ATT Uverse RG Bypass (0.2 BTC)

rajl

ng_one2many is what I was referring to. The man page states that it has several transmission modes, including round-robin and transmit-all. The man page says that the round robin mode is the default, but my experience when playing with it is that transmit-all was the default. In either case, you could easily set the transmission mode to transmit-all to ensure that you get the desired behavior. So it will work and is simpler to work with than ng_tee.

That's great research on the ng_ether issue. It's been holding me up for awhile, forcing me to do my testing on other distributions (e.g., vanilla FreeBSD and OPNSense) and then curse when I couldn't get it working on PFSense. I'll have to see if it works with my scripts on a VM or PFSense. It should, but Murphy's law always strikes me down!

aus

Doh! Good catch on the ng_one2many transmit-all algorithm. I was looking at an old man page from an earlier version of FreeBSD, which it didnt support transmit-all yet. That's what I get for googling the man pages, instead of reading them in terminal! May give this a shot later… I'll report back if I have any success.

Cheers!

aus

It worked!! True U-verse bridge mode on pfSense!


[2.4.2-RELEASE][root@pfsense.knox.lan]/root: ngctl list
There are 9 total nodes:
  Name: T               Type: tee             ID: 00000021   Num hooks: 3
  Name: ue0             Type: ether           ID: 00000003   Num hooks: 2
  Name: vlan0           Type: vlan            ID: 00000024   Num hooks: 2
  Name: <unnamed>Type: socket          ID: 00000006   Num hooks: 0
  Name: ngctl96372      Type: socket          ID: 00000047   Num hooks: 0
  Name: ngeth0          Type: eiface          ID: 00000027   Num hooks: 1
  Name: waneapfilter    Type: etf             ID: 0000002a   Num hooks: 3
  Name: laneapfilter    Type: etf             ID: 00000031   Num hooks: 3
  Name: em0             Type: ether           ID: 00000019   Num hooks: 2
[2.4.2-RELEASE][root@pfsense.knox.lan]/root: ifconfig em0
em0: flags=8843 <up,broadcast,running,simplex,multicast>metric 0 mtu 1500
	options=40098 <vlan_mtu,vlan_hwtagging,vlan_hwcsum,vlan_hwtso>ether xx:xx:xx:xx:xx:xx
	hwaddr xx:xx:xx:xx:xx:xx
	media: Ethernet autoselect (1000baseT <full-duplex>)
	status: active
[2.4.2-RELEASE][root@pfsense.knox.lan]/root: ifconfig ue0
ue0: flags=8843 <up,broadcast,running,simplex,multicast>metric 0 mtu 1500
	options=8000b <rxcsum,txcsum,vlan_mtu,linkstate>ether xx:xx:xx:xx:xx:xx
	hwaddr xx:xx:xx:xx:xx:xx
	media: Ethernet autoselect (100baseTX <full-duplex>)
	status: active
[2.4.2-RELEASE][root@pfsense.knox.lan]/root: ifconfig ngeth0
ngeth0: flags=8a43 <up,broadcast,running,allmulti,simplex,multicast>metric 0 mtu 1500
	options=28 <vlan_mtu,jumbo_mtu>ether xx:xx:xx:xx:xx:xx
	inet xx.xx.xx.xx netmask 0xfffffc00 broadcast xx.xx.xx.xx
	media: Ethernet autoselect (1000baseT <full-duplex>)
	status: active</full-duplex></vlan_mtu,jumbo_mtu></up,broadcast,running,allmulti,simplex,multicast></full-duplex></rxcsum,txcsum,vlan_mtu,linkstate></up,broadcast,running,simplex,multicast></full-duplex></vlan_mtu,vlan_hwtagging,vlan_hwcsum,vlan_hwtso></up,broadcast,running,simplex,multicast></unnamed>

For reference…

em0 is connected to my ONT.
em1 is connected to my LAN
ue0 is connected to my RG (via USB ethernet)
ngeth0 is the VLANed device which is configured as my WAN in pfSense

Commands to get it running (thanks for the help on ng_tee rajl!) ...


