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Reload this Page Strange PPP/LCP exchanges with Verizon's EVDO network
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Old 11-30-2005, 04:48 PM   #1
leeyuiwah
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Registered: Aug 2004
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Strange PPP/LCP exchanges with Verizon's EVDO network

Hi,

I wonder if anyone observe the following strange behavior with
Verizon's EVDO network. I think this strange behavior showed up only
recently (I did not seem to see it before, say, a few months ago).

In the following discussion, "Local" refers to the pppd on my linux
machine, "Remote" refers to Verizon's EVDO network.

When Local tried to connect, it might succeed or fail. By looking at
the log (turned on with the "debug" option of pppd), I noticed that
Remote responded differently in the LCP exchange phase. There were
four different modes of respond. Apparently which mode Remote would
pick is undeterministic.

1. Remote never responded to Local's LCP ConfReq. The link
establishment would fail. (See log below -- Section 1)

2. Remote would propose CHAP, and then

2a. If Local ConfNak'ed with PAP, Remote would ignore that Nak, but it
proceeded to grant an IP address to Local. After some
time, Remote would terminate the link. (Log in Section 2a)

(This is notably different to the behavior with a Verizon 3G1x
network: In 3G1x, the normal and successful authentication
procedures are

- Remote ConfReq's with CHAP
- Local Nak's with PAP,
- Remote Ack's that PAP is okay,
- Local proceed with PAP, using <phone_num>@vzw3g.com/vzw as
nai/password, and then the authentication would succeed
and link would be buildup

We were using SierraWireless Aircard 555 for the 3G1x case)

2b. If Local attempted to use CHAP, using <phone_num>@vzw3g.com/vzw
as the nai/password, the CHAP authentication would failed. (Log
in Section 2b)

3. Remote would NOT propose CHAP, nor would Local propose PAP.
Essentially, there was no authentication in the LCP exchange (Local
would not send nai/password). The link COULD BE successfully
established. (Log in Section 3).

4. Same LCP exchange as in 3, but the link could NOT be built up
successfully. Local's pppd would think the link was up because
Remote granted an IP address, but no packets could be sent through.
After a while, Remote terminate the link (Log in Section 4).

As you can see, Local could establish a link only in case (3). It
would fail in all other cases.

I could use a script to try connection repeatedly. Eventually Local
would hit a case (3) and then establish a link. Although this works
around the problem, the connection time is much longer now (sometime
more than 10 minutes!)

I have similar experience in different New Jersey locations (Whippany,
Holmdel, Eatoncrest). The EVDO card that I am using is 5220.

I also tried using the same card on a Window 2000 machine in the same
locations. It seems that the card can usually establish a ppp link
without much trouble.

Clement

----------------------------------------------------------------------
Log Section 1: LCP Config Request Timeout

Nov 23 13:19:57 wer-ap3 pppd[4174]: pppd 2.4.1 started by root, uid 0
Nov 23 13:19:58 wer-ap3 chat[4175]: abort on (BUSY)
Nov 23 13:19:58 wer-ap3 chat[4175]: abort on (NO CARRIER)
Nov 23 13:19:58 wer-ap3 chat[4175]: send (ATZ^M)
Nov 23 13:19:58 wer-ap3 chat[4175]: expect (OK)
Nov 23 13:19:58 wer-ap3 chat[4175]: ATZ^M^M
Nov 23 13:19:58 wer-ap3 chat[4175]: OK
Nov 23 13:19:58 wer-ap3 chat[4175]: -- got it
Nov 23 13:19:58 wer-ap3 chat[4175]: send (ATDT#777^M)
Nov 23 13:19:58 wer-ap3 chat[4175]: timeout set to 75 seconds
Nov 23 13:19:58 wer-ap3 chat[4175]: expect (CONNECT)
Nov 23 13:19:58 wer-ap3 chat[4175]: ^M
Nov 23 13:20:16 wer-ap3 chat[4175]: ATDT#777^M^M
Nov 23 13:20:16 wer-ap3 chat[4175]: CONNECT
Nov 23 13:20:16 wer-ap3 chat[4175]: -- got it
Nov 23 13:20:16 wer-ap3 chat[4175]: send (CLIENT^M)
Nov 23 13:20:16 wer-ap3 pppd[4174]: Serial connection established.
Nov 23 13:20:16 wer-ap3 pppd[4174]: using channel 10
Nov 23 13:20:16 wer-ap3 pppd[4174]: Using interface ppp0
Nov 23 13:20:16 wer-ap3 pppd[4174]: Connect: ppp0 <--> /dev/modem
Nov 23 13:20:17 wer-ap3 pppd[4174]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x49e31b0c> <pcomp> <accomp>]
Nov 23 13:20:44 wer-ap3 last message repeated 9 times
Nov 23 13:20:47 wer-ap3 pppd[4174]: LCP: timeout sending Config-Requests
Nov 23 13:20:47 wer-ap3 pppd[4174]: Connection terminated.

