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DSL Line - PPPoE (-current) and tcpdump truncated-ip



Hi,

Please forgive me if it's absolutely wrong to post to the mailing list and
the newsgroup, but I haven't gotten any response off of the newsgroup, so
I thought I'd try here...

I am trying to configure a client's system for DSL access using PPPoE.

This is a 2.7-patch system, with the ppp and pppoe from the -current. They
compile up absolutely no problem.

The PPoE component appears to be working 100 %.

There is a problem with reliability and throughput ( which I equate with
truncated packets ).

I am getting truncated IP packets when I do a TCPDUMP on the network
interface running off to the DSL modem.

There is one reference to this in the mailing list archives, but no
solution.

I SUSPECT that it is related to the MRU being wrong, but the ISP is really
being a dick ( and I don't have a choice, my client selected them )...

The PPPoE occurs, and the PAP handshaking establishes a link with a
MRU of 1492, then performs authentication.

The authentication causes a re-negotiation of the PAP paramaters, and at
this point, the MRU/MTU (appears) to be agreed upon as 1500.  WTF??

I have a feeling that this is the problem, but really don't know...

I had to turn off LQR just so the link would stay up.  If LQR was enabled,
just idling, the PPP link would disconnect & restablish, presumable
because the three of the LQR packets would get munged and the LQR would 
perform the disconnect.

Trying to max out the pipe causes repeated PPP disconnects as well

Thanks for ANY suggestions...
----------------------------------------------------------------------
TCP Dump example
----------------------------------------------------------------------
15:39:55.857170 PPPoE-Session
        code Session, version 1, type 1, id 0x001a, length 178
        IP: truncated-ip - 102 bytes missing!b.gtld-servers.net.domain >
xyz.domain:  47546- 1/3/3 A

----------------------------------------------------------------------
PPP Log file
----------------------------------------------------------------------
Sep 13 01:23:39 xyz ppp[29101]: Phase: Using interface: tun0
Sep 13 01:23:39 xyz ppp[29101]: Phase: deflink: Created in closed state
Sep 13 01:24:54 xyz ppp[29101]: Phase: Listening at port 3000.
Sep 13 01:24:54 xyz ppp[14208]: Phase: PPP Started (ddial mode).
Sep 13 01:24:54 xyz ppp[14208]: Phase: bundle: Establish
Sep 13 01:24:54 xyz ppp[14208]: Phase: deflink: closed -> opening
Sep 13 01:24:55 xyz ppp[14208]: Phase: deflink: Connected!
Sep 13 01:24:55 xyz ppp[14208]: Phase: deflink: opening -> dial
Sep 13 01:24:55 xyz ppp[14208]: Phase: deflink: dial -> carrier
Sep 13 01:24:55 xyz ppp[14208]: Phase: deflink: carrier -> login
Sep 13 01:24:55 xyz ppp[14208]: Phase: deflink: login -> lcp
Sep 13 01:24:55 xyz ppp[14208]: LCP: FSM: Using "deflink" as a transport