# copy and load ng_etf kernel module

kldload /boot/kernel/ng_etf.ko

#
# setup netgraph nodes
#

# list out netgraph nodes

ngctl list

# pfSense for some reason detaches ether devices. reattach any missing devices.

php -r 'pfSense_ngctl_attach(".", "em0");'

# create tee node to split em0 traffic (one for EAP, one for VLAN0)
ngctl mkpeer em0: tee lower left # may get a warning
ngctl name em0:lower T

# create vlan node + eiface
ngctl mkpeer T: vlan right downstream
ngctl name T:right vlan0
ngctl mkpeer vlan0: eiface vlan0 ether
ngctl msg vlan0: 'addfilter { vlan=0 hook="vlan0" }'

# create etf and connect to em0 (ONT)
ngctl mkpeer T: etf left2right downstream
ngctl name T:left2right waneapfilter
ngctl connect waneapfilter: em0: nomatch upper

# create etf and connect to em1 (RG) 
ngctl mkpeer ue0: etf lower downstream
ngctl name ue0:lower laneapfilter
ngctl connect laneapfilter: ue0: nomatch upper

# define filters for EAP traffic
ngctl msg waneapfilter: 'setfilter { matchhook="eapout" ethertype=0x888e }'
ngctl msg laneapfilter: 'setfilter { matchhook="eapout" ethertype=0x888e }'

# use filters to bridge EAP traffic
ngctl connect waneapfilter: laneapfilter: eapout eapout

# change MAC address to match RG (also can be done in pfSense)
ifconfig ngeth0 ether xx:xx:xx:xx:xx:xx

There is still worked to be done though to make this perfect though…

1. Explore using ng_one2many to see if that simplifies the netgraph a bit
2. Automate / Harden change so its persistant across reboots (rajl already documented this earlier)
3. Document!

And for what it's worth, I'm running this pfSense in a virtual machine via Proxmox (QEMU/KVM). I couldnt get the VLAN0 traffic to bridge across the interface into pfSense, so I ended up doing a PCI passthrough of the NIC device.

rajl

That's awesome!!! My suspicion is that this would run on baremetal just fine (have to test though). So let's say there's a 4th todo - test this to run on baremetal for those of use that don't virtualize! :-) Hopefully, it won't take too much modification.

This should be pretty easy to automate so that it executes across reboots. Just save your commands as a shell script (don't forget the #!/bin/sh at the beginning of the file) and follow the PFSense instructions for executing shell scripts at the end of the boot process.

https://doc.pfsense.org/index.php/Executing_commands_at_boot_time

I read somewhere that ATT will occassionally push firmware updates to the RG, which this setup may have problems with because the RG is being isolated from the ATT network. But that's a bridge to cross when we get there.

Tantamount

Would it be possible to have ONT go to port A of a switch set to vlan 20
and have port B of that switch also on vlan 20 connect to the RG's ONT port?

Would a switch normally process/filter those 802.1x packets in such a setup?

My pfsense vm is in a different area of the house on a different switch and I'm curious if I'll be able to get this working.

Also, is there any practical benefit to doing this? For instance, would it open outgoing tcp port 25 traffic?

aus

@Tantamount:

Would it be possible to have ONT go to port A of a switch set to vlan 20
and have port B of that switch also on vlan 20 connect to the RG's ONT port?

Would a switch normally process/filter those 802.1x packets in such a setup?

My pfsense vm is in a different area of the house on a different switch and I'm curious if I'll be able to get this working.

Also, is there any practical benefit to doing this? For instance, would it open outgoing tcp port 25 traffic?

I don't know the answer to your question, but I suspect that won't work. The problem is that ONT traffic comes in on VLAN0 and needs to egress on VLAN0. I'm not sure your switch would tag VLAN0 <-> VLAN20 accordingly.

Also, I'm having some duplicate packets in my previous setup. Hoping one2many might solve that. More to come…

rajl

@Tantamount:

Would it be possible to have ONT go to port A of a switch set to vlan 20
and have port B of that switch also on vlan 20 connect to the RG's ONT port?

Would a switch normally process/filter those 802.1x packets in such a setup?

My pfsense vm is in a different area of the house on a different switch and I'm curious if I'll be able to get this working.

Also, is there any practical benefit to doing this? For instance, would it open outgoing tcp port 25 traffic?

I'll try to answer your questions in detail.

First, the switch setup you're describing won't work because your switch would block the traffic for several reasons. First, if the switch would drop the ethernet frames because ATT tags them as vlan0, but you're setting your ports for vlan20. Second, your switch would probably drop all the authentication frames (802.1X) because most (but not all) switches are fully compliant with 802.1D, which requires that switches and bridges not forward 802.1X frames. However, some switches are not standard compliant and will forward the frames anyway.

That said, you could always run a long cable from one of the house to the other to solve the problem.

