Mailing List Archive

> when connecting to my PC over RealVNC via a modem
> (USB-stick from the provider Orange in Austria) I experience
> many interruptions. I have to reconnect almost every few
> minutes. This is the intrinsic to RealVNC because I do not
> get any interruptions when downloading large files from the
> same PC over hours by using the Filezilla Server and CoreFTP light.
> Is there anything I could do?

Sounds like your 3G connection is dropping, and taking VNC with it. This
could be due to network policy or poor coverage.

Have you considered establishing an SSH tunnel to an external server, then
VNCing through that? It's a little more involved, but not too difficult.
Bitvise Tunnelier is an excellent free application for managing SSH
connections (including setting up tunnels) and you don't require a licence
for individual use (although there's a 30 day trial period anyway regardless
of licence qualification). The more frequent SSH traffic may force the
connection to stay up if you're in a borderline reception area or your
network enforces a disconnect policy after traffic dips below a threshold.

Alternatively, have you tried doing something like establishing a constant
ping to a server whilst connected, to see if the regular traffic keeps the
connection alive?


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Hi Christopher,
thanks for the hints. I have indeed also tried SSH tunnelling
with even worse results (connection drops every several
seconds). The interesting point is that FTPing works without
drops (I downloaded a file from the same PC over 40 minutes).
This made me think that it must have to do with RealVNC. It
also does not seem to be the 3G connection that drops it looks
like if the VNC connection were somewhat shaky or unstable
when compared to FTP. I'll try the constant ping though and let
you know the results....
Dieter

On 8 Sep 2009 at 13:32, Christopher Woods wrote:

From: "Christopher Woods"
<christopher@custommade.org.uk>
To: <dieter.blaas@univie.ac.at>, <vnc-
list@realvnc.com>
Subject: RE: frequent interruptions when connected
over modem
Date sent: Tue, 8 Sep 2009 13:32:06 +0100
Organization: CustomMade Solutions

> > when connecting to my PC over RealVNC via a modem
> > (USB-stick from the provider Orange in Austria) I experience
> > many interruptions. I have to reconnect almost every few
> > minutes. This is the intrinsic to RealVNC because I do not
> > get any interruptions when downloading large files from the
> > same PC over hours by using the Filezilla Server and CoreFTP light.
> > Is there anything I could do?
>
> Sounds like your 3G connection is dropping, and taking VNC with it. This
> could be due to network policy or poor coverage.
>
> Have you considered establishing an SSH tunnel to an external server, then
> VNCing through that? It's a little more involved, but not too difficult.
> Bitvise Tunnelier is an excellent free application for managing SSH
> connections (including setting up tunnels) and you don't require a licence
> for individual use (although there's a 30 day trial period anyway regardless
> of licence qualification). The more frequent SSH traffic may force the
> connection to stay up if you're in a borderline reception area or your
> network enforces a disconnect policy after traffic dips below a threshold.
>
> Alternatively, have you tried doing something like establishing a constant
> ping to a server whilst connected, to see if the regular traffic keeps the
> connection alive?
>
>
> _______________________________________________
> VNC-List mailing list
> VNC-List@realvnc.com
> To remove yourself from the list visit:
> http://www.realvnc.com/mailman/listinfo/vnc-list
>


------------------------------------------------------------------------
Dieter Blaas,
Max F. Perutz Laboratories
Medical University of Vienna,
Inst. Med. Biochem., Vienna Biocenter (VBC),
Dr. Bohr Gasse 9/3,
A-1030 Vienna, Austria,
Tel: 0043 1 4277 61630,
Fax: 0043 1 4277 9616,
e-mail: dieter.blaas@meduniwien.ac.at
------------------------------------------------------------------------

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> thanks for the hints. I have indeed also tried SSH
> tunnelling with even worse results (connection drops every
> several seconds). The interesting point is that FTPing works
> without drops (I downloaded a file from the same PC over 40 minutes).

I'm not intimately familiar with Orange Austria's 3G setup, but it might be
that you're being QoSed off the network :( In the UK, T-Mobile actively port
filter/block on their base packages, and NAT all connections (even if you
request a static route - no static IPs available). If you upgrade to a
premium package, you get unfiltered ports, but the traffic is still heavily
QoSed.

If you ping a known good server for the duration of your connection, what is
your latency (and does the TTL constantly change?) There could be a dodgy
hop somewhere along your route.

This might also be a question for Orange to answer - I know that you can
request (on my network provider, at least) the facility for PPTP tunneling
enabled, which means that there must be some element of QoS applied to allow
business-grade tunneling to proceed without problems. Talk about overkill
for a VNC connection though! (If you Remote Desktop / RemoteAdmin in, does
it give you similar drops?)


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Dieter:

My guess for the reason that those FTP clients don't drop the
connection is that they automagically restore it when dropped.
If U try an FTP transfer using the command-line FTP client in
Windows, does the connection stay 'on,' or does it drop? That
FTP client is as simple as it gets, and is not likely to attempt
to re-connect a dropped session. OTOH, in my experience, most
not-so-simple FTP clients *will* attempt to re-connect.

