Problem with Vivotek cameras behind NAT

[mountain_lion]

I have combination of different Vivotek IP camera models some static and some with Pan & Tilt control on a private network, each with own static IP. Web interface differs slightly between the PT and static camera models.

Connection to the internet is via ADSL router set up to do NAT, with port forwarding to allow access to the cameras from the internet.

e.g.
mydomain.co.za:8080 => camera A (static cam)
mydomain.co.za:8081 => camera B (PT cam)
etc

From the internal private network direct connections to the 192.168.0.x IPs are used.
No problem here.

At first it seemed that everything worked from the internet too, including PTZ control.

Browser is IE8; not my first choice, but IE works better with the Vivotek web interface.

However, IE does some strange caching when connecting from the internet via the port forwards.
After connecting to static cam A, the PTZ controls for camera B stops working until I clear the browser cache.
If I connect to cam B first then all works 100%, until I connect to cam A.

Seems like IE caches the web interface for the domain name irrespective of the port and somehow it prefers the web interface of the non-PTZ camera.
From the private network where a unique IP address is used for each camera, the problem is avoided.

Is my conclusion of what is happing here correct?
Any workaround for this other than clearing the browser cache every time when connection from the internet?

 

[Telasera]

Hi mountain_lion,

This problem does sound annoying, have you tried to create a cname records for the second IP cam as IE might not perform caching if setup like that. Its worth a try.. something like this mydomain.co.za:8080 / cam2.mydomain.co.za:8081

Alternatively is there not software that you can use from Vivotek to remotely view and manage the cameras so you can avoid the web interface or is that what you prefer?

 

[Q-Tech]

Hi mountain_lion,

I think Telasera may have the solution above, otherwise (If it's an option for you), why not put a cheap pc on the 192.168.0.x network, port forward/nat the pc's address, use teamviewer or mstsc to remote into the pc and run the browser from there to manage the cameras.

 

[mountain_lion]

Thanks for the replies.

The whole idea of having a web server on the cameras is to avoid a PC running 24/7.

While the cname approach should work, it is problematic to implement because the public IP is dynamic. At present the router's DDNS function is used to keep the IP updated on DynDNS, but only one DNS entry can be handled. To do more than one entry would also require a PC running a client.

Seems like I am stuck with clearing the browser cache or having a PC running on the internal network or paying for a static IP.

 

[GarethY]

Just a hunch, but what happens when you call the urls like this?

mydomain.co.za:8080/?1
mydomain.co.za:8081/?2

 

[Q-Tech]

Hi mountain_lion,

I had another thought on this - what happens if you use the "InPrivate Browsing" option on IE8 - CTRL-SHIFT-P opens a new window which 'supposedly' doesn't cache anything from the session. An extra step, but might save some time in the long run.

 

[mountain_lion]

using
mydomain.co.za:8080/?1
mydomain.co.za:8081/?2
does not help, but InPrivate Browsing is a good idea and does work; thanks!

Can IE be set to always use InPrivate Browsing or not cache at all or to exclude certain sites from caching?

I only use IE for the cameras due to the ActiveX requirement. Else I use Firefox or Chrome.

 

[Q-Tech]

I just tested this and it works perfectly :

Create a new shortcut on your desktop with a command line that looks like this :

"%ProgramFiles%\Internet Explorer\iexplore" -private

Just use that shortcut to start IE instead of the usual one and away you go - you might even be able to put the URL for the camera in the command line somehow - you can google that bit

 

[mountain_lion]

Thanks Q-Tech

Still not sure exactly what is happening here.
My 1st test using in-private browsing did not break the PT control, but now it is broken again while using in-private...

Will Google some more.

 

[mountain_lion]

Sorry Telasera; I must have been half asleep when I read & replied to your post regarding using cnames.

Of course that makes perfect sense!
Tried it after the penny finally dropped, and that does the trick. Works 100%
Thanks!

So the issue here is browser caching when using one hostname with different ports.
I now have a cname for each camera type and this works around the caching issue.
As before the port numbers and forwarding directs the traffic to the appropriate camera.

 

[Telasera]

Happy to help Mountian_lion