TD-W8970 NAT issues

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TD-W8970 NAT issues

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TD-W8970 NAT issues
TD-W8970 NAT issues
2013-05-31 16:28:55
Region : UnitedKingdom

Model : TD-W8970

Hardware Version : V1

Firmware Version : 130415

ISP : Plusnet


Hi,

I recently purchased a TD-W8970 to replace the ropey Thompson modem that Plusnet provide and I'm having a few issues configuring or working with NAT.

Firstly I'd like to find out if NAT is enabled when using the PPPoA WAN interface, there is no option to turn it on in the interface settings, making me think it may not even be supported, and the interface documentation isn't particularly clear about features not mentioned in each specific interface's settings.

Secondly, if NAT is enabled, is it slightly iffy? I have desktop machines that can reach other machines using just their network name, but none of the android mobiles/tablets I have can reach any of the machines other than by IP address.

So, am I being a little impatient and this situation will resolve itself? Maybe at the next DHCP refresh, and all the devices will be able to connect via name rather than just ip?

Or, is this something I can just "turn on" ?

Thanks for any help
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#1
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10 Reply
Re:TD-W8970 NAT issues
2013-06-03 11:55:08
Hi.
NAT is enabled when using PPPoA WAN interface.
Since your machines can access each other by IP address, in order to use network name to access internal devices, you can double check the settings on your machines rather than TD-W8970.
TD-W8970 does not block the connection between internal devices and Internal devices behind TD-W8970 are still able to ping or access each other.
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#2
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Re:TD-W8970 NAT issues
2013-06-05 01:59:55
I've now looked at this problem in more detail and the problem seems related to how the TD-W8970 deals with mDNS broadcast from avahi. I'm expecting my machine named "media" to be accessible at "media.local" because that is what the avahi server is configured to do. As far as the machine is concerned, media.local exists at the correct IP address, but no other machine can access or even ping media.local.

I recall seeing Bonjour being fixed in a recent firmware update, so mDNS must have previously been a problem area; I'm assuming the avahi broadcast is not being received and so the IP address for media.local is not being inserted into the address table of the TD-W8970.
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#3
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Re:TD-W8970 NAT issues
2013-06-08 17:18:33
Hi, Bruk, can you post your whole network topology?
'I'm expecting my machine named "media" to be accessible at "media.local" because that is what the avahi server is configured to do. As far as the machine is concerned, media.local exists at the correct IP address, but no other machine can access or even ping media.local.'
What are your "machine"? Are they apple products?
If they are not apple products, you can try to access them by "media".
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#4
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Re:TD-W8970 NAT issues
2013-06-10 17:15:08
The connectivity of the network is very simple no other routers or hubs are involved, and I can replicate the problem with this setup:

"Media Machine" <=====Ethernet====> "TD-W8970" <=====Wi-Fi=====> "Android tablet"

The machine in question is a standard ubuntu (12.04) machine, with an avahi server running, hence the .local assumption.

Before installing the TD-W8970, I was able to access all of the web services running on the many ports of the machine at media.local:8080, media.local:8081, etc. from *any* device connected to the network, be it an Apple device, Android device or a Windows machine.

After installing TD-W8970, Samba compatible machines can normally see "media", but for everything else I cannot access "media" at any of the following common local hostname configurations:

media
media.local
media.lan
media.config

It is only accessible at the ip address of 192.168.1.107, which whilst I've made static for consistency, is still an annoyance to have to type in.
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#5
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Re:TD-W8970 NAT issues
2013-06-13 16:53:23
Hi Bruk
Can apple device or windows machine access "media"? Or all the devices are unable to access "media"?
If the windows machine is connected to TD-W8970 via an ethernet cable, can it access "media"?
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#6
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Re:TD-W8970 NAT issues
2013-06-14 17:50:30
As I said, for samba compatible machines whether wired or wireless, the media machine is available at "media", but this is a feature of the samba protocol.

