VNC server stops responding after a few days

[James Wheaton]

Hi everyone,

We've got a problem with RealVNC server which stops working after a few
days. A computer reboot is required to get it to work again. The error
message upon connecting is: unable to connect to host. 2 computers do
this on the regular and they have Windows XP installed. Is this a known
problem? Any idea what could be causing it?

[Paul Dunn]

Post by James Wheaton
Hi everyone,
We've got a problem with RealVNC server which stops working after a few
days. A computer reboot is required to get it to work again. The error
message upon connecting is: unable to connect to host. 2 computers do
this on the regular and they have Windows XP installed. Is this a known
problem? Any idea what could be causing it?

DNS lease timeout?

[James Wheaton]

The computer will work in other ways but not with VNC. It's set as
static IP, so the router should be giving the same IP after the lease
times out.

James Wheaton
FloSource, Inc.
Phone: [phone]
Fax: [phone]

Visit us on the web: www.flosource.com <http://www.flosource.com>

Post by Paul Dunn

Post by James Wheaton
Hi everyone,
We've got a problem with RealVNC server which stops working after a few
days. A computer reboot is required to get it to work again. The error
message upon connecting is: unable to connect to host. 2 computers do
this on the regular and they have Windows XP installed. Is this a known
problem? Any idea what could be causing it?

DNS lease timeout?
_______________________________________________
VNC-List mailing list
http://www.realvnc.com/mailman/listinfo/vnc-list

[Long, Phillip GOSS]

James:

Is your static IP address in the range of the router's DHCP
addresses? That won't work, because the computer, knowing that it
has a static IP, won't request a lease renewal, and after some
maximum amount of time, the DHCP server will try to force one.
What will happen in this case depends greatly on the software and
OS the computer is running, and on the behavior of the router. I'm
not a network guy, but I do know that unless your router is more
sophisticated than the average small-office router, static IP
addresses *MUST* be outside any range of DHCP addresses of your
router.

Thx, Phil Long




-----Original Message-----
From: vnc-list-***@realvnc.com [mailto:vnc-list-***@realvnc.com]
On Behalf Of James Wheaton
Sent: Monday, November 14, 2011 12:44 PM
To: vnc-***@realvnc.com
Subject: Re: VNC server stops responding after a few days

The computer will work in other ways but not with VNC. It's set as
static IP, so the router should be giving the same IP after the lease
times out.

James Wheaton
FloSource, Inc.
Phone: [phone]
Fax: [phone]

Visit us on the web: www.flosource.com <http://www.flosource.com>

Post by Paul Dunn

Post by James Wheaton
Hi everyone,
We've got a problem with RealVNC server which stops working after a few
days. A computer reboot is required to get it to work again. The error
message upon connecting is: unable to connect to host. 2 computers do
this on the regular and they have Windows XP installed. Is this a known
problem? Any idea what could be causing it?

DNS lease timeout?
_______________________________________________
VNC-List mailing list
http://www.realvnc.com/mailman/listinfo/vnc-list

--------------------------------------------------------

Goss ... Innovation for Business

NOTICE: This e-mail and any attachment(s) may contain confidential and proprietary information of Goss International Corporation and/or its subsidiaries and may be legally privileged. This e-mail is intended solely for the addressee. If you are not the addressee, dissemination, copying or other use of this e-mail or any of its content is strictly prohibited and may be unlawful. If you are not the intended recipient please inform the sender immediately and destroy the e-mail and any copies. All liability for viruses is excluded to the fullest extent permitted by law. Any views expressed in this message are those of the individual sender. No contract may be construed by this e-mail.

[James Wheaton]

Hi Phil,

The DHCP addresses go from 100 to 253 while the computers running VNC
have static IPs less than 100 (99, 98, and 97).

James Wheaton
FloSource, Inc.
Phone: [phone]
Fax: [phone]

Visit us on the web: www.flosource.com <http://www.flosource.com>

Post by Long, Phillip GOSS
Is your static IP address in the range of the router's DHCP
addresses? That won't work, because the computer, knowing that it
has a static IP, won't request a lease renewal, and after some
maximum amount of time, the DHCP server will try to force one.
What will happen in this case depends greatly on the software and
OS the computer is running, and on the behavior of the router. I'm
not a network guy, but I do know that unless your router is more
sophisticated than the average small-office router, static IP
addresses *MUST* be outside any range of DHCP addresses of your
router.
Thx, Phil Long
-----Original Message-----
On Behalf Of James Wheaton
Sent: Monday, November 14, 2011 12:44 PM
Subject: Re: VNC server stops responding after a few days
The computer will work in other ways but not with VNC. It's set as
static IP, so the router should be giving the same IP after the lease
times out.
James Wheaton
FloSource, Inc.
Phone: [phone]
Fax: [phone]
Visit us on the web: www.flosource.com<http://www.flosource.com>

Post by Paul Dunn

Post by James Wheaton
Hi everyone,
We've got a problem with RealVNC server which stops working after a

few

Post by Paul Dunn

Post by James Wheaton
days. A computer reboot is required to get it to work again. The

error

Post by Paul Dunn

Post by James Wheaton
message upon connecting is: unable to connect to host. 2 computers do
this on the regular and they have Windows XP installed. Is this a

known

Post by Paul Dunn

Post by James Wheaton
problem? Any idea what could be causing it?

