What on Earth is Session Zero?

James Weatherall jnw "at" realvnc.com
Tue Nov 1 23:10:14 2005


Stephen,

Looking at this more closely, your router configuration seems to be trying
to place both machines outside your router's firewall, which obviously can't
work.  With those rules, all traffic will go to 192.168.0.2 and 192.168.0.3
will never see any incoming connection attempts, if I understand them
correctly.

Please contact your router manufacturer for support for their product.

Wez @ RealVNC Ltd.


> -----Original Message-----
> From: vnc-list-admin "at" realvnc.com 
> [mailto:vnc-list-admin "at" realvnc.com] On Behalf Of Stephen
> Sent: 01 November 2005 19:22
> To: Steven D. Clark
> Cc: vnc-list "at" realvnc.com
> Subject: Re: What on Earth is Session Zero?
> 
> 
> ----- Original Message -----
> From: "Steven D. Clark" <sdclark "at" cnrgroup.com>
> To: <vnc-list "at" realvnc.com>
> Sent: Tuesday, November 01, 2005 3:53 PM
> Subject: Re: What on Earth is Session Zero?
> 
> > Does XP Home allow you to run "netstat -a" in a command window? You 
> > should see the following lines if VNC is listening:
> >
> >   TCP    <name-of-xp-box>:5800     <name-of-xp-box>:0       
>  LISTENING
> >   TCP    <name-of-xp-box>:5900     <name-of-xp-box>:0       
>  LISTENING
> 
> Yes it does. Below is my result from netstat -a on the XP 
> PC.This was after connecting it with "Add New Client" from 
> the remote end, and starting up Windows Media Encoder on Port 
> 8080. The RealVNC ports are 5920 and 5820. A Windows ME 
> computer (192.168.0.2 on the router also at the remote end) 
> uses Real VNC on 5900 and 5800 when it is on, and I CAN get 
> into to that one with RealVNC Viewer. The refusal to connect 
> on the XP PC I need (192.168.0.3 on the router at the remote 
> end) does not change whether the ME PC is on or off. The 
> router is configured to allow everything inbound to both as here:
> 
> Inbound Services
>  #  Enable  Service Name  Action  LAN Server IP address  WAN 
> Users  Log
>  1   Yes Any(ALL)  ALLOW always  192.168.0.2  Any  Always
>  2   Yes Any(ALL)  ALLOW always  192.168.0.3  Any  Always
>  Default  Yes  Any  BLOCK always  Any  Any  Never
> 
> netstat -a
> Active Connections
> 
>   Proto  Local Address           Foreign Address        State
>   TCP    YOUR-91C305C62F:epmap   YOUR-91C305C62F:0      LISTENING
>   TCP    YOUR-91C305C62F:microsoft-ds   YOUR-91C305C62F:0     
>  LISTENING
>   TCP    YOUR-91C305C62F:2869    YOUR-91C305C62F:0      LISTENING
>   TCP    YOUR-91C305C62F:5820    YOUR-91C305C62F:0      LISTENING
>   TCP    YOUR-91C305C62F:5920    YOUR-91C305C62F:0      LISTENING
>   TCP    YOUR-91C305C62F:8080    YOUR-91C305C62F:0      LISTENING
>   TCP    YOUR-91C305C62F:1028    YOUR-91C305C62F:0      LISTENING
>   TCP    YOUR-91C305C62F:netbios-ssn   YOUR-91C305C62F:0      
> LISTENING
>   TCP    YOUR-91C305C62F:1049    sptv.demon.co.uk:5500  ESTABLISHED
>   TCP    YOUR-91C305C62F:8080    sptv.demon.co.uk:1159  ESTABLISHED
>   TCP    YOUR-91C305C62F:8080    sptv.demon.co.uk:1174  FIN_WAIT_2
>   UDP    YOUR-91C305C62F:microsoft-ds   *:*
>   UDP    YOUR-91C305C62F:isakmp   *:*
>   UDP    YOUR-91C305C62F:1069    *:*
>   UDP    YOUR-91C305C62F:4500    *:*
>   UDP    YOUR-91C305C62F:ntp     *:*
>   UDP    YOUR-91C305C62F:1035    *:*
>   UDP    YOUR-91C305C62F:1900    *:*
>   UDP    YOUR-91C305C62F:ntp     *:*
>   UDP    YOUR-91C305C62F:netbios-ns   *:*
>   UDP    YOUR-91C305C62F:netbios-dgm   *:*
>   UDP    YOUR-91C305C62F:1900    *:*
> 
> 
> > ----- Original Message -----
> > From: "John Aldrich" <JAldrich "at" covista.com>
> > To: "'Stephen'" <stephen "at" sptv.demon.co.uk>; <vnc-list "at" realvnc.com>
> > Sent: Tuesday, November 01, 2005 8:16 AM
> > Subject: RE: What on Earth is Session Zero?
> >
> >
> > > Stephen:
> > > Are you running any antivirus software, such as "Norton Internet
> > Security"?
> > > There is sufficient anecdotal evidence that some 
> antivirus products
> > actively
> > > block VNC because they perceive it as "malware" due to 
> the fact that 
> > > it could be misused.
> > >
> > > The first thing I would try is to connect from your 
> Windows ME box 
> > > to
> your
> > > XP box and see if that works. If it doesn't, try the following: 
> > > Start ->Run ->Telnet <ip.of.xp.box> 5900 and see if you 
> get an "RFB" 
> > > prompt. If you don't, then your machine is
> not
> > > accepting connections. My XP Pro box appears to be having the same
> > problem,
> > > but I'm not blaming it on VNC, because it works fine on other XP 
> > > boxes. _______________________________________________
> > > VNC-List mailing list
> > > VNC-List "at" realvnc.com
> > > To remove yourself from the list visit: 
> > > http://www.realvnc.com/mailman/listinfo/vnc-list
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