The problem, in short, is that the TD-W8970 is not automatically making local network machines available with a suffix of .lan, .local or .config, which is something every router I've ever owned or used has done out of the box. This makes local machines unreachable by name (samba support is not a valid solution), the fact it is also not receiving and dealing with the avahi broadcast as mentioned in post #3, is an additional annoyance.
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#7
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Re:TD-W8970 NAT issues
2013-06-17 11:27:51
Hi Bruk
Finally, I have done a similar test. The network topology is like the following picture shows:

"ubuntu computer" <=====Wi-Fi====> "TD-W8970" <=====Wi-Fi=====> "PC"

The test result is that the PC can successfully access the ubuntu computer via its hostname with a suffix of .local like the following picture shows:
[ATTACH=CONFIG]598[/ATTACH]

Meanwhile, the PC can also Ping the ubuntu computer via its hostname with a suffix of .local like the following picture shows:
[ATTACH=CONFIG]599[/ATTACH]

I also captured the MDNS data packets in ubuntu computer like the following picture shows, and you can see the MDNS packets are correct.
The PC queries the hostname via MDNS, and the ubuntu computer answers the query via MDNS.
[ATTACH=CONFIG]600[/ATTACH]

So from my point of view, TD-W8970 is completely all right.
I have not tested an android tablet because I don't think android system is compatible with bonjour protocol unless you have installed a safari browser in your android tablet.

You can do the same test as I have described above.
If you have done the exactly same test, and you still can't access the media machine via media.local, then I think there may be something wrong with your product.
You can contact the retailer from whom you bought this product to replace this product with a new one.
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#8
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Re:TD-W8970 NAT issues
2013-06-18 16:16:13
Vincent,

I'm unable to see any of the attachments unfortunately, so I've done another test slightly blind, and had exactly the same results, until I read between the lines of your reply and saw the reliance on Bonjour. The Bonjour service is not installed on any of my machines, but once I installed and started it on a windows machine, I could reach media.local and after stopping the service I could not reach media.local (Test this yourself and I'm sure you'll see the same result). This also explains why no android or bonjour incompatible devices are unable to see the machine.

So yes, as I originally stated, the TD-W8970 does not properly deal with local network machine names, which is something (as I've previously said) that every other router I've owned does out of the box; what it does do is not prevent Bonjour from working.

This *is* a problem and does need fixing, because I'm by no means a minority in not using Apple's zeroconf client side service, and this feature is the only thing lacking in what is otherwise a fine piece of kit.

I know the TD-W8970 uses some variation of OpenWRT as it's software, and as OpenWRT does handle zeroconf properly it shouldn't be too big of a deal to enable for the device.
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#9
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Re:TD-W8970 NAT issues
2013-06-18 17:42:59
Hi Burk

I can't see how your computer without bonjour service can access your ubuntu computer via hostname.
Actually I can't visit ubuntu computer if my windows computer is not running bonjour service.

So please do me a favor, you can help me complete the test below to capture some data packets.
Then maybe I can analyze these data packets to find out what is going on.

"Ubuntu computer" <=====Ethernet====>"windows computer (without bonjour service)"

Your windows computer should be running wireshark software to capture data packets, and then your windows computer can try to access ubuntu computer via hostname.
After your windows computer has successfully visited your ubuntu computer, you can stop capturing data packets and send these packets to me.

My e-mail address is ilookhandsome@126.com.
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#10
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Re:TD-W8970 NAT issues
2013-06-19 00:26:22
Vincent,

It might take a little while to get the specific wireshark logs, but I'm fairly certain the reason I can access my ubuntu machine from a windows machine when bonjour isn't running is because of samba doing roughly what bonjour is doing. It's likely you aren't seeing the same with your ubuntu setup if there are no samba shares and/or the samba daemon isn't running.

So what I'm currently seeing:

Via Samba: Windows accesses the Media machine at "media"
Via Bonjour: Windows accesses the Media machine at "media.local"

You're seeing the same with bonjour, in that when the service is running you have access, when it isn't running you have no access.

This is exactly my point, it shouldn't only be the client machine running bonjour receiving the mDNS broadcast and inserting the name into it's own lookup table, the router should also be doing it. If that were the case, one named machine would be accessible by every other connected machine using that name or name.suffix, which is what I was seeing before using the TD-W8970.
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#11
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