----------------------------------------------------------------------
Log Section 2a: Remote proposed CHAP, ignored Local's Nak of PAP

Nov 23 11:16:16 wer-ap3 pppd[700]: rcvd [LCP ConfReq id=0x3 <mru 1500> <asyncmap 0x0> <auth chap MD5> <magic 0xd38cd26c> <pcomp> <accomp>]
Nov 23 11:16:16 wer-ap3 pppd[700]: sent [LCP ConfReq id=0xb <asyncmap 0x0> <magic 0x52bbde97> <pcomp> <accomp>]
Nov 23 11:16:16 wer-ap3 pppd[700]: sent [LCP ConfNak id=0x3 <auth pap>]
Nov 23 11:16:16 wer-ap3 pppd[700]: rcvd [LCP ConfAck id=0xb <asyncmap 0x0> <magic 0x52bbde97> <pcomp> <accomp>]
Nov 23 11:16:16 wer-ap3 pppd[700]: rcvd [LCP ConfReq id=0x4 <mru 1500> <asyncmap 0x0> <magic 0xd38cd26c> <pcomp> <accomp>]
Nov 23 11:16:16 wer-ap3 pppd[700]: sent [LCP ConfAck id=0x4 <mru 1500> <asyncmap 0x0> <magic 0xd38cd26c> <pcomp> <accomp>]
Nov 23 11:16:16 wer-ap3 pppd[700]: sent [IPCP ConfReq id=0x15 <addr 70.200.121.42> <ms-dns1 0.0.0.0> <ms-dns3 0.0.0.0>]
Nov 23 11:16:16 wer-ap3 pppd[700]: rcvd [IPCP ConfReq id=0x1 <addr 66.174.20.4>]
Nov 23 11:16:16 wer-ap3 pppd[700]: sent [IPCP ConfAck id=0x1 <addr 66.174.20.4>]
Nov 23 11:16:16 wer-ap3 pppd[700]: rcvd [IPCP ConfNak id=0x15 <ms-dns1 66.174.95.44> <ms-dns3 66.174.92.14>]
Nov 23 11:16:16 wer-ap3 pppd[700]: sent [IPCP ConfReq id=0x16 <addr 70.200.121.42> <ms-dns1 66.174.95.44> <ms-dns3 66.174.92.14>]
Nov 23 11:16:17 wer-ap3 pppd[700]: rcvd [IPCP ConfAck id=0x16 <addr 70.200.121.42> <ms-dns1 66.174.95.44> <ms-dns3 66.174.92.14>]
Nov 23 11:16:17 wer-ap3 pppd[700]: local IP address 70.200.121.42
Nov 23 11:16:17 wer-ap3 pppd[700]: remote IP address 66.174.20.4
Nov 23 11:16:17 wer-ap3 pppd[700]: primary DNS address 66.174.95.44
Nov 23 11:16:17 wer-ap3 pppd[700]: secondary DNS address 66.174.92.14
Nov 23 11:16:17 wer-ap3 pppd[700]: Script /etc/ppp/ip-up finished (pid 1869), status = 0x0
Nov 23 11:16:19 wer-ap3 pppd[700]: rcvd [LCP TermReq id=0x5]
Nov 23 11:16:19 wer-ap3 pppd[700]: LCP terminated by peer

----------------------------------------------------------------------
Log Section 2b: Remote proposed CHAP, Local attempted CHAP but failed

