ubuntuforums-unanswered team mailing list archive

[LEGOManiac <question78960@xxxxxxxxxxxxxxxxxxxxx>]

Question #78960 on Ubuntu changed:
https://answers.launchpad.net/ubuntu/+question/78960

    Status: Answered => Open

LEGOManiac is still having a problem:
Within a Windows system, there is the computer browser service. You can
see it by typing:

Start->Run->services.msc

and then looking for "Computer Browser".

This is a service associated with NETBIOS to keep track of all the other
computers running NETBIOS a given Windows computer sees on the local
network. When a Windows PC starts up, it sends a broadcast out on the
network, to all computers, telling them what it's system and workgroup
names are.

Unfortunately, the service name, "Computer Browser", is a bit
misleading. It implies that it allows your computer to browse the
network as a web browser allows you to browse the internet. This is not
the case. The Computer Browser service is actually a cache of computers
that are seen on the network. As such, it's more of a server than a
browser in the literal sense.

Microsoft had a problem when they invented this: what happens to the
computer that just joined the network? It hasn't "seen" any broadcasts
from the other computers on the network yet, although it has let them
know that it as just joined. Microsoft's solution to this has caused
problems for decades.

While, by default, all Windows computers have the Computer Browser
service running automatically, initially at least, only the first
computer started actually has a full list of computers on the network,
each one being added as they individually start up. This first computer
is called the Master Browser. While each Windows computer on the network
has the Computer Browser service running, they in fact all use the
Master Browser's cache when searching the network. This is why, in a
Windows network, it's important to start the computer you want to be the
Master Browser first and then only start the other PC's after the Master
Browser is running. It's also why shutting down the Master Browser plays
havoc on the local network. It is therefor good practice to stop the
Computer Browser service and set it to manual startup on all Windows
computers on a local network, except the one you want to use as the
Master Browser. Usually, this is the computer you would leave running,
or use most often. It my case it's my file server.

There is one further wrinkle. If the Master Browser becomes
disconnected, another computer that has the Computer Browser service
running will become the Master Browser. This becomes a problem when the
first Master Browser comes back. There should only ever be one. In this
case, with two Master Browsers, you can have  a condition like I
described in my original post: namely, that one computer sees one set of
computers available, while another computer sees something a bit
different.

The fact that my XP pc sees only my server but the Ubuntu PC sees both
the server and the laptop that was switched off 45 minutes earlier is
what made me wonder if the Ubuntu PC had become it's own Master Browser,
with it's own cached set of networked computers.

The bottom line is I really don't know how Samba works under the covers.
Obviously, it can use NETBIOS to connect to Windows PCs, but does it
also cache what it sees, and if so, how do you force it to use only the
Master Browser (my file server) instead of it's local cache.

The fact that restarting Ubuntu lost the laptop would seem to confirm my
suspicion that Samba is keeping a cache.

As I write this, I had an idea. I tried "sudo service samba stop" but
was told that there is no such service.

I tried "sudo service --status-all but samba isn't in the list of
running services.

OK. So, I was under the impression that Samba was responsible for file
sharing in a Windows environment, but perhaps it's someting else (if so,
what?) but either way, I'm still trying to find out how to fix this
computer browsing and apparent caching problem.

-- 
You received this question notification because you are a member of UF
Unanswered Posts Team, which is an answer contact for Ubuntu.