Connectivity
Connectivity and managing Your Comcast Business network
Male IT Specialist Holds Laptop and Discusses Work with Female Server Technician. They're Standing in Data Center, Rack Server Cabinet is Open.
Highlighted
New Member

Port Forwarding - Ports only open at certain times of the day. It makes no sense.

We have Comcast Business Internet and use the Cisco DPC3939B router.
 
We have an Amcrest video security camera system installed and have forwarded the correct ports and done the necessary configuration to get it working for external access. 
 
During the day (and also when there is activity happening on our internal network) you can access the security system remotely with no problems. Using various port checking tools I can also see that the ports are open and ready to go.
 
The problem is at night (also when no network activity is taking place) that the camera system becomes inaccessible. Using a port checking tool I can see that those same ports that were open a few hours ago are now closed. Nothing has changed and nothing has been shut down, etc. The tech from the camera system has looked at our configuration several times and cannot see what the issue is. Comcast support does not seem to understand or have a solution.
 
Any thoughts out there as to what could possibly be causing this?
0 Kudos
4 REPLIES 4
Highlighted
Trusted Forum Contributor

Re: Port Forwarding - Ports only open at certain times of the day. It makes no sense.

Hello byzantium and welcome,

 

First, if you are using a Comcast Static IP Address (CSIA) , then you should have simply logged into the DPC3939B user interface. go to Advanced, then click on port management and simply open the ports on the staticIP device address. If you are not using a CSIA, then you MUST make sure that you are NOT using one of the DHCP Server Dynamic Addresses (DSDA) between 10.1.10.2 through like 10.1.10.252. This is due to the Camera Server (CS) DSDA typically change every time the its DSDA expires. Therefore, you would need to change the DSDA start address from 10.1.10.2 to 10.1.10.10. This will provide you with non-changing 10.1.10.2 through 10.1.10.9 DHCP address to force feed its use for your CS and ONLY your CS. If you make any changes to you CS IP address, then go back into Advanced.Port Forwardinng and edit the IP address of the device you opened the ports originally on.

 

Lastly, it is MANDATORY that your CS is directly connected via ethernet cable to one of the LanPorts 1-4 on the back of the DPC3939B. If you follow the above afrorementioned  recommendations I have provided, your remote access to your CS should always be available.

 

Hope this helps you out. 

Highlighted
New Member

Re: Port Forwarding - Ports only open at certain times of the day. It makes no sense.

Wow - that's great advice. Would never have realized that and NO ONE I talked to at comcast even approached knowing that. I made those changes and assigned CS to 10.1.10.2 and made the necessary updates to assigned IP and port forwarding in the router. I will try it out later. Thanks again.

0 Kudos
Highlighted
New Contributor

Re: Port Forwarding - Ports only open at certain times of the day. It makes no sense.

I'm just guessing, but they probably did know and just didn't see how it could possibly fit in with your description of the problem.  It would be pretty strange for an addressing problem to show itself on a consistent day/night scehdule.  If the address changes didn't fix it... what happens on the weekends?

0 Kudos
Highlighted
New Member

Re: Port Forwarding - Ports only open at certain times of the day. It makes no sense.

After these changes the same problem persists...I can still can only externally access the  camera during the day. It simply times out at night. Using a port check too confirms that the port is closed. I can get a ping reply but the port itself is shut down. Perhaps I should try some different port numbers?

 

Port check done at 9am

4_2 port.JPG 

Port check done at 9pm

4_1 port.JPG

0 Kudos