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mburnside
Beginner
2,146 Views
Message 1 of 22

CGNAT and DDNS

Hi everyone,

 

Hopefully someone here can help with the problem I'm experiencing. I have a DDNS service and every now and again it totally drops off the Internet. Now this only seems to be the case with BT and Talk Talk at present. I have checked this against a friends Virgin media connection and the this remained active the whole of the test time. Under BT and Talk Talk (again tested by friends) the DDNS service simply won't follow the changes in IP addressing. This has even happened at certain times with BT, a lot of the time it seemed to happen on a Friday afternoon which seems even more puzzling. I confess I'm no boffin when it comes to this sort of thing but can safely say through about 3 months of testing and pulling out my hair the problem seems to be something with the actual ISP.

 

I've been reading a lot in to the CGNAT as of late and wondered if this could be the problem. To get access to my DVR I am using port forwarding on the router and obviously under a CGNAT the TCP protocol would not be supported?

 

If anyone can help it would be much appreciated. My DVR is not actually online at the moment so unfortunately I can't supply details for you lovely techy's to look at. I do however have this interesting page regarding the DDNS service I'm using.

 

http://www.intodns.com/dvrlink.net

 

Many thanks in advance.

 

M

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21 REPLIES 21
Distinguished Sage
Distinguished Sage
2,124 Views
Message 2 of 22

Re: CGNAT and DDNS

You can check here if you are on CGNAT and opt out.

http://btsupport.custhelp.com/app/answers/detail/a_id/44044/c/6433

 

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mburnside
Beginner
2,115 Views
Message 3 of 22

Re: CGNAT and DDNS

Thanks for the reply, I shall have a look at this later.

 

Does this sound like a possibility? The CGNAT thing was just the only thing I could find that may have been affecting it. I also read that this test is unreliable, someone actually said they were 100% on CGNAT due to the IP showing differently on the router to the whatsmyip check and this test still did not show as BT-CGNAT.

 

Any more thoughts are much welcomed.

 

M

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Distinguished Sage
Distinguished Sage
2,098 Views
Message 4 of 22

Re: CGNAT and DDNS

Thi image will give you some idea.

http://forumhelp.dyndns.info/networking/cgnat.jpg

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mburnside
Beginner
2,090 Views
Message 5 of 22

Re: CGNAT and DDNS

Not on a BT connection at the moment but any help is good. Thanks guys.

 

Could it possibly be the rubbish DNS servers of Bt that I'm also reading about? I'm clutching at anything with relevance here :'(

 

As always any help appreciated.

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Distinguished Sage
Distinguished Sage
2,082 Views
Message 6 of 22

Re: CGNAT and DDNS

I don't know what is causing the problem, but I doubt if it is CGNAT though as the problem would be there all the time.

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KennyMillar
Contributor
2,074 Views
Message 7 of 22

Re: CGNAT and DDNS

I too use a DDNS service and HH5

 

From time to time the incoming connections stop working, and though I check that my IP address is up to date, and the port-forwarding settings in the HH are correct, they just don't work.

 

The solution for me is the remove the port forwarding rule and add it back in again. 

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mburnside
Beginner
2,066 Views
Message 8 of 22

Re: CGNAT and DDNS

That's interesting to know Kenny, thank you for that, seems I'm not alone.

 

Thing with this is port forwarding every time you need the DDNS service is a bit of a pain. Out of interest which ports do you use and do you apply the port forwarding to a mac address or to a manually entered IP address?

 

The fact this happened on Talk Talk as well also puzzles me as that was a different router and service.

 

Any more info we all have lets get it posted, a thorough solution to this is just around the corner I'm sure it's something simple I'm just missing.

 

Regards

 

M

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Distinguished Sage
Distinguished Sage
2,059 Views
Message 9 of 22

Re: CGNAT and DDNS

When you get home, this link may help.

Port forwarding problems

 

Using a static LAN address outside of the DHCP range usually fixes the problem.

 

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KennyMillar
Contributor
2,055 Views
Message 10 of 22

Re: CGNAT and DDNS

I forward to a manually entered IP address, and my machine has a fixed IP address.

I'm using ports 80, 85 and 4002

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