Regarding your question about practical benefits, the main practical benefit is performance. The RGs tend to have (1) a small state table with a limited number of entries and (2) middling (at best) performance ARM processors that start to choke under load when you start to do "real routing." As an example, get a few good bit-torrents going on a 1-Gig connection and they try to browser the web. Your performance will crawl because the RG's state table is too small to keep track of all of the connections and the RG's processor is unable to process all the connections at line-speed. Bypassing the RG to use your own PFSense box solves both of these problems.

Some older (but still relevant) articles on why you would want to replace consumer grade routers with an x86 router (such as one using PFSense) are below:

https://arstechnica.com/gadgets/2016/01/numbers-dont-lie-its-time-to-build-your-own-router/
https://arstechnica.com/gadgets/2016/09/the-router-rumble-ars-diy-build-faces-better-tests-tougher-competition/

Tantamount

I was afraid you were going to say that – I tried it last night and was unsuccessful.

I've got one of those Netgate gs-2440's that I'll use instead of the vm. I'll be able to put it right next to the RG and ONT.

pyrodex

Going to try this today with my 4 port SuperMicro physical and report back. Had to install FreeBSD 11.1 in a VM to get the kernel module since the link seems to be dead.

UPDATE:

No luck.

I use the crappy switch trick today and swap VLANs and my igb0 is the MAC of the RG. My igb0 (WAN) is connected into my bypass switch on a VLAN with the ONT and the RG is on another VLAN that gets flipped and flopped if the internet goes down.

I tried the script and connected igb0 straight into the ONT and igb3 to the RG removing my bypass switch out of line. I had no luck and the RG would attempt to AUTH the port on the ONT but never went past that.

Here is the script I used:


#igb2 is connected to the ONT
#lagg0 is connected to the LAN
#igb3 is connected to the RG
#ngeth0 is the VLANed device which is configured as my WAN in pfSense
# copy and load ng_etf kernel module

/sbin/kldload /boot/kernel/ng_etf.ko

#
# setup netgraph nodes
#

# list out netgraph nodes

/usr/sbin/ngctl list

# pfSense for some reason detaches ether devices. reattach any missing devices.

php -r 'pfSense_ngctl_attach(".", "igb0");'

# create tee node to split ONT traffic (one for EAP, one for VLAN0)
/usr/sbin/ngctl mkpeer igb0: tee lower left # may get a warning
/usr/sbin/ngctl name igb0:lower T

# create vlan node + eiface
/usr/sbin/ngctl mkpeer T: vlan right downstream
/usr/sbin/ngctl name T:right vlan0
/usr/sbin/ngctl mkpeer vlan0: eiface vlan0 ether
/usr/sbin/ngctl msg vlan0: 'addfilter { vlan=0 hook="vlan0" }'

# create etf and connect to ONT
/usr/sbin/ngctl mkpeer T: etf left2right downstream
/usr/sbin/ngctl name T:left2right waneapfilter
/usr/sbin/ngctl connect waneapfilter: igb0: nomatch upper

# create etf and connect to RG
/usr/sbin/ngctl mkpeer igb3: etf lower downstream
/usr/sbin/ngctl name igb3:lower laneapfilter
/usr/sbin/ngctl connect laneapfilter: igb3: nomatch upper

# define filters for EAP traffic
/usr/sbin/ngctl msg waneapfilter: 'setfilter { matchhook="eapout" ethertype=0x888e }'
/usr/sbin/ngctl msg laneapfilter: 'setfilter { matchhook="eapout" ethertype=0x888e }'

# use filters to bridge EAP traffic
/usr/sbin/ngctl connect waneapfilter: laneapfilter: eapout eapout

# change MAC address to match RG (also can be done in pfSense)
ifconfig ngeth0 ether <mac></mac>

aus

It's hard to say what your exact issue is without more information.

However, the first thing I would do is run some tcpdumps to see what's going on.

You should run tcpdumps on the ONT interface and the RG interface:

tcpdump -ei em0
tcpdump -ei em1

From the RG interface, you should see some EAPOL starts:

MAC (oui Unknown) > MAC (oui Unknown), ethertype EAPOL (0x888e), length 60: EAPOL start (1) v2, len 0

These packets come every so often. I think the RG does some backoff /delay if it doesnt immediately auth correctly. You can always reboot your RG to initiate.

If your netgraph is setup correctly, this EAP start packet from the RG will be bridged onto your ONT interface. Then you should see some more EAP packets from the ONT interface and RG interface as they negotiate 802.1/X EAP authentication.

