adsl/pppoe no longer connecting on 5.1

On my previous FreeBSD version (5.0 April 21 snapshot), my ADSL/pppoe
setup worked fine... as it always has all the way back to 4.x. Now
having installed 5.1-RELEASE, with no other changes, ppp no longer can
seeming no longer connect to my adsl modem. I've been struggling with
this for days.

Is anyone else experiencing this, or can anyone suggest any things to
try? Again I say, my simple config has always worked for me, and i
can't find any reason to suggest it shouldn't any longer.

The modem is an OvisLink (I forget the model at the moment). It has
built in routing/nat capabilities, but I never have used them in the
past (preferring the control/flexibilty of doing it on on the gateway
FreeBSD box). With the problems i've been having however, I've had to
set up the modem to handle the PPPoE itself... it is still plugged
into the same interface on the FreeBSD box, and when the default route
is fixed up the FreeBSD box is on the net: so the modem seems to be
functioning properly, and the cables and interfaces all communicate
without problems.

The stumbling block seems to be that FreeBSD's ppp can no longer
detect carrier on the modem, and so fails. I have tried using "set cd
off" and "dedicated" mode for ppp, but this just then fails at the
next phase since it still can't seem to communicate with the modem.

What i see in my ppp.log (lots of logging):

Jun 11 07:36:58 bee ppp[9076]: Phase: Using interface: tun0
Jun 11 07:36:58 bee ppp[9076]: Phase: deflink: Created in closed state
Jun 11 07:36:58 bee ppp[9076]: tun0: Command: default: ident user-ppp VERSION (built COMPILATIONDATE)
Jun 11 07:36:58 bee ppp[9076]: tun0: Phase: PPP Started (interactive mode).
Jun 11 07:37:00 bee ppp[9076]: tun0: Command: /dev/ttypb: dial dsl
Jun 11 07:37:00 bee ppp[9076]: tun0: Command: dsl: set log Phase Chat LCP IPCP CCP tun command debug
Jun 11 07:37:00 bee ppp[9076]: tun0: Command: dsl: set ifaddr 10.0.0.1/0 10.0.0.2/0 255.255.255.0 0.0.0.0
Jun 11 07:37:00 bee ppp[9076]: tun0: Command: dsl: set device PPPoE:xl0
Jun 11 07:37:00 bee ppp[9076]: tun0: Command: dsl: set authname tmiddleton_at_adsl
Jun 11 07:37:00 bee ppp[9076]: tun0: Command: dsl: set authkey ********
Jun 11 07:37:00 bee ppp[9076]: tun0: Command: dsl: set dial
Jun 11 07:37:00 bee ppp[9076]: tun0: Command: dsl: set login
Jun 11 07:37:00 bee ppp[9076]: tun0: Command: dsl: enable lqr
Jun 11 07:37:00 bee ppp[9076]: tun0: Command: dsl: set lqrperiod 5
Jun 11 07:37:00 bee ppp[9076]: tun0: Command: dsl: set speed sync
Jun 11 07:37:00 bee ppp[9076]: tun0: Command: dsl: set cd 5
Jun 11 07:37:00 bee ppp[9076]: tun0: Command: dsl: set ctsrts off
Jun 11 07:37:00 bee ppp[9076]: tun0: Command: dsl: add default HISADDR
Jun 11 07:37:00 bee ppp[9076]: tun0: Debug: wrote -1: cmd = Add, dst = 0.0.0.0/0, gateway = 10.0.0.2
Jun 11 07:37:00 bee ppp[9076]: tun0: Phase: bundle: Establish
Jun 11 07:37:00 bee ppp[9076]: tun0: Phase: deflink: closed -> opening
Jun 11 07:37:00 bee ppp[9076]: tun0: Debug: List of netgraph node ``xl0:'' (id 1) hooks:
Jun 11 07:37:00 bee ppp[9076]: tun0: Debug:   Found orphans -> ethernet
Jun 11 07:37:00 bee ppp[9076]: tun0: Debug: Connecting netgraph socket .:tun0 -> [4]::tun0
Jun 11 07:37:00 bee ppp[9076]: tun0: Debug: Sending PPPOE_CONNECT to .:tun0
Jun 11 07:37:00 bee ppp[9076]: tun0: Debug: Found the following interfaces:
Jun 11 07:37:00 bee ppp[9076]: tun0: Debug:  Index 1, name "xl0"
Jun 11 07:37:00 bee ppp[9076]: tun0: Debug:  Index 2, name "rl0"
Jun 11 07:37:00 bee ppp[9076]: tun0: Debug:  Index 3, name "lo0"
Jun 11 07:37:00 bee ppp[9076]: tun0: Debug:  Index 4, name "tun0"
Jun 11 07:37:00 bee ppp[9076]: tun0: Phase: deflink: Connected!
Jun 11 07:37:00 bee ppp[9076]: tun0: Phase: deflink: opening -> dial
Jun 11 07:37:00 bee ppp[9076]: tun0: Chat: deflink: Dial attempt 1 of 1
Jun 11 07:37:00 bee ppp[9076]: tun0: Phase: deflink: dial -> carrier
Jun 11 07:37:00 bee ppp[9076]: tun0: Debug: Waiting for carrier
Jun 11 07:37:03 bee last message repeated 4 times
Jun 11 07:37:04 bee ppp[9076]: tun0: Phase: deflink: Disconnected!
Jun 11 07:37:04 bee ppp[9076]: tun0: Phase: deflink: carrier -> hangup
Jun 11 07:37:04 bee ppp[9076]: tun0: Debug: deflink: Close

monitoring the interface (tcpdump -e -i xl0 not ip) one can see:

07:47:59.950033 0:1:3:23:ee:f4 Broadcast 8863 32: PPPoE PADI [Host-Uniq UTF8]
07:48:01.949617 0:1:3:23:ee:f4 Broadcast 8863 32: PPPoE PADI [Host-Uniq UTF8]

I'd post my config if it would help to see it; but most of it can be
seen in the log above, and it's really very simple and always had
worked, so i'm not sure it's relevant in this case.

-- 
Tim Middleton | Cain Gang Ltd | I'd ha' been a better man all my life if
x_at_veX.net     | www.Vex.Net   | I'd known there were things like this. (CSL)