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OneST8
join:2013-08-25
Ajax, ON

OneST8

Member

Advanced Static Routing Question

Hey all,

I'm currently trying to do something rather advanced with my networking, mostly for experiment purposes but also because it'd be rather convenient if it would work the way I'd like. I know it's *possible* in theory, just not sure if this Bell VDSL modem is capable of doing what I need or if I've just tripped up somewhere.

Some basics first: I have the prerequisite static IP assigned via PPPOE and then I've purchased the /30 subnet on top of this to get a second usable IP address.

Let me elaborate the network topology...

Hardware Legend:

BellModem: this is a Bell supplied rental VDSL modem w/wifi and 4-port
LinuxRouter: a machine with 3 network cards (4 actually, but one unused)
LocalNet: 192.168.2.0/24 network (connected to BellModem)
HomeNet: 192.168.0.0/24 network
ServerNet: 10.0.0.0/8 network


BellModem
|
| (192.168.2.0)
|
eth2 -- LinuxRouter
|-- HomeNet via eth0
`-- ServerNet via eth1


What I want to do is route the /30 from the BellModem, over eth2 and over eth1 to a server that has two network interfaces (one configured for 10.0.0.0 and the other configured for the static /30).

I currently have everything working where I can reach the static /30 interface from LocalNet, HomeNet and ServerNet. However, I cannot reach the static/30 from the outside internet.

Traceroute follows from my remote host's IP all the way to the BellModem's external IP but then it's all * * *'s the rest of the way to nothing and obviously ping never replies.

On the BellModem I have a static route that points the /30 subnet to the LinuxRouter's eth2 as the gateway and on the LinuxRouter I have another route specifying that the gateway for the /30 is 10.0.0.1 (eth1). With that, I'm able to traceroute and ping from any of the internal networks perfectly fine but for some unknown-to-me-reason I cannot ping from the external internet. I also can't seem to get verbose logging from the BellModem so I can't even tell how the packets are failing to be routed.

I hope the above made sense and if further details are needed for clarification, please ask!

Any help or insights would be greatly appreciated. Who's up for the challenge?!

-- My best

PS: Bonus if you live in GTA area; I'll buy beer in thanks!

TSI Gabe
Router of Packets
Premium Member
join:2007-01-03
Gatineau, QC

TSI Gabe

Premium Member

I would configure your modem in bridge mode and have your linux router do the PPPoE...it would make your life a hell of lot easier.
Wizza
join:2013-08-23

Wizza to OneST8

Member

to OneST8
So if I understand you correctly, the goal is to connect from the internet to the public IP on the server interface.

1. What I want to do is route the /30 from the BellModem, over eth2 and over eth1 to a server that has two network interfaces (one configured for 10.0.0.0 and the other configured for the static /30).

By Static /30 I am guessing you mean this interface as the second IP address you have obtained and assigned to the server interface? Seems a little over kill for me. One, because you could just give this interface a local 10.0.0.0 address and just double NAT from BellModem to Linux Router to Server. Two, you really want your server to have a public address directly? However, you know your purpose the best. I am being objective. Can you post a ipconfig or ifconfig of this server?

Next, so the eth1 on LinuxRouter has an IP of 10.0.0.1 (as you mentioned below) and is attached to the server on which interface? I would assume some sort of 10.0.0.* IP or else this won't work. Which leaves me to think that the static/30 interface on the server is attached to who? I am missing something here

2. I currently have everything working where I can reach the static /30 interface from LocalNet, HomeNet and ServerNet. However, I cannot reach the static/30 from the outside internet.

How are you reaching it from the local nets? Ping the public IP that is assigned to the Server interface?

3. Traceroute follows from my remote host's IP all the way to the BellModem's external IP but then it's all * * *'s the rest of the way to nothing and obviously ping never replies.

The BellModem forwards the packet to Linux Router but Linux Router doesnt know how to send a reply back to the internet. Can you try to get on the LinuxRouter and ping something on the internet like 4.2.2.2 or something public and see if it gets through?


anon1234
@teksavvy.com

anon1234 to OneST8

Anon

to OneST8
I would guess that NAT is being done by the Bell modem?

My guess is that it can't deal with routing the /30 and "not natting" it... I wouldn't be surprised if in fact the traffic was getting through and crossing eth1, but on the way back out to the Internet, the modem is messing with it.

Like Gabe said, PPPoE on your Linux machine is your best bet...

Cheers...
OneST8
join:2013-08-25
Ajax, ON

OneST8 to TSI Gabe

Member

to TSI Gabe
There isn't any obvious way to set this Bell modem into bridge mode.
OneST8

OneST8

Member

So I've dug deeper into the Bell modem/wifi/router (CellPipe 7130) and I should be able to just use it as a PPPoE modem as long as I de-configure the connection in web admin.

Will try this tonight.

TSI Gabe
Router of Packets
Premium Member
join:2007-01-03
Gatineau, QC

TSI Gabe

Premium Member

You can take a look at this as well.

»Line Stats & Telnet Unlock Tool for Sagemcom 2864 (V2.0.1)
OneST8
join:2013-08-25
Ajax, ON

OneST8

Member

I've got it all running!!! Wooo!!!

There is no button to enable bridge mode for Cellpipe 7130; just plug in the Ethernet and dial in!

All the routing works perfectly the way I need and as a bonus, both of the static/30s are usable!

Elated!

I'm gonna do a nice write up of my network setup and will post the link in a thread here for all you lovely bridge-folk to digest. By far one of my best side projects in a long time.

Cheers!