Nov 23 12:01:25 wer-ap3 pppd[3570]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x29130a14> <pcomp> <accomp>]
Nov 23 12:01:28 wer-ap3 pppd[3570]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x29130a14> <pcomp> <accomp>]
Nov 23 12:01:30 wer-ap3 pppd[3570]: rcvd [LCP ConfReq id=0x1 <mru 1500> <asyncmap 0x0> <auth chap MD5> <magic 0xfdebe5d2> <pcomp> <accomp>]
Nov 23 12:01:30 wer-ap3 pppd[3570]: sent [LCP ConfAck id=0x1 <mru 1500> <asyncmap 0x0> <auth chap MD5> <magic 0xfdebe5d2> <pcomp> <accomp>]
Nov 23 12:01:30 wer-ap3 pppd[3570]: rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x29130a14> <pcomp> <accomp>]
Nov 23 12:01:30 wer-ap3 pppd[3570]: rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x29130a14> <pcomp> <accomp>]
Nov 23 12:01:30 wer-ap3 pppd[3570]: rcvd [CHAP Challenge id=0x1 <ea4c7f1b5825d68d0fa9a0825843f91a>, name = ""]
Nov 23 12:01:30 wer-ap3 pppd[3570]: sent [CHAP Response id=0x1 <5685bd65514d6ed5462ecfe13954e747>, name = "732xxxxxxx@vzw3g.com"] <--- note I masked the actual phone number here in this log.
Nov 23 12:01:30 wer-ap3 pppd[3570]: rcvd [CHAP Failure id=0x1 ""]
Nov 23 12:01:30 wer-ap3 pppd[3570]: CHAP authentication failed
Nov 23 12:01:30 wer-ap3 pppd[3570]: sent [LCP TermReq id=0x2 "Failed to authenticate ourselves to peer"]
Nov 23 12:01:30 wer-ap3 pppd[3570]: rcvd [LCP TermReq id=0x2]
Nov 23 12:01:30 wer-ap3 pppd[3570]: sent [LCP TermAck id=0x2]
Nov 23 12:01:30 wer-ap3 pppd[3570]: rcvd [LCP TermAck id=0x2]
Nov 23 12:01:30 wer-ap3 pppd[3570]: Connection terminated.

----------------------------------------------------------------------
Log Section 3: No CHAP, No PAP, link was successfully established

Nov 23 13:47:16 wer-ap3 pppd[6075]: rcvd [LCP ConfReq id=0x1 <mru 1500> <asyncmap 0x0> <magic 0x9b7925a5> <pcomp> <accomp>]
Nov 23 13:47:16 wer-ap3 pppd[6075]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x303fa64f> <pcomp> <accomp>]
Nov 23 13:47:16 wer-ap3 pppd[6075]: sent [LCP ConfAck id=0x1 <mru 1500> <asyncmap 0x0> <magic 0x9b7925a5> <pcomp> <accomp>]
Nov 23 13:47:16 wer-ap3 pppd[6075]: rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x303fa64f> <pcomp> <accomp>]
Nov 23 13:47:16 wer-ap3 pppd[6075]: sent [IPCP ConfReq id=0x1 <addr 70.193.172.53> <ms-dns1 0.0.0.0> <ms-dns3 0.0.0.0>]
Nov 23 13:47:16 wer-ap3 pppd[6075]: rcvd [LCP DiscReq id=0x2 magic=0x9b7925a5]
Nov 23 13:47:16 wer-ap3 pppd[6075]: rcvd [IPCP ConfReq id=0x3 <addr 66.174.22.5>]
Nov 23 13:47:16 wer-ap3 pppd[6075]: sent [IPCP ConfAck id=0x3 <addr 66.174.22.5>]
Nov 23 13:47:16 wer-ap3 pppd[6075]: rcvd [IPCP ConfNak id=0x1 <addr 70.193.234.50> <ms-dns1 66.174.95.44> <ms-dns3 66.174.92.14>]
Nov 23 13:47:16 wer-ap3 pppd[6075]: sent [IPCP ConfReq id=0x2 <addr 70.193.234.50> <ms-dns1 66.174.95.44> <ms-dns3 66.174.92.14>]
Nov 23 13:47:16 wer-ap3 pppd[6075]: rcvd [IPCP ConfAck id=0x2 <addr 70.193.234.50> <ms-dns1 66.174.95.44> <ms-dns3 66.174.92.14>]
Nov 23 13:47:17 wer-ap3 pppd[6075]: local IP address 70.193.234.50
Nov 23 13:47:17 wer-ap3 pppd[6075]: remote IP address 66.174.22.5
Nov 23 13:47:17 wer-ap3 pppd[6075]: primary DNS address 66.174.95.44
Nov 23 13:47:17 wer-ap3 pppd[6075]: secondary DNS address 66.174.92.14

