing and what would cause it to fail?
 
In both cases, the users that have already logged on have no problems
using the Samba shares.  The users that experience these logon errors
are eventually able to logon successfully.  In my case, this has only
happened once for 30 minutes.  In Brian's case, it happened daily.  He
decided to quit logging on to the domain and just map the drives like a
workgroup.  Since he doesn't have them log on, his users are now able to
use the Samba shares without any problems, but he still gets the broken
pipe errors in his log.username files.

We are both suspecting network errors (collisions?) are the cause, but
why does it only affect the domain logon and no other network services? 
Is there a low timeout threshold for domain logons that could be
affected by packet collisions or other network problems?

I should note that I originally believed this to be a corrupt smbpasswd
file, as the problem disappeared seconds after I changed a user's
password.  Coincidental, or is it possibly related?