Once that completes, you should start seeing 802.1Q (tagged as vlan0) traffic on your ONT interface.

I start another tcpdump on my VLAN0 netgraph device to see if netgraph is bridging over the VLAN0 to ngeth0:

tcpdump -ei ngeth0

If I dont see traffic being bridged between ngeth0 and the ONT interface, then netgraph is not setup correctly. At this point, ngeth0 needs to DHCP using the authorized MAC address. You should see an untagged DCHP request on ngeth0 carry over to the ONT interface tagged as VLAN0. Then you should get a DHCP response and you're in business.

Tantamount

Hey guys,

I'm trying to wrap my head around all of this and how it works.

I believe the network diagram I've created is how things should be wired up.

igb0 (WAN/ONT) needs to have the mac address of the ATT Residential Gateway (RG).
igb2 is connected to the RG and somehow the ONT<->RG authentication magic happens (EAP Proxy?).
igb1 (LAN) goes to switch.

Somehow pfsense is not confused by the mac address on igb0 and the mac address of the RG connected to igb2 being the same.

Are ethernet aliases used? (I think pfsense calls them virtual ips?) I.E. igb0 has an alias for vlan0 traffic which I think is just the ONT<->RG traffic, while the regular igb0 has DHCP (or static) internet address assigned?

network-diagram1.jpg_thumb

Tantamount

From what I've read from the original DSL Reports thread (http://www.dslreports.com/forum/r29903721-AT-T-Residential-Gateway-Bypass-True-bridge-mode)
There are two possible solutions to get the ONT to talk to the RG through something.
One is to set up a bridge between the two interfaces (igb0 and igb2). However, 801.D compliance means that 801.x packets won't pass across, and pfsense's drivers are compliant. One would need to custom compile the drivers to break this compliance.
Two is to use a proxy. However, it seems that the proxy solutions mentioned are incompatible?
I found two proxy solutions. One is written in python:
https://github.com/jaysoffian/eap_proxy
However, Pyrodex mentioned in this thread that it has a linux dependency (PFRING).
As was mentioned by variance in this thread, the other needs to be compiled –
https://github.com/kuwerty/eapolproxy
However, from the DSL thread:

I checked out the eapolproxy, and successfully compiled it on my freebsd dev box. After getting some dependencies (libstdc++) onto pfsense, it does start and appears to be passing the EAP traffic from the RG on OPT1 up to the WAN interface where the ONT is, but nothing ever comes back - it just keeps spamming the EAPOL start and logoffs. I will have to keep playing with it, but I feel like the solution is close. It would be good to have some others try this…

Indeed, that person created an issue in github about this, but it looks like the code has been long abandoned.

Rajl then came up with the netgraph solution which, apparently, should be able to bridge the two interfaces in such a way that the 801.x traffic passes across. However pfsense's oddities breaks this a bit.

aus got this working, but must rely on the linux vm host to do part of the work – something the rest of us cannot rely on.

Pyrodex is testing on bare metal. Since pfsense doesn't come with the ng_etf.ko file, he pulled it from a fresh copy of reebsd 11.1.

Tantamount

@pyrodex:

/sbin/kldload /boot/kernel/ng_etf.ko

Pyrodex,

In your script, does this have to execute in addition to loading the module at boot? For security reasons, I thought kernel modules could only load at boot in pfsense?

pyrodex

I was able to see the interfaces in the ngctl list command so I know it loaded and they got inserted. I haven't had a chance to do TCPdumps yet and will try again this Sunday while the wife is at work.


kldstat
Id Refs Address            Size     Name
 1   24 0xffffffff80200000 2c2da38  kernel
 2    1 0xffffffff82e2f000 316ae8   zfs.ko
 3    2 0xffffffff83146000 cae8     opensolaris.ko
 4    1 0xffffffff83221000 32ce     cpuctl.ko
 5    1 0xffffffff83225000 8191     aesni.ko
 6    1 0xffffffff8322e000 4700     cryptodev.ko
 7    1 0xffffffff83233000 2c63     coretemp.ko
 8    1 0xffffffff83236000 191f     ng_etf.ko

rajl

Tantamount,

Your network diagram is correct and you're definitely heading in the right direction as far as "wrapping your head around this" goes.

If you're remotely familiar with the OSI networking model this makes a lot more sense. Basically, we are creating a script using Netgraph to do layer 2 (Ethernet Frame) processing to relay authentication frames between the ONT and the RG while diverting all other Ethernet Frames from the ONT up to layers 3-7 of the PFSense network stack.

