Can not view DVR through a specific ISP... why?

[TomSmithery]

We have a HIK DVR setup at my shop with ISP A
The following ports are open and verified open via: Open Port Check Tool - Test Port Forwarding on Your Router
http: 80
rtsp: 554
server: 8000

Using any app on our phones, we can connect and view the cameras no problem.
At home we try to connect using the same ISP provider as the shop, ISP A... via Internet Explorer, but we can NOT access the DVR. Luckily I have a second ISP, ISP B at the house as a backup... I connect the exact same laptop to ISP B and just refresh Internet Explorer, and it connects fine and I can see the cams.

I contacted ISP A to verify ports 80, 554, 8000 are not being blocked... they said they are not. Just in case, I went to www.grc.com and used the ShieldsUp to see if the ISP A was blocking the ports at my house... they came back as fine.

I thought that MAYBE the router I have for ISP A is causing the problem... I went to a neighbors place who has the same ISP A, but a totally different router.... and nope, he can't connect to my DVR IP either.


Anyone have any clue as to what the issue is?
Thanks all!

 

[fenderman]

stop port forwarding... that DVR will be hacked...
It's most likely related to the http Port being said the 80... If you change it to something else it should work... With a DVR the mobile app only uses the media port and the rtsp port....

 

[TonyR]

Did someone forward the ports in the non-working router for ISP A to be the same as the ports forwarded in the working router for ISP B?
In other words, are both routers configured identically with regards to port forwarding?

 

[looney2ns]

Stop all port forwarding today!
Search here for VPN primer for Noobs.

 

[alastairstevenson]

Just in case, I went to www.grc.com and used the ShieldsUp to see if the ISP A was blocking the ports at my house... they came back as fine.

That's inbound to your house - not inbound to the shop, so not relevant.

In any case - take strong heed of @fenderman and @looney2ns good advice - after you think about what is of value to you on the shop network.
Data to be breached, data to be ransomed / encrypted, malware to be placed etc etc.
You are taking a big risk by allowing the entire internet into your shop network.