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darkrabbit
join:2012-12-12

darkrabbit

Member

Bell FTTH PPPoE issue with SagemCom 2864, need to bridge

Hi all,

I just got Bell Business Internet, static IP, and noticed something very odd about PPPoE with the Sagemcom 2864: it drops certain PPPoE frames. This might be affecting more than just me as I've read a number of threads about issues with Sagemcom's.

The Issue:
=======

I am using a Palo Alto PA500 firewall in Bell's laughable 'bridge mode' *ahem* PPPoE forwarding, and what happens, as evidenced by a ton of Wireshark pcaps, is that the PADI frame (PPPoE discovery) gets sent from the PA500 to the modem then to the ONT. The PADO frame (PPPoE offer) comes back from the ONT but is then dropped by the modem so it never reaches the PA500. This doesn't happen on my OSX or Win7 boxes when testing the PPPoE connection and the only reason I am seeing is:

- With the PA500, it sends an EoL PPPoE tag in the frame (in the PADI). The ONT then replies properly (PADO) but does not send a Reply-Session-ID tag. The modem drops the PADO. (Note that a EoL tag is RFC compliant, so there's nothing the PA is doing wrong).

- With the Win7 and OSX boxes, the EoL tag isn't sent in the PADI. The ONT replies with a Reply-Session-ID tag in the PADO and the modem passes the PADO along.

I tried tons of packet replays and captures, and this appears to be the issue. The Sagemcom's PPPoE forwarding is doing some checks and drops it shouldn't in a true bridge mode.

That's the short story. The long one is much... longer.

Of course Bell was of no help, but not much they can do about faulty equipment.

What I need:
========

SO....

I have scoured DSLReports for hours looking for the complete story of putting the Sagemcom into true bridge mode with FTTH. This thread:

»[DSL] Sagemcom F@ST 2864 bridge mode guide

Says it's for VDSL only, and for FTTH go here:

»Re: [DSL] bridge mode on Sagemcom f@st2864.

However this seems to be an incomplete description and seems to be replying to two questions, only one of which is answered (and I can't tell which). It says this bypasses the VLAN tag but I don't think that's what you want to do? The VLAN tagging is necessary as everything is passed on VLAN 35...

So if someone has successfully gotten the Sagemcom into true bridge mode on an FTTH connection can you let me know what you followed / did? I don't have IPTV or Fibe TV or whatever on this, it's Internet only.

I should also point out, I have followed the directions to downgrade the firmware and enable telnet. I can't find the link but it's here somewhere

Alternatively, I don't care about the Sagemcom so if I can replace it with something else I am happy to. I only care about the PA500 doing PPPoE initiation. If I can put an Asus box in place of the modem and have it tag VLAN 35 and drop into true bridge mode, all the better.

Any help is appreciated, thanks in advance!

-J

JAMESMTL
Premium Member
join:2014-09-02

JAMESMTL

Premium Member

As you have FTTB you really have no need for the sagecom unless you also have iptv.

Just connect your router directly to the ONT, enable vlan 35 tagging and pppoe from the router. If your router doesn't support vlan tagging you could also put a cheap smart switch between the ONT and router and have the switch to the tagging.
darkrabbit
join:2012-12-12

darkrabbit

Member

Really... is that all that's required? I imagine I can set up my Dell 6248 to tag 35.

Anyway, it's a weird issue which would be resolved nicely by making the Sagemcom a doorstop. I'll try it.

Thanks

-J

JC_
Premium Member
join:2010-10-19
Nepean, ON

JC_

Premium Member

said by darkrabbit:

Really... is that all that's required? I imagine I can set up my Dell 6248 to tag 35.

Yes, that's all you need to do. Just tag and go