To go into more detail, ATT's RG uses embedded certificates and the EAPOL protocol to authenticate the RG with the ONT and ATT's wider network. However, the EAPOL is susceptible to what's known as a "man-in-the-middle" attack where a third-party can intercept the traffic. What we are (attempting) to do is two things:
(1) Relay all EAPOL ethernet frames between the RG and the ONT. This requires using MAC address spoofing so that the WAN interface on the PFSense router uses the MAC address of the RG instead of its own MAC address. This makes the ONT think it is communicating with the RG instead of an unauthorized PFSense device. Virtual IPs are not used (they are something completely different as they are operating at layers 3-7 of the network stack).
(2) Intercept all other ethernet frames and send them up to layers 3-7 of the PFSense network stack for further firewall processing.

Step 1 can be solved two ways:
(1) Bridge the traffic. This requires a non-standards compliant bridge device or driver (a trivial modification to the FreeBSD bridge kernel module if you know C programming).
(2) Write a program that intercepts and relays the EAPOL frames (i.e., performs a man-in-the-middle attack). The problem with the EAP_Proxy script is that it relies on a number of Python libraries that provide linux specific operating system calls. However, the algorithm that it uses is really simple, so I created a short NetGraph script to duplicate the functionality of the eap_proxy script because Netgraph is part of the FreeBSD base.

The final issue that is causing problems on bare-metal is that ATT is tagging all internet traffic as being assigned to VLAN 0. Technically, VLAN 0 means the frame is not assigned to a VLAN. However, ATT uses it as an actual VLAN identifier. FreeBSD, being overly standards compliant, therefore refuses to create a virtual interface on VLAN 0 and bind services to VLAN 0, allowing for traffic to be read from and written to VLAN 0. Solve that problem, and this will work on bare-metal. AUS has already solved it by using PCI pass-through to work around the issue for virtualized PFSense (which will help a lot of people).

Tantamount

@rajl:

The final issue that is causing problems on bare-metal is that ATT is tagging all internet traffic as being assigned to VLAN 0. Technically, VLAN 0 means the frame is not assigned to a VLAN. However, ATT uses it as an actual VLAN identifier. FreeBSD, being overly standards compliant, therefore refuses to create a virtual interface on VLAN 0 and bind services to VLAN 0, allowing for traffic to be read from and written to VLAN 0. Solve that problem, and this will work on bare-metal. AUS has already solved it by using PCI pass-through to work around the issue for virtualized PFSense (which will help a lot of people).

Thanks Rajl.

I thought PCI pass-through makes virtual environments more "bare metal" because it makes the hardware exclusive to one virtual machine. I'm not clear how this would solve the VLAN 0 tagging issue unless his virtual environment was the cause of the problem?

GPz1100

Any more progress on this?

I'm testing using a spare machine while the 4 port nic arrives.

For the moment pfsense is installed baremetal. Running into issues at the following


# create etf and connect to em1 (RG) 
ngctl mkpeer ue0: etf lower downstream
ngctl name ue0:lower laneapfilter
ngctl connect laneapfilter: ue0: nomatch upper

All the previous command execute correctly. Interface names have been adjusted as needed based on how my system identified them.


em0 - intel pro 1000 (builtin) - ONT (WAN)
xl0 - 3com - gateway
ue0 - usb - LAN

So the original snippet is changed to


# create etf and connect to em1 (RG) 
ngctl mkpeer xl0: etf lower downstream
ngctl name xl0:lower laneapfilter
ngctl connect laneapfilter: xl0: nomatch upper

I end up getting this error (including entire input/output to this point).

