[Box-Admins] Re: best practice RFB for Squeak-based server

[Chris Muller]

Thank you for these crystal clear instructions.  It worked.  :)


On Sun, Aug 28, 2016 at 5:44 AM, Levente Uzonyi <leves at caesar.elte.hu> wrote:
> Hi Chris,
>
> X forwarding and RFB/VNC are two entirely different things. Let's not mix X
> forwarding here.
>
> Squeak's RFB server and external VNC servers are also different things. They
> use the same protocol, but they work differently.
>
> If you use Squeak's RFB server, which is the preferred way IMO, then you
> don't have to use any external software. It's more responsive than an
> external RFB server, because it knows the rectangles which have changed, and
> it can use the same framebuffer as the image uses. It's only drawback is
> that Cmd+. will not always work, as it may interrupt one of the RFB server's
> processes.
>
> To set it up, just load the RFB package (I suggest you use this one for 5.1:
> http://leves.web.elte.hu/squeak/RFB-ul.14.mcz ), disable "allow remote
> connections", then start it on an unused port. The other default settings
> should be fine.
>
> How to choose the port?
> I prefer to keep RFB ports and Web ports in sync on a server. So if your web
> ports start from 8080 and RFB ports start from 5900 and let's say 8083 is
> free, then the RFB port 5903 should be used. When you start RFB, you have to
> pass the display number, which is RFB port minus 5900. So if you want the
> RFB server to listen on 5903, then you have to start it on display 3.
>
> How to connect to the RFB server?
> You have to forward the port via ssh from your local machine. For example if
> the RFB port is 5903, then when you connect to the server, you add the
> parameter
>
>         -L 5903:127.0.0.1:5903
>
> to the ssh command. Then you open your VNC client on your machine and
> connect to 127.0.0.1:5903. If your program uses display numbers you'll use
> display 3. Note that you can manage the tunnels of an existing
> connection[1].
>
> Some VNC clients don't seem to work well with Squeak's RFB server. You can
> make these work, by setting the encoding to ZRLE and the color space to max
> (24-bit).
>
> Levente
>
> [1]
> https://en.wikibooks.org/wiki/OpenSSH/Cookbook/Tunnels#Adding_or_Removing_Tunnels_within_an_Established_Connection
>
>
> On Sat, 27 Aug 2016, Chris Muller wrote:
>
>> Hi Levente and all, I unfortunately have only ever hobbled along with
>> "whatever I can get to work" when it comes to VNC.  It seems like it
>> always only barely works -- for example, using Squeak's RFB on on my
>> local laptop works fine viewing with Ubuntu's Remmina, but not the
>> commercial "vncviewer".
>>
>> On box4, I'm not sure what our viewer is, Xtightvnc?  Or, is that the
>> Xtight server because I know I've used a "xtightvncviewer" before...
>>
>> My strategy was to start RFB server in Squeak to accept local
>> connections only.  Then I was going to use ssh -X when I logged in to
>> box4 from terminal, and then, xtightvncviewer :6900.  Is this a flawed
>> strategy?  Your expertise could save me a lot of time from research
>> and trial and error by sharing your VNC best-practices with me.  :)
>>
>> When I tried Xtightvnc :6900, it said:
>>
>> =========
>> _XSERVTransSocketINETCreateListener: ...SocketCreateListener() failed
>> _XSERVTransMakeAllCOTSServerListeners: server already running
>>
>> Fatal server error:
>> Cannot establish any listening sockets - Make sure an X server isn't
>> already running
>> =========
>>
>> So yeah, Xtightvnc looks like a server, not a viewer, but I didn't
>> want to install xtightvncviewer without asking the box-admins team
>> leader first..
>>
>> Best.
>>
>