[RP-PPPoE] RFC 4638 does not work?

[Mike van Goor]

Hello,

I am new to this list, so hi.

I have a corporate internet connection through a local isp called KPN in 
the netherlands.
They state in their documentation they support RFC 4638.

So I did some checking and found that rp-pppoe 3.11 with pppd 2.4.7 
would be able to support that.
I am running debian testing and manually build pppd 2.4.7 and rp-pppoe 
3.11 from source.
Finding relevant information is a bit tricky, but this is what I configured:

/etc/network/interfaces
iface eth3 inet manual
     pre-up ip link set dev eth3 mtu 1508

I also tried:
iface eth3 inet manual
     mtu 1508

I do see the new mtu on the interface:
5: eth3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1508 qdisc pfifo_fast 
state UP mode DEFAULT group default qlen 1000
     link/ether 00:23:8b:03:d6:c0 brd ff:ff:ff:ff:ff:ff

/etc/ppp/pppoe.conf:
ETH='eth3'
USER='kpn'
DEMAND=no
DNSTYPE=SERVER
PEERDNS=yes
DNS1=
DNS2=
DEFAULTROUTE=yes
CONNECT_TIMEOUT=30
CONNECT_POLL=2
ACNAME=
SERVICENAME=
PING="."
CF_BASE=`basename $CONFIG`
PIDFILE="/var/run/$CF_BASE-pppoe.pid"
SYNCHRONOUS=no
CLAMPMSS=1412
LCP_INTERVAL=20
LCP_FAILURE=3
PPPOE_TIMEOUT=80
FIREWALL=NONE
LINUX_PLUGIN=/etc/ppp/plugins/rp-pppoe.so
PPPOE_EXTRA=""
PPPD_EXTRA="debug"
MTU=1500
MRU=1500

syslog:
Feb  4 15:43:29 dgw01 pppd[26365]: sent [LCP TermReq id=0x2 "User request"]
Feb  4 15:43:29 dgw01 pppd[26365]: rcvd [LCP TermAck id=0x2]
Feb  4 15:43:35 dgw01 pppd[26947]: PADS: Service-Name: ''
Feb  4 15:43:35 dgw01 pppd[26947]: using channel 22
Feb  4 15:43:35 dgw01 pppd[26947]: sent [LCP ConfReq id=0x1 <mru 1492> 
<magic 0xb340b80a>]
Feb  4 15:43:36 dgw01 pppd[26947]: rcvd [LCP ConfReq id=0x1 <mru 1492> 
<auth pap> <magic 0x1fb8b2d8>]
Feb  4 15:43:36 dgw01 pppd[26947]: sent [LCP ConfAck id=0x1 <mru 1492> 
<auth pap> <magic 0x1fb8b2d8>]
Feb  4 15:43:36 dgw01 pppd[26947]: rcvd [LCP ConfAck id=0x1 <mru 1492> 
<magic 0xb340b80a>]
Feb  4 15:43:36 dgw01 pppd[26947]: sent [LCP EchoReq id=0x0 
magic=0xb340b80a]
Feb  4 15:43:36 dgw01 pppd[26947]: sent [PAP AuthReq id=0x1 user="kpn" 
password=<hidden>]
Feb  4 15:43:36 dgw01 pppd[26947]: rcvd [LCP EchoRep id=0x0 
magic=0x1fb8b2d8]
Feb  4 15:43:37 dgw01 pppd[26947]: rcvd [PAP AuthAck id=0x1 ""]
Feb  4 15:43:37 dgw01 pppd[26947]: sent [IPCP ConfReq id=0x1 <addr 
0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Feb  4 15:43:37 dgw01 pppd[26947]: rcvd [IPCP ConfReq id=0x1 <addr 
62.12.4.23>]
Feb  4 15:43:37 dgw01 pppd[26947]: sent [IPCP ConfAck id=0x1 <addr 
62.12.4.23>]
Feb  4 15:43:37 dgw01 pppd[26947]: rcvd [IPCP ConfNak id=0x1 <addr 
77.61.11.209> <ms-dns1 194.151.228.18> <ms-dns2 194.151.228.34>]
Feb  4 15:43:37 dgw01 pppd[26947]: sent [IPCP ConfReq id=0x2 <addr 
77.61.11.209> <ms-dns1 194.151.228.18> <ms-dns2 194.151.228.34>]
Feb  4 15:43:37 dgw01 pppd[26947]: rcvd [IPCP ConfAck id=0x2 <addr 
77.61.11.209> <ms-dns1 194.151.228.18> <ms-dns2 194.151.228.34>]

As you can see the first action I see is "mru 1492" as if the entire 
configuration is ignored.

If anybody could be direct towards a solution or something I might have 
missed please :)

Also if anyone knows how to get more debug information, please do.

Thanks.

Kind regards,
Mike van Goor