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Trouble with port forwarding - Technicolor DPC3941B

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Trouble with port forwarding - Technicolor DPC3941B

New here, and I am hoping I'm on the correct forum, so here goes:

A client recently upgraded their Comcast Business Internet (which I guess required a different modem over the older SMC modem prior to upgrading ... and which I am much more familiar with).  The 'new' modem is a Technicolor DPC3941B, and as I explore the controls interface looking to establish port forwarding, it appears I'm not able to accomplish this properly

The 'app' we intend to use is called NetOp Remote Control and requires port 6502 UDP/TCP ('normal' but also assignable) to be 'port forwarded' to a statically assigned internal address in order to accomodate external traffic to reach the "gateway module".  This 'gateway module' then routes traffic to other internal PCs which also use port 6502 UDP/TCP.

In the past, I've normally statically assigned an internal LAN address to the network interface on the system operating the 'gateway module' (operating on a Windows Server 2012 R2 system) which has operated well in the past. All other internal devices are using DHCP issued from the modem/router, currently the 'new' DPC3941B

I've attempted to configure this on this 'new' Technicolor modem by doing as I always have done in the past, by simply assigning this port forwarding rule via IPv4 to the static address of the gateway device, but it appears that this does not seem to work.  Must I also configure IPv6 or is this actually something that only Comcast can accomodate?  I've seen some reference to this requirement on other sites, so just thinking I'll need to call Support and ask them to achieve the necessary 'forwarding'...

Or maybe I'm missing something here..?

Accepted Solution

Re: Trouble with port forwarding - Technicolor DPC3941B

FYI: as I continued to examine the DPC3194B, I noticed that the modem was not able to display any connected devices, either with DHCP addresses or static addresses. Considring this, I called Tech Support and explained my issues, which a 'soft' reset had no affect on, so the tech did a 'factory restore' on the device and after rebooting and operation restored, all LAN devices were then shown. After reinitiaing the port forwarding rule, I am now able to access our internal network. 

Issue has been resolved

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Community Manager
Community Manager

Re: Trouble with port forwarding - Technicolor DPC3941B

Welcome to our Business forums and thanks for taking the time to reach out to us. I would love to further assist with the port forwarding concerns. I have supplied a link here that will help you with the portforwarding options for our services and help you to get that provisioned on the modem. concerns. https://business.comcast.com/help-and-support/internet/comcast-business-ip-gateway-static-firewall/.... As far as the IPV6 is concerned all provisioning is done on the customer side here is another link that will help you with any information on that as well. https://business.comcast.com/help-and-support/internet/comcast-business-internet-learn-about-ipv6/. I am happy to assist with any further questions or concerns that you may have, please reach out through private message with your first and last name, the full service address and account number or phone number and we will get started. -Comcast_Michelle

Re: Trouble with port forwarding - Technicolor DPC3941B

I accessed the link you had attached and printed out this information as a guide.  This very closely follows what I have done many times before, but in this case, with no success.

Here is what I did:

1. I defined a Port Forwarding rule within the 'Advanced' menu in the DPC3941B and configured this rule with the name I chose (ie: NetOp), then I entered the static IPv4 internal IP address of the computer I'm attempting to access (10.1.10.250).  I also configured the port range within this rule (which in the case of NetOp is solely port 6502) and the protocols required (UDP/TCP) and saved this rule.

2. I then limited the scope of the DHCP server in the DPC3941B so that this statically assigned address was not within the DHCP server range and saved this configuration (literally, I limited the DHCP scope to use only 10.1.10.2 - 10.1.10.125 insofar as there are less than 15 devices connecting to the LAN or the wifi which would implement DHCP from the LAN and DHCP server).

3. Lastly, I statically assigned the IPv4 address assigned to this rule to the Ethernet interface on the computer running the gateway software and verified a valid connection. (in essence, saving this configuration within Windows).

NOTE: I did not configure "Static IP port management" from within the modem's control pages, but ostensibly I possibly should have done this also insofar as all attempts to connect by accessing the public IP address of the Comcast system (by using the associated software caled "NetOp Guest"), but this does not then establish a connection to the NetOp 'gateway' system software as I would normally expect under previous scenarios.  It was for this reason I asked about the necessity of IPv6 configuration for this rule, as well.

Of some small note, it is not possible to "browse" for an attached PC when assigning port forwarding or when I examined the 'static port managment' configuration page. When I attemtped this, no devices attached to the LAN appear when "browsing" for an attached device.  This was also one reason that I had mentioned that I might need to contact Comcast Support to see if there were any 'rules' on the "server-end" which potentially only they coudl access that needed to have assigned ports and protocols so they are 'open' and accessible..

 

Community Manager
Community Manager

Re: Trouble with port forwarding - Technicolor DPC3941B

Thank you so much for taking the time to reach back out to us with the updated information and steps that you have taken. If you have followed the steps within the guide that I have supplied and it is still not working then at this point there is something with the configuration of your equipment or the manner in which you set up the port-forward that is the issue. This is not something that I would be able to assist with as this is something that is outside of the demarcation point of our services. If you have any further technical issues I would love to assist please reach out through private message with your first and last name, full service address and account number or phone number? -Comcast_Michelle

Re: Trouble with port forwarding - Technicolor DPC3941B

FYI: as I continued to examine the DPC3194B, I noticed that the modem was not able to display any connected devices, either with DHCP addresses or static addresses. Considring this, I called Tech Support and explained my issues, which a 'soft' reset had no affect on, so the tech did a 'factory restore' on the device and after rebooting and operation restored, all LAN devices were then shown. After reinitiaing the port forwarding rule, I am now able to access our internal network. 

Issue has been resolved

Community Manager
Community Manager

Re: Trouble with port forwarding - Technicolor DPC3941B

I am so very glad to hear that you were able to get this resolved. If you need anything further please don't hesitate to reach out to us at any time we would love to assist should you need us again. -Comcast_Michelle