C7800 Port Forwarding not working

C7800 Port Forwarding not working

SheepDog1813
Tutor

C7800 Port Forwarding not working

This post is actually in reference to the Netgear C7800 Cable Modem/AC Router however I couldn't find it to select in the post drop-down list.

 

It seems I am unable to forward ANY ports for some reason and was wondering if anyone may be experiencing the same problem.  

 

I apologize in advance for my overuse of capitalization but I do so only for clarity. So here is an example of the strange behavior I'm getting. At this point, let's assume NO ports have been forwarded. On my local network, if I want to access a local webserver (an ip camera for example), I can manually enter the assigned IP: PORT which I’ve set up through the device itself. It loads with no problem. Now let’s try to forward the required port after setting a static IP on the router (or in the device settings, whichever) in preparation for accessing externally. Now, I suddenly lose the ability to get to the page using IP: PORT, HOWEVER I CAN get to it via my dynamic DNS which I’ve got set up through Noip.com (noip from here on out). Now keep in mind, this is local on my own network. So, no connection via IP: PORT but I can connect via NOIP: PORT. In essence, if I’m thinking about this correctly, it’s using my external IP with the specified port to access it within the local network.  When the same is attempted off-network (NOIP: PORT), there is no access and the request times out. Port checking websites show that the port, which should be forwarded, is closed. I was thinking that maybe its a NAT loopback issue (not sure that the C7800 supports it), but that almost doesn’t make sense either.

 

Here’s the rub though, I believe everything concerning the ports worked fine initially when I first got the Modem/Router but it was at a time right before I moved and I’m just now getting around to setting my devices back up. I had migrated from a Comcast issued Arris cable modem and  a ASUS RT-AC68U router shortly before the move - to my recollection, everything worked after transferring the settings over.

 

I also did the following before I realized I was having issues but I don’t know if it’s just a coincidence or if this somehow broke something. So initially, my DCHP was set to give addresses in the range from 192.168.3.100-254. Prior to realizing any issues, I expanded the DCHP to 192.168.3.5-254 allowing a few open IP’s free to assign outside of the range of the DCHP server. That’s when I noticed the problem. I’ve since expanded the DCHP to 192.168.3.2-254.

 

A couple of things to note. If I enable uPnP on the router and the ip camera, it works just fine. I can access the ip camera using IP: PORT locally and NOIP: PORT externally. I did notice in the uPnP table, that along with the port set up in the camera settings, port 0 (zero) was also listed (twice, but I don’t recall details on the difference between the two entries). Also, the assigned external ports used for remote router administration work. I can access the router settings via the router IP locally and via NOIP: PORT externally (both by http and https with the two different ports). Those ports are specified on the Remote Access page of the router settings however and not on the port forwarding page. An open port check on an outside network shows that the ports are open as well. Just none of the ports set up on the Port Forwarding/Port Triggering page. Though it’s great that uPnP works, it doesn’t really help me though since most of the devices I need access to are not uPnP and I’d prefer not to use it anyway on general priciple. I’ve since turned that setting back off.

 

Any idea on what’s going on here before I just break down and do a factory reset?

Model: D7000|Nighthawk AC1900 VDSL/ADSL Modem Router
Message 1 of 12
11 REPLIES 11
antinode
Guru

Re: C7800 Port Forwarding not working

> [...] I can manually enter the assigned IP: PORT which I've set up
> through the device itself. It loads with no problem. [...]

   This whole thing would be _much_ clearer if you showed actual port
numbers, IP addresses, URLs, and so on, instead of all this vague
hand-waving stuff.  You're allowed to hide your public IP address, but
any other details should be exposed.  This includes showing your actual
port-forwarding rules, address reservations, and so on.  Copy+paste is
your friend.

> [...] after setting a static IP on the router (or in the device
> settings, whichever) [...]

   A static address is configured on the device itself; a reserved
dynamic address is configured on the router (DHCP server).  Which are
you using?

> [...] uPnP and I'd prefer not to use it anyway [...]

   UPnP should not be needed.  I, too, would avoid it.

> [...] before I just break down and do a factory reset?

   Feel free, but I wouldn't expect doing the same configuration again
to yield a different result.

Message 2 of 12
SheepDog1813
Tutor

Re: C7800 Port Forwarding not working

I apologize for being vauge, the only reason I didn't provide specific ports was because none of them seem to be forwarding. Ill go ahead and give you a couple of examples, I use 192.168.3.111 for one of my ip cameras. This is set up as reserved in the router with port 9111 designated in the camera as the port. My port forwarding rule is simply 9111 external to 9111 internal mapped to 192.168.3.111. As another example, I'm running Home Assistant on a Rasberry Pi3B connected to a LAN port. At first I used a reserved address of 192.168.3.3 until I decided to set a static IP (same address). The port is 8123. Again, just a simple 8123 external to 8123 internal mapped to 192.168.3.3. I have also attempted to forward external port 80 to internal 8123 for Home Assitant (192.168.3.3), but that got me no where as well.