DNS lease timeout?
_______________________________________________
VNC-List mailing list
http://www.realvnc.com/mailman/listinfo/vnc-list

--------------------------------------------------------
Goss ... Innovation for Business
NOTICE: This e-mail and any attachment(s) may contain confidential and proprietary information of Goss International Corporation and/or its subsidiaries and may be legally privileged. This e-mail is intended solely for the addressee. If you are not the addressee, dissemination, copying or other use of this e-mail or any of its content is strictly prohibited and may be unlawful. If you are not the intended recipient please inform the sender immediately and destroy the e-mail and any copies. All liability for viruses is excluded to the fullest extent permitted by law. Any views expressed in this message are those of the individual sender. No contract may be construed by this e-mail.
_______________________________________________
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http://www.realvnc.com/mailman/listinfo/vnc-list

[Christopher Woods (CustomMade)]

Post by Long, Phillip GOSS
Is your static IP address in the range of the router's DHCP
addresses? That won't work, because the computer, knowing
that it has a static IP, won't request a lease renewal, and
after some maximum amount of time, the DHCP server will try
to force one.
What will happen in this case depends greatly on the software
and OS the computer is running, and on the behavior of the
router. I'm not a network guy, but I do know that unless
your router is more sophisticated than the average
small-office router, static IP addresses *MUST* be outside
any range of DHCP addresses of your router.

FWIW, I've experienced pretty much set-and-forget behaviour from soho /
half-decent routers where you can assign a static IP and they'll respect the
assignation (or in the cleverer routers, you can fix a static lease). My
previous home Speedtouch TG585v7 could happily do this, as can the D-Link at
work. (Tomato which I use at home on a WRT54GL these days just ... Works.)

Surely if a machine has a fixed static IP, it doesn't even enter into
discussion with the network's DHCP server to request a lease? Just the usual
broadcast traffic...

[Paul Dunn]

Post by Christopher Woods (CustomMade)
Surely if a machine has a fixed static IP, it doesn't even enter into
discussion with the network's DHCP server to request a lease? Just the usual
broadcast traffic...

I'm not a networking or Windows expert, but this presumably depends on
whether the client (XP?) actually has the VNC server's IP address in its
hosts file (something like C:\WINDOWS\system32\drivers\etc\hosts). If it
doesn't, then it will send a request to get the address from the DHCP
server. If the client ends up using the IP address supplied by the
server, then it will eventually expire. I've had exactly this problem on
another X server (not VNC).

James: what's in your hosts file? And how does the client actually
connect to the server? What's the VNC command line?

[Long, Phillip GOSS]

Chris:

Again, I'm not a network guy, so YMMV. My experience has been that
the computer with the static IP address in the DHCP range of the
router will run with no immediate problems, but the DHCP server
will eventually revoke the lease (because nobody asks for it to be
renewed), then assign it to another computer. Duplicate IP
addresses are never fun to debug!

Thx, Phil Long




-----Original Message-----
From: vnc-list-***@realvnc.com [mailto:vnc-list-***@realvnc.
com] On Behalf Of Christopher Woods (CustomMade)
Sent: Wednesday, November 16, 2011 5:56 PM
To: Long, Phillip GOSS; vnc-***@realvnc.com
Subject: RE: VNC server stops responding after a few days

Post by Long, Phillip GOSS
Is your static IP address in the range of the router's DHCP
addresses? That won't work, because the computer, knowing
that it has a static IP, won't request a lease renewal, and
after some maximum amount of time, the DHCP server will try
to force one.
What will happen in this case depends greatly on the software
and OS the computer is running, and on the behavior of the
router. I'm not a network guy, but I do know that unless
your router is more sophisticated than the average
small-office router, static IP addresses *MUST* be outside
any range of DHCP addresses of your router.

FWIW, I've experienced pretty much set-and-forget behaviour from soho /
half-decent routers where you can assign a static IP and they'll respect
the
assignation (or in the cleverer routers, you can fix a static lease). My
previous home Speedtouch TG585v7 could happily do this, as can the
D-Link at
work. (Tomato which I use at home on a WRT54GL these days just ...
Works.)

Surely if a machine has a fixed static IP, it doesn't even enter into
discussion with the network's DHCP server to request a lease? Just the
usual
broadcast traffic...

--------------------------------------------------------

Goss ... Innovation for Business

NOTICE: This e-mail and any attachment(s) may contain confidential and proprietary information of Goss International Corporation and/or its subsidiaries and may be legally privileged. This e-mail is intended solely for the addressee. If you are not the addressee, dissemination, copying or other use of this e-mail or any of its content is strictly prohibited and may be unlawful. If you are not the intended recipient please inform the sender immediately and destroy the e-mail and any copies. All liability for viruses is excluded to the fullest extent permitted by law. Any views expressed in this message are those of the individual sender. No contract may be construed by this e-mail.

