PPPoE host-uniq

stephenw10

Hmm, interesting. Entering an ascii string there converts it to hex and ! should be valid. Looks like there's an input check bug there.
However you can also enter hex values there directly. I tested with 0x74657374, "test".
You can see the generated mpd conf file in /var/etc to check. It just uses the hex value directly so you should be able to enter it that way.

If that still doesn't work you can use an entirely custom mpd .conf file by simply putting it in /conf. Just copy the correctly named file from /var/etc, for example mpd_wan.conf, and edit it directly.
Using that method allows you to do pretty much anything mpd is capable of.

Steve

stephenw10

Actually the input validation is correct for the expected data there. If you need to enter anything other than Letters and Numbers you need to enter it as hex directly.

Steve

trollshiro

@stephenw10

Hi Steve,
thanks, I will give it a try in the WE. It seems my ISP is doing something non-standard so do you have any official documentation about host-uniq? Haven't found much except RFC 2516.

Andrea

stephenw10

I don't think there is anything in the pfSense docs about it dircetly.

The information in the two threads and the redmine feature request is probably all there is.

It's not that complex though. You enter it in the gui as either hex dircetly or as ascii (limited to numbers and letters) and that value is prepended to the pppoe service value in mpd.conf like:

set pppoe service "0x61616161|test"

Resulting in:

Frame 66: 67 bytes on wire (536 bits), 67 bytes captured (536 bits)
Ethernet II, Src: ADIEngin_12:17:7c (00:08:a2:12:17:7c), Dst: silicom_0f:74:48 (90:ec:77:0f:74:48)
PPP-over-Ethernet Discovery
    0001 .... = Version: 1
    .... 0001 = Type: 1
    Code: Active Discovery Offer (PADO) (0x07)
    Session ID: 0x0000
    Payload Length: 47
    PPPoE Tags
        AC-Name: test_box1.stevew.lan
        Service-Name: test
        Host-Uniq: 61616161
        AC-Cookie: c015738801f8ffff

I expect to see something here but there's nothing.

Edit: In fact this is documented here:
https://www.freebsd.org/cgi/man.cgi?query=ng_pppoe#CONTROL%09MESSAGES

Steve

trollshiro

@stephenw10

Hi Steve,
thanks for you reply.

your explanation was enough, thank you, I need the documentation to argue with my ISP, in case.
Anyway I was able to reproduce the string from my ISP but it's still not working, the only difference I can see between my dump and the one from ISP (and yours) is that the TAGS are sent in the reverse order. Service-name should be sent first I guess, could it be the reason why I got a timeout?

set pppoe service "0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa|Test"

Payload Length: 40
PPPoE Tags
    Tag: Host-Uniq (0x0103)
    Tag Length: 28
    Host-Uniq: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa...
    Tag: Service-Name (0x0101)
    Tag Length: 4
    Service-Name: Test

It seems I also found an issue with Tag length, if I add one byte to the host-uniq, two bytes are stripped from service-name. This does not affect me, since service-name is not required by my IPS, it's just to ley you know.

set pppoe service "0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa|Test"

Payload length decrease by 1

Payload Length: 39
PPPoE Tags
    Tag: Host-Uniq (0x0103)
    Tag Length: 29
    Host-Uniq: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa...
    Tag: Service-Name (0x0101)
    Tag Length: 2
    Service-Name: Te

Andrea

stephenw10

Hmm, 32B limit maybe?

I can't imagine the tag order makes any difference. The server replies with a different order here.

trollshiro

@stephenw10

Hi,
I tried OpenWRT that send the packet in the same order of my ISP router, but I still have timeout. The ISP is obviously doing something nasty to prevent use of non-proprietary router, but packets from ISP and oWRT are identical from what I can see, do you have any suggestion?

About the 32B limit, yes, I think it could be that, but Host-Uniq could be of any lenght as far as I can understand. But again, it's not an issue for me, just something weird that I found out.

Thanks again for your patience

Andrea

stephenw10

Spoof the MAC address of the parent interface to match the ISP router?

trollshiro

@stephenw10

Already done, it was the first thing... (sigh)

JKnott

@trollshiro said in PPPoE host-uniq:

My ISP use host-uniq, but if I fill the field in the GUI, wireshark show that values are sent in EBCDIC.

Actually, it's ASCII. aaaa = 61 ASCII and 81 EBCDIC.

BTW, I started my telecom career as a bench tech overhauling Teletype machines and worked with ASCII and Baudot codes daily. I still have the code card somewhere. There was one system I used to work on, for CN Rail, where the computer worked with ASCII, Baudot, EBCDIC and Hollerith codes, depending on which circuit or device it was talking to.

trollshiro

@stephenw10

After some debugging I found that the ISP router sent out PADI packets with a weird timing

11:24:53.046530	XX:XX:XX:XX:XX:XX		Broadcast		PPPoED	58	Active Discovery Initiation (PADI)
11:24:53.707597	XX:XX:XX:XX:XX:XX		Broadcast		PPPoED	58	Active Discovery Initiation (PADI)
11:24:54.707684	XX:XX:XX:XX:XX:XX		Broadcast		PPPoED	58	Active Discovery Initiation (PADI)
11:25:06.707842	XX:XX:XX:XX:XX:XX		Broadcast		PPPoED	58	Active Discovery Initiation (PADI)

And it always start working after the the 4th packet is sent. I cannot see the PADO anyway, probably it's filtered by the ONT.

There is also a sort of counter in the corresponding host-uniq field.

Host-Uniq:XXXXXXXXXXXXaaaaaaaa01000000aaaaaaaa4621426f7820...
Host-Uniq:XXXXXXXXXXXXaaaaaaaa01000000aaaaaaaa4621426f7820...
Host-Uniq:XXXXXXXXXXXXaaaaaaaa01000000aaaaaaaa4621426f7820...
Host-Uniq:XXXXXXXXXXXXaaaaaaaa02000000aaaaaaaa4621426f7820...

So I gave up, it's completely out of standard.
Do you think it's possibile to use the ISP router only for PPPoE authentication and pfsense as an actual router?

stephenw10

Possibly if it has some sort of bridging mode. I would not hold my breath though.

Is that "counter" always the same? Have you tried just using the 4 packet string?

Steve

trollshiro

@stephenw10

It increase by one after 3 packets and then by another one, so it's something like this:

01000000 (0.5 sec)
01000000 (1 sec)
01000000 (12 sec)
02000000 (15 sec) -> here I got connectivity
03000000
03000000
03000000
04000000

So I tried to replicate that with a stupid shell script that called mpd5, sleep xx, kill, and do that again with a different mpd.conf file (with another string) but it lead nowhere (timing is not so accurate).

trollshiro

@stephenw10

Hi,
it's solved now.

After some fights with the IPS they changed some settings and I was able to connect directly from my PC (Windows, no MAC spoofing required) but not yet from PFsense. After some debug I found they accept only PAP and they drop the connection with any other protocol so I changed this line in mpd_wan.conf

set link accept chap pap eap

to

set link accept pap

Now it connects smoothly, thanks a lot for your help Hope this could be useful to someone else.

Note: my provider requires also that VLAN is setted to 835, I guess it has something to do with VPI-VCI

stephenw10

Still need to send the host-uniq value?

Steve

trollshiro

@stephenw10

No, it's not needed anymore. The only difference with a standard config is PAP.