[Problem] How to access a modem connected to LAN1

[lorbet]

Hi all,
I'm using a 7490 for VoIP and a few other things, but I get connectivity through a modem connected to the first lan port.
There's a small hitch in this: the webpage of the same modem is not accessible and I would like to be able to see connection statistics and whatelse.

I saw a few other threads about this problem, like this, this, this, this and this, which makes me think it's not a rare need. One of those threads suggests creating an IPoE connection to access the upstream modem (static routes don't work on the WAN port, apparently), but I need a connection for the VoIP: can I do both with fw 7.29?

Thanks.

P.S: Answers in German welcome.

 

[B612]

Why you don't take the modem inside the 7490?
Who is the ISP?

 

[sonyKatze]

the webpage of the same modem is not accessible

Which IP address does it have?

 

[lorbet]

Why you don't take the modem inside the 7490?

Because it's not a DSL connection, but a FTTH one. Or better, it will be when I'm finished testing the setup.

Who is the ISP?

TIM

 

[frank_m24]

So if you have read the other threads, then you know, that there is no good solution for this.

If the Fritzbox is using PPPOE for the connection, there is no IP on the WAN Port for accessing the modem. Using a second Ethernet cable between Fritz and Modem may cause problems like this:

Wenn der Nachbar heimlich mitsurft

Durch einen Konfigurationsfehler kann ein DSL-Provider die Anschlüsse mehrere Kunden so zusammenschalten, dass sie sich gegenseitig auf die Festplatten schauen können.

www.heise.de

So in principle there are two possibilities:

1. The modem has to become a router in order to provide an IP instead of a PPPOE connection. Then you can access the Web frontend. But it will cause a Double-NAT configuration or router cascade, which may cause additional problems.
2. You have a dedicated connection to the modem, maybe via Wifi.

 

[lorbet]

Which IP address does it have?

192.168.1.1. If I change it to 192.168.178.x and connect it to port 3 or 4, everything works, but then I can't use it.

 

[B612]

But it will cause a Double-NAT configuration or router cascade, which may cause additional problems.

Or he take the 7490 then in IP-Client modus.

 

[sonyKatze]

192.168.1.1

Does it offer a link-local address as well?

FTTH

Who creates the Internet connection? In other words: PPPoE or DHCP, what is used, and which box does it?

 

[lorbet]

Does it offer a link-local address as well?

Not that I know, but it could. I'm currently looking for the manual.
Would it do any good?

Who creates the Internet connection? In other words: PPPoE or DHCP, what is used, and which box does it?

The Fritz Box and another router behind it. Two PPPoE connections.
I don't know exactly what the ONT (which I called modem until now) exactly does, but I know it's more than media conversion.

 

[B612]

What is the exact name of the ONT?

 

[lorbet]

What is the exact name of the ONT?

The models my ISP installs are: ZTE ZXHN F601 and Huawei HG8010H. I still don't have either at hand.

EDIT: However I've also been told there isn't much to look at in there, so perhaps it's really not worth the trouble.

 

[sonyKatze]

Two PPPoE connections

That means, the FRITZ!Box does PPPoE on its WAN port, and that other device is connect (only) to the WAN port. Then, I have no idea. Do other Internet routers from other manufacturers in Italy support that scenario? Perhaps we can learn from those.

 

[lorbet]

Vollzitat gemäß Boardregeln entfernt by stoney

To my knowledge, all FTTH ISPs either provide (read sell) their own router with optical port or, to respect EU directive 2015/2120, provide the customer with an ONT like the devices I mentioned above to which one can connect routers of their own.

The alternatives to this state of things are:

• getting a media converter with a SFP port and hope the technician will have a suitable mini-ONT the day he will come
• getting an ONT of your own making sure it will be compatible with the gear at the other end and making sure to put the serial # of the original one in it so that authentication can work (unsupported option)
• getting something like the Fritz 5530 and tinkering with the supplied GPON SFP module to properly authenticate on the network (unsupported and so far not functioning, but someone is working on it)

There's also a secondary FTTH network (OpenFiber) that some ISPs use. It has a different architecture, but I believe it's also GPON and it relies on external ONTs. In any case, it doesn't reach my home.

 

[sonyKatze]

I meant, are you really using a ‘PPPoE’ connection? In that case, the FRITZ!Box does not talk IP but PPPoE on it WAN port. And therefore, you cannot reach anything IP based via that port. I ask, because with fibre I would not expect PPPoE.

The other question was: How is it designed to reach/access the Web interface of that other box normally:

(a) By changing the wiring or​

(b) do other routers in Italy exist, which support your idea to still the Web interface?​

 

[lorbet]

I meant, are you really using a ‘PPPoE’ connection? In that case, the FRITZ!Box does not talk IP but PPPoE on it WAN port. And therefore, you cannot reach anything IP based via that port. I ask, because with fibre I would not expect PPPoE.

Yes, all residential ISPs here use PPPoE, a solution that's less efficient at network level, but which I'm told simplifies things for user accounting and address allocation.

I used to be able to reach the modem with my debian router, which is now connected to the fritz box and relies on it for PPPoE forwarding. The same physical interface was used at L2 and L3 levels and of course two sets of firewall rules were required, but it worked. Presumably it's an edge case that's simply not taken into account by AVM.

The other question was: How is it designed to reach/access the Web interface of that other box normally:
(a) By changing the wiring or

Apparently. But being an undocumented feature, I suppose it's not even something contemplated officially. The ONT is remotely controlled by the ISP.

(b) do other routers in Italy exist, which support your idea to still the Web interface?

Perhaps the ones with integrated optical interfaces. I suspect the crux of the problem is that using one's own router is something ISPs support reluctantly and only because there's a law mandating so. On a personal note, I was not willing to pay €240 for a custom device and being locked into a contract for an extra 2 years.