[James Wheaton]

The uncommented line in the hosts file is simply:
127.0.0.1 localhost

The default gateway is setup in the Windows IP properties (along with
the other static settings) to be 192.168.0.254, which is our
modem/router/DHCP server. The modem has an external static IP that we
would be connecting to with VNC. I can connect to it on that address and
the internal 192.168.0.99 ... The command line on the VNC Viewer
shortcut is just the default vncviewer.exe with no options.

I just woke up one of the VNC servers/desktops that stopped working over
the weekend. I opened the web browser and it took a bit to load; was it
asking for an IP renewal? Maybe it's just the power saving options that
are at fault:

Turn off harddicks: 1hr
Standby: 1hr
Hibernate: never

James Wheaton
FloSource, Inc.
Phone: [phone]
Fax: [phone]

Visit us on the web: www.flosource.com <http://www.flosource.com>

Post by Paul Dunn

Post by Christopher Woods (CustomMade)
Surely if a machine has a fixed static IP, it doesn't even enter into
discussion with the network's DHCP server to request a lease? Just
the usual
broadcast traffic...

I'm not a networking or Windows expert, but this presumably depends on
whether the client (XP?) actually has the VNC server's IP address in
its hosts file (something like C:\WINDOWS\system32\drivers\etc\hosts).
If it doesn't, then it will send a request to get the address from the
DHCP server. If the client ends up using the IP address supplied by
the server, then it will eventually expire. I've had exactly this
problem on another X server (not VNC).
James: what's in your hosts file? And how does the client actually
connect to the server? What's the VNC command line?
_______________________________________________
VNC-List mailing list
http://www.realvnc.com/mailman/listinfo/vnc-list

[Philip Herlihy]

I've missed a few episodes of this drama, so hope I'm not going over old
ground. I don't think you're doing enough to distinguish problems with VNC
server from general network problems. When the machine(s) are not
responding are you able to ping them? (You may need to "allow echo" on the
server firewall's ICMP tab, and you may be able to ping directly from the
router's diagnostic interface, if you can access that externally.) However,
you can test just as well with a VNC viewer on a machine on the same local
network. Is the network interface set to wake the machine if a connection
is made? Turning off standby might be a good option.

If you run ipconfig /all in a command window you'll see useful DHCP stats,
including the date/time any DHCP lease was obtained. For anything acting as
a server you're better off with a static IP (or a reserved DHCP address).
Reduce the DHCP range or "scope" to leave room at either end for a few
static IPs, and use one of those for this type of machine. Netscan.exe from
softperfect.com is a good free network scanner which might help you spot
issues.

You're not using wireless, are you? To be avoided if possible.

Check in Task Manager - if Peak Commit Charge becomes greater than Physical
Memory, the machine will have been paging out idle processes, and this might
include VNC server or maybe (?) networking components.


Philip Herlihy

-----Original Message-----
From: vnc-list-***@realvnc.com [mailto:vnc-list-***@realvnc.com] On
Behalf Of James Wheaton
Sent: 21 November 2011 14:50
To: vnc-***@realvnc.com
Subject: Re: VNC server stops responding after a few days

The uncommented line in the hosts file is simply:
127.0.0.1 localhost

The default gateway is setup in the Windows IP properties (along with the
other static settings) to be 192.168.0.254, which is our modem/router/DHCP
server. The modem has an external static IP that we would be connecting to
with VNC. I can connect to it on that address and the internal 192.168.0.99
... The command line on the VNC Viewer shortcut is just the default
vncviewer.exe with no options.

I just woke up one of the VNC servers/desktops that stopped working over the
weekend. I opened the web browser and it took a bit to load; was it asking
for an IP renewal? Maybe it's just the power saving options that are at
fault:

Turn off harddicks: 1hr
Standby: 1hr
Hibernate: never

James Wheaton
FloSource, Inc.
Phone: [phone]
Fax: [phone]

Visit us on the web: www.flosource.com <http://www.flosource.com>

Post by Paul Dunn

Post by Christopher Woods (CustomMade)
Surely if a machine has a fixed static IP, it doesn't even enter into
discussion with the network's DHCP server to request a lease? Just
the usual broadcast traffic...

I'm not a networking or Windows expert, but this presumably depends on
whether the client (XP?) actually has the VNC server's IP address in
its hosts file (something like C:\WINDOWS\system32\drivers\etc\hosts).
If it doesn't, then it will send a request to get the address from the
DHCP server. If the client ends up using the IP address supplied by
the server, then it will eventually expire. I've had exactly this
problem on another X server (not VNC).
James: what's in your hosts file? And how does the client actually
connect to the server? What's the VNC command line?
_______________________________________________
VNC-List mailing list
http://www.realvnc.com/mailman/listinfo/vnc-list