 

Once I forward any port which has a device set up and listening on that port, I lose local access through the IP: PORT and can only access it via dynamic DNS: PORT and cannot access externally at all. Yet, as stated, uPnP seems to work ok and the ports designated on the router remote administration page still work; example 8080 for http.

 

 

Message 3 of 12
antinode
Guru

Re: C7800 Port Forwarding not working

> [...] a couple of examples, [...]

   That all sounds reasonable (except the results).

> Once I forward any port which has a device set up and listening on
> that port, I lose local access through the IP: PORT and can only access
> it via dynamic DNS: PORT and cannot access externally at all.

   I've never touched a C7800, so I know nothing, but in my limited
experience, I've never seen a router where creating a port-forwarding
rule had any effect on LAN access to the relevant server.  Similarly,
around here, if <public_IP_address>:<external_port> works at all, it
works from the LAN and the outside world.  (Where "around here" means a
variety of DSL modem+router models, currently a D7000[v1],
V1.0.1.64_1.0.1.)

   For example, I have a camera with a reserved address and a
port-forwarding rule:
      11        cam1    TCP     5601-5601       88-88   10.0.0.113

   I can access that camera from a LAN system at 10.0.0.113:88 or
<my_public_IP_address>:5601.  (I can't easily test it at the
moment, but I'd bet on the second one working from the outside world,
too.  It has worked in the past.)  UPnP has always been disabled here.

   A cable-TV modem(+router) does leave your firmware at the mercy of
your ISP, so that's not open to easy experimentation.  If you could lay
hands on a simple cable modem (or the C7800 configured as modem-only?)
and a separate router, then you could run some experiments using a (more
trustworthy?) router over whose firmware you'd have more control.

> [...] was wondering if anyone may be experiencing the same problem.

   Other than official Netgear support, another C7800 user may be the
best hope.

Message 4 of 12
vkdelta
NETGEAR Expert

Re: C7800 Port Forwarding not working

which FW?

Message 5 of 12
SheepDog1813
Tutor

Re: C7800 Port Forwarding not working

V3.01.36

 

I Know Comast has  a newer one but it hasnt been pushed yet. Whenever Ive calld in the past to ask them about pushing the newer one, they literally have no clue what I'm talking about. Figure it's not worth spending 8 hours on the phone trying to get to someone that actually could help me.

Message 6 of 12
SheepDog1813
Tutor

Re: C7800 Port Forwarding not working

Thank you and yes, Ive never seen that behavoir either. Its just downright bizarre.I'm thinking I'm just going to reset and start from scratch and see if that helps. If not, someone may be getting a really, really good deal on a C7800 on eBay.

Message 7 of 12
vkdelta
NETGEAR Expert

Re: C7800 Port Forwarding not working

pls PM me .. 

Message 8 of 12
SouthernFried
Aspirant

Re: C7800 Port Forwarding not working

Having the same problems as SheepDog.

 

C7800 with V3.01.36 firmware and trying to forward 443 to a VPN firewall inside my network. The router log doesn't show any attempts to access the forwarded port. Verified the problem doesn't involve the VPN firewall by connecting to it while on router's network.

 

Other things I've tried but not successful:

- Disabling the router's firewall.

- Putting VPN firewall in DMZ -- with and without firewall enabled.

Message 9 of 12
SheepDog1813
Tutor

Re: C7800 Port Forwarding not working

I resorted to doing a factory reset and it solved the port forwarding issue, plus I think it triggered a firmware update (the firmware was updated within about 24 hours after the reset but I'm not sure if its a coincidence). The weird behavior with not being able to access devices locally via IP: PORT is still happening though.  Netgear support has reached out to me though and hopefully they'll come up with a solution.

Message 10 of 12
SouthernFried
Aspirant

Re: C7800 Port Forwarding not working

I tried to connect to VPN over cellular internet and was able to connect. Nothing changed since yesterday, which was the first day having the C7800. Firmware rev is the same and didn’t do factory reset.

 

Sorry but I can’t replicate the issue you’re having connecting to the IP:Port of the forwarded device via local network connection. Weird indeed.

Message 11 of 12
WafflesMcDuff
Aspirant

Re: C7800 Port Forwarding not working

I was having this problem too. I did as suggested and reset to factory settings. It immediately triggered a firmware update which fixed the problem. Thanks!
Message 12 of 12