Thx, Phil Long




-----Original Message-----
From: vnc-list-bounces@realvnc.com [mailto:vnc-list-bounces@realvnc.com]
On Behalf Of Dieter Blaas
Sent: Tuesday, September 08, 2009 8:56 AM
To: vnc-list@realvnc.com
Subject: RE: frequent interruptions when connected over modem

Hi Christopher,
thanks for the hints. I have indeed also tried SSH tunnelling
with even worse results (connection drops every several
seconds). The interesting point is that FTPing works without
drops (I downloaded a file from the same PC over 40 minutes).
This made me think that it must have to do with RealVNC. It
also does not seem to be the 3G connection that drops it looks
like if the VNC connection were somewhat shaky or unstable
when compared to FTP. I'll try the constant ping though and let
you know the results....
Dieter

On 8 Sep 2009 at 13:32, Christopher Woods wrote:

From: "Christopher Woods"
<christopher@custommade.org.uk>
To: <dieter.blaas@univie.ac.at>, <vnc-
list@realvnc.com>
Subject: RE: frequent interruptions when connected
over modem
Date sent: Tue, 8 Sep 2009 13:32:06 +0100
Organization: CustomMade Solutions

> > when connecting to my PC over RealVNC via a modem
> > (USB-stick from the provider Orange in Austria) I experience
> > many interruptions. I have to reconnect almost every few
> > minutes. This is the intrinsic to RealVNC because I do not
> > get any interruptions when downloading large files from the
> > same PC over hours by using the Filezilla Server and CoreFTP light.
> > Is there anything I could do?
>
> Sounds like your 3G connection is dropping, and taking VNC with it.
This
> could be due to network policy or poor coverage.
>
> Have you considered establishing an SSH tunnel to an external server,
then
> VNCing through that? It's a little more involved, but not too
difficult.
> Bitvise Tunnelier is an excellent free application for managing SSH
> connections (including setting up tunnels) and you don't require a
licence
> for individual use (although there's a 30 day trial period anyway
regardless
> of licence qualification). The more frequent SSH traffic may force the
> connection to stay up if you're in a borderline reception area or your
> network enforces a disconnect policy after traffic dips below a
threshold.
>
> Alternatively, have you tried doing something like establishing a
constant
> ping to a server whilst connected, to see if the regular traffic keeps
the
> connection alive?
>
>
> _______________________________________________
> VNC-List mailing list
> VNC-List@realvnc.com
> To remove yourself from the list visit:
> http://www.realvnc.com/mailman/listinfo/vnc-list
>


------------------------------------------------------------------------
Dieter Blaas,
Max F. Perutz Laboratories
Medical University of Vienna,
Inst. Med. Biochem., Vienna Biocenter (VBC),
Dr. Bohr Gasse 9/3,
A-1030 Vienna, Austria,
Tel: 0043 1 4277 61630,
Fax: 0043 1 4277 9616,
e-mail: dieter.blaas@meduniwien.ac.at
------------------------------------------------------------------------

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Dieter,

Filezilla and CoreFTP have very different traffic profiles from an interactive protocol like VNC.

The most likely cause of the issue you're seeing is that you're saturating the connection with input events, which can cause issues with very slow connections. Modern VNC Viewers provide an option to rate-limit pointer events, to work around issues of that sort.

Regards,

--
Wez @ RealVNC Ltd


> -----Original Message-----
> From: vnc-list-bounces@realvnc.com [mailto:vnc-list-
> bounces@realvnc.com] On Behalf Of Dieter Blaas
> Sent: 08 September 2009 12:57
> To: vnc-list@realvnc.com
> Subject: frequent interruptions when connected over modem
>
> Hi,
> when connecting to my PC over RealVNC via a modem
> (USB-stick from the provider Orange in Austria) I experience
> many interruptions. I have to reconnect almost every few
> minutes. This is the intrinsic to RealVNC because I do not get
> any interruptions when downloading large files from the same
> PC over hours by using the Filezilla Server and CoreFTP light.
> Is there anything I could do?
> Thanks, Dieter
>
> -----------------------------------------------------------------------
> -
> Dieter Blaas,
> Max F. Perutz Laboratories
> Medical University of Vienna,
> Inst. Med. Biochem., Vienna Biocenter (VBC),
> Dr. Bohr Gasse 9/3,
> A-1030 Vienna, Austria,
> Tel: 0043 1 4277 61630,
> Fax: 0043 1 4277 9616,
> e-mail: dieter.blaas@meduniwien.ac.at
> -----------------------------------------------------------------------
> -
> _______________________________________________
> VNC-List mailing list
> VNC-List@realvnc.com
> To remove yourself from the list visit:
> http://www.realvnc.com/mailman/listinfo/vnc-list


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