[2.4.3-RELEASE][root@pfSense.localdomain]/root: kldload /boot/kernel/ng_etf.ko
[2.4.3-RELEASE][root@pfSense.localdomain]/root: ngctl list
There are 2 total nodes:
Name: ngctl57043 Type: socket ID: 00000012 Num hooks: 0
Name: <unnamed>Type: socket ID: 00000006 Num hooks: 0
[2.4.3-RELEASE][root@pfSense.localdomain]/root: php -r 'pfSense_ngctl_attach(".", "em0");'
[2.4.3-RELEASE][root@pfSense.localdomain]/root: ngctl mkpeer em0: tee lower left
[2.4.3-RELEASE][root@pfSense.localdomain]/root: ngctl name em0:lower T
[2.4.3-RELEASE][root@pfSense.localdomain]/root: ngctl mkpeer T: vlan right downstream
[2.4.3-RELEASE][root@pfSense.localdomain]/root: ngctl name T:right vlan0
[2.4.3-RELEASE][root@pfSense.localdomain]/root: ngctl mkpeer vlan0: eiface vlan0 ether
[2.4.3-RELEASE][root@pfSense.localdomain]/root: ngctl msg vlan0: 'addfilter { vlan=0 hook="vlan0" }'
[2.4.3-RELEASE][root@pfSense.localdomain]/root: ngctl mkpeer T: etf left2right downstream
[2.4.3-RELEASE][root@pfSense.localdomain]/root: ngctl name T:left2right waneapfilter
[2.4.3-RELEASE][root@pfSense.localdomain]/root: ngctl connect waneapfilter: em0: nomatch upper
[2.4.3-RELEASE][root@pfSense.localdomain]/root: ngctl mkpeer xl0: etf lower downstream
ngctl: send msg: No such file or directory
[2.4.3-RELEASE][root@pfSense.localdomain]/root:</unnamed>

Not sure how to move forward from this.

Also, I'm a bit confused on how a pci-passthrough (when virtualized) is any different than bare metal, as far as vlan0 tagging is concerned. When the nic is defined as pci-pass through, does the underlying vm have direct access to the nic? This would be similar as a baremetal implementation, no?

Thanks!

jeli

hi I've just been reading this thread.
I have a pfsense router but unfortunately Uverse is not here in Australia, so I can't help practically..

however i see you have got my ng-etf pair set up so I see we have somehow communicated before :-)

let me see if I understand the full picture..

You need to link the ONT (whatever that stands for .. Optical Network translator?) via vlan0 to the RG, but you only want protocol 8xxx to go to the RG, and all other protocols/ethertypes to go to the pfsense IP stack.. is that right?

jeli

this MAY work but may not.. it depends if the packets coming out of the interface have already been stripped of vlan tags.

ONT]–--[em0]lower–-downstream[eapfilter:]nomatch–--vlan0[VLAN]downstream–--upper[em0…
eapout
|
|
|
RG]–----[em1]lower–--------------/

ngctl mkpeer igb0: etf lower downstream
ngctl name igb0:lower eapfilter
ngctl mkpeer igb0: vlan upper downstream
ngctl name igb0:upper vlanheader
ngctl msg vlanheader: addfilter '{ vlan=0 hook="vlan0" }'
ngctl connect vlanheader: eapfilter: vlan0 nomatch
ngctl connect eapfilter: igb1: eapout lower
ngctl msg waneapfilter: 'setfilter { matchhook="eapout" ethertype=0x888e }'

if they haven't then we may need to put the vlan nodes (two) on the other side of the etf node, so that it doesn't see the vlan tags.

Maybe I should add an option to make etf nodes take vlan tags into account.

If you can attach the nghook program to an inserted ngtee node (inserted somewhere in your current graph) and see what comes out. (with -a ).

then we can see what the packets look like.

rajl

@jeli:

hi I've just been reading this thread.
I have a pfsense router but unfortunately Uverse is not here in Australia, so I can't help practically..

however i see you have got my ng-etf pair set up so I see we have somehow communicated before :-)

let me see if I understand the full picture..

You need to link the ONT (whatever that stands for .. Optical Network translator?) via vlan0 to the RG, but you only want protocol 8xxx to go to the RG, and all other protocols/ethertypes to go to the pfsense IP stack.. is that right?

You've actually been talking to me on the FreeBSD mailing lists, but I posted the final results to share with the world and a number of people have been running with it. :)

To help you with the terminology and define the problem:

ONT = Optical Network Terminal. It's the box in your house where the fiber-optic cable is terminated and the signal is converted into an electrical signal. It has an RJ-45 1000BaseT jack that you use to plug the RG into.

RG = Residential Gateway. It's one of those all-in-one wireless routers that is provided by the ISP (AT&T). It's low-end consumer gear that has a number of issues. Many of us have outgrown it's limitations and want to get rid of it. However, we can't because the RG is required for authentication with the ISP.

EAP-OL = Encapsulated Authentication Protocol Over LAN. It works at layer 2 and can be easily man-in-the-middled. The RG uses this protocol to authenticate with the ISP. My suspicion is that the RG is using EAP-OL to authenticate with the ONT so that the ONT can ensure that only an approved, authenticated device is connected to it/the network. However, where the actual end-point for the EAP-OL frames is located is immaterial.