Sep 13 01:24:55 xyz ppp[14208]: LCP: deflink: State change Initial -->
Closed
Sep 13 01:24:55 xyz ppp[14208]: LCP: deflink: State change Closed -->
Stopped
Sep 13 01:24:56 xyz ppp[14208]: LCP: deflink: LayerStart
Sep 13 01:24:56 xyz ppp[14208]: LCP: deflink: SendConfigReq(1) state =
Stopped
Sep 13 01:24:56 xyz ppp[14208]: LCP:  MRU[4] 1492
Sep 13 01:24:56 xyz ppp[14208]: LCP:  MAGICNUM[6] 0x3b3caede
Sep 13 01:24:56 xyz ppp[14208]: LCP: deflink: State change Stopped -->
Req-Sent
Sep 13 01:24:56 xyz ppp[14208]: LCP: deflink: RecvConfigReq(7) state =
Req-Sent
Sep 13 01:24:56 xyz ppp[14208]: LCP:  MRU[4] 1492
Sep 13 01:24:56 xyz ppp[14208]: LCP:  AUTHPROTO[4] 0xc023 (PAP)
Sep 13 01:24:56 xyz ppp[14208]: LCP:  MAGICNUM[6] 0x009bcd3a
Sep 13 01:24:56 xyz ppp[14208]: LCP: deflink: SendConfigAck(7) state =
Req-Sent
Sep 13 01:24:56 xyz ppp[14208]: LCP:  MRU[4] 1492
Sep 13 01:24:56 xyz ppp[14208]: LCP:  AUTHPROTO[4] 0xc023 (PAP)
Sep 13 01:24:56 xyz ppp[14208]: LCP:  MAGICNUM[6] 0x009bcd3a
Sep 13 01:24:56 xyz ppp[14208]: LCP: deflink: State change Req-Sent -->
Ack-Sent
Sep 13 01:24:56 xyz ppp[14208]: LCP: deflink: RecvConfigAck(1) state =
Ack-Sent
Sep 13 01:24:56 xyz ppp[14208]: LCP: deflink: State change Ack-Sent -->
Opened
Sep 13 01:24:56 xyz ppp[14208]: LCP: deflink: LayerUp
Sep 13 01:24:56 xyz ppp[14208]: Phase: bundle: Authenticate
Sep 13 01:24:56 xyz ppp[14208]: Phase: deflink: his = PAP, mine = none
Sep 13 01:24:56 xyz ppp[14208]: Phase: Pap Output: abc@xyz ********
Sep 13 01:24:57 xyz ppp[14208]: LCP: deflink: RecvConfigReq(2) state =
Opened
Sep 13 01:24:57 xyz ppp[14208]: LCP: deflink: LayerDown
Sep 13 01:24:57 xyz ppp[14208]: LCP:  AUTHPROTO[4] 0xc023 (PAP)
Sep 13 01:24:57 xyz ppp[14208]: LCP:  MAGICNUM[6] 0x547172c3
Sep 13 01:24:57 xyz ppp[14208]: LCP: deflink: SendConfigReq(2) state =
Opened
Sep 13 01:24:57 xyz ppp[14208]: LCP:  MRU[4] 1492
Sep 13 01:24:57 xyz ppp[14208]: LCP:  MAGICNUM[6] 0x77a5d801
Sep 13 01:24:57 xyz ppp[14208]: LCP: deflink: SendConfigAck(2) state =
Opened
Sep 13 01:24:57 xyz ppp[14208]: LCP:  AUTHPROTO[4] 0xc023 (PAP)
Sep 13 01:24:57 xyz ppp[14208]: LCP:  MAGICNUM[6] 0x547172c3
Sep 13 01:24:57 xyz ppp[14208]: LCP: deflink: State change Opened -->
Ack-Sent
Sep 13 01:24:57 xyz ppp[14208]: LCP: deflink: RecvConfigNak(2) state =
Ack-Sent
Sep 13 01:24:57 xyz ppp[14208]: LCP:  MRU[4] 1500
Sep 13 01:24:57 xyz ppp[14208]: LCP: deflink: SendConfigReq(3) state =
Ack-Sent
Sep 13 01:24:57 xyz ppp[14208]: LCP:  MRU[4] 1500
Sep 13 01:24:57 xyz ppp[14208]: LCP:  MAGICNUM[6] 0x77a5d801
Sep 13 01:24:57 xyz ppp[14208]: LCP: deflink: RecvConfigAck(3) state =
Ack-Sent
Sep 13 01:24:57 xyz ppp[14208]: LCP: deflink: State change Ack-Sent -->
Opened
Sep 13 01:24:57 xyz ppp[14208]: LCP: deflink: LayerUp
Sep 13 01:24:57 xyz ppp[14208]: Phase: deflink: his = PAP, mine = none
Sep 13 01:24:57 xyz ppp[14208]: Phase: Pap Output: abc@xyz ********
Sep 13 01:24:57 xyz ppp[14208]: Phase: Pap Input: SUCCESS ()
Sep 13 01:24:57 xyz ppp[14208]: Phase: deflink: lcp -> open
Sep 13 01:24:57 xyz ppp[14208]: Phase: bundle: Network
Sep 13 01:24:57 xyz ppp[14208]: LCP: deflink: RecvProtocolRej(3) state =
Opened
Sep 13 01:24:57 xyz ppp[14208]: LCP: deflink: -- Protocol 0x80fd
(Compression Control Protocol) was rejected!
Sep 13 01:24:58 xyz ppp[14208]: LCP: deflink: RecvEchoRequest(1) state =
Opened
Sep 13 01:24:58 xyz ppp[14208]: LCP: deflink: SendEchoReply(1) state =
Opened
Sep 13 01:25:08 xyz ppp[14208]: LCP: deflink: RecvEchoRequest(2) state =
Opened
Sep 13 01:25:08 xyz ppp[14208]: LCP: deflink: SendEchoReply(2) state =
Opened


----------------------------------------------------------------------
LCP Configuration
----------------------------------------------------------------------
$ pppctl 3000
Password:
PPP ON xyz> show lcp
deflink: LCP [Opened]
 his side: MRU 1492, ACCMAP ffffffff, PROTOCOMP off, ACFCOMP off,
           MAGIC 547172c3, MRRU 0, SHORTSEQ off, REJECT 0000
 my  side: MRU 1500, ACCMAP 00000000, PROTOCOMP off, ACFCOMP off,
           MAGIC 77a5d801, MRRU 0, SHORTSEQ on, REJECT 0000

 Defaults: MRU = 1492, ACCMAP = 00000000
           LQR period = 30s, Open Mode = active (delay 1s)
           FSM retry = 3s, max 5 Config REQs, 5 Term REQs
    Ident:

 Negotiation:
           ACFCOMP =   disabled & denied
           CHAP =      disabled & accepted
           MSCHAP =    disabled & accepted
           LANMan =    disabled & accepted
           LQR =       disabled & denied
           PAP =       disabled & accepted
           PROTOCOMP = disabled & accepted

PPP ON xyz> Connection closed
$ exit

Script done on Wed Sep 13 01:41:44 2000

----------------------------------------------------------------------
PPP Configuration file
----------------------------------------------------------------------

default:

dsl:
   set log lcp Phase Warning Error Alert

        set device "!/usr/sbin/pppoe -i vr1"
        set mtu 1492
        set mru 1492
        set speed sync
        disable lqr acfcomp protocomp
        deny acfcomp
 deny lqr
 set authname abc@xyz
 set authkey  XXXXXX
 add default hisaddr




-- 
	Steve Williams, Calgary, Alberta, Canada
	Genie Computer Systems Inc.
	steve@genie96.com

"A man doesn't begin to attain wisdom until he recognizes that he is 
 no longer indispensable."
- Admiral Richard E. Byrd ( 1888-1957 )