----------------------------------------------------------------------
Log Section 4: No CHAP, No PAP, but the link was not successfully
established.

Nov 23 13:36:12 wer-ap3 pppd[5442]: rcvd [LCP ConfReq id=0x1 <mru 1500> <asyncmap 0x0> <magic 0x820a938a> <pcomp> <accomp>]
Nov 23 13:36:12 wer-ap3 pppd[5442]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x98db361a> <pcomp> <accomp>]
Nov 23 13:36:12 wer-ap3 pppd[5442]: sent [LCP ConfAck id=0x1 <mru 1500> <asyncmap 0x0> <magic 0x820a938a> <pcomp> <accomp>]
Nov 23 13:36:12 wer-ap3 pppd[5442]: rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x98db361a> <pcomp> <accomp>]
Nov 23 13:36:12 wer-ap3 pppd[5442]: sent [IPCP ConfReq id=0x1 <addr 70.193.142.248> <ms-dns1 0.0.0.0> <ms-dns3 0.0.0.0>]
Nov 23 13:36:12 wer-ap3 pppd[5442]: rcvd [LCP DiscReq id=0x2 magic=0x820a938a]
Nov 23 13:36:12 wer-ap3 pppd[5442]: rcvd [IPCP ConfReq id=0x3 <addr 66.174.20.4>]
Nov 23 13:36:12 wer-ap3 pppd[5442]: sent [IPCP ConfAck id=0x3 <addr 66.174.20.4>]
Nov 23 13:36:12 wer-ap3 pppd[5442]: rcvd [IPCP ConfNak id=0x1 <addr 70.192.145.130> <ms-dns1 66.174.95.44> <ms-dns3 66.174.92.14>]
Nov 23 13:36:12 wer-ap3 pppd[5442]: sent [IPCP ConfReq id=0x2 <addr 70.192.145.130> <ms-dns1 66.174.95.44> <ms-dns3 66.174.92.14>]
Nov 23 13:36:12 wer-ap3 pppd[5442]: rcvd [IPCP ConfAck id=0x2 <addr 70.192.145.130> <ms-dns1 66.174.95.44> <ms-dns3 66.174.92.14>]
Nov 23 13:36:12 wer-ap3 pppd[5442]: local IP address 70.192.145.130
Nov 23 13:36:12 wer-ap3 pppd[5442]: remote IP address 66.174.20.4
Nov 23 13:36:12 wer-ap3 pppd[5442]: primary DNS address 66.174.95.44
Nov 23 13:36:12 wer-ap3 pppd[5442]: secondary DNS address 66.174.92.14
Nov 23 13:36:12 wer-ap3 pppd[5457]: Script /etc/ppp/ip-up started (pid 5458)
Nov 23 13:36:13 wer-ap3 named[458]: loading configuration from '/etc/named.conf'
Nov 23 13:36:13 wer-ap3 named[458]: no IPv6 interfaces found
Nov 23 13:36:13 wer-ap3 named[458]: listening on IPv4 interface ppp0, 70.192.145.130#53
Nov 23 13:36:13 wer-ap3 named[458]: no longer listening on 70.193.142.248#53
Nov 23 13:36:13 wer-ap3 logger: new_ip called with 70.192.145.130
Nov 23 13:36:13 wer-ap3 logger: Last backhaul IP address: 70.193.142.248
Nov 23 13:36:13 wer-ap3 logger: New backhaul IP address: 70.192.145.130

----------------------------------------------------------------------
 
  


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