PPPD via GPRS disconnection problem

This is a discussion on PPPD via GPRS disconnection problem within the PPP forums, part of the Protocols category; The problem: I start pppd, the connection comes up, if-up is run. After that I get "No response to 3 echo-requests" and the link is disconnected. I have tried using ...

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  #1  
Old 10-02-2007, 10:51 AM
Default PPPD via GPRS disconnection problem

The problem:

I start pppd, the connection comes up, if-up is run. After that I get
"No response to 3 echo-requests" and the link is disconnected. I have
tried using Fedora and an XScale linux with the same result.

The log:

CONNECT
Serial connection established.
using channel 4
Using interface ppp0
Connect: ppp0 <--> /dev/ttyS2
sent [LCP ConfReq id=0x1 ]
rcvd [LCP ConfReq id=0x1 ]
sent [LCP ConfAck id=0x1 ]
rcvd [LCP ConfAck id=0x1 ]
sent [LCP EchoReq id=0x0 magic=0x0]
sent [PAP AuthReq id=0x1 user="gprs" password=]
rcvd [LCP CodeRej id=0x3 09 00 00 08 00 00 00 00]
LCP: Rcvd Code-Reject for code 9, id 0
rcvd [PAP AuthAck id=0x1 ""]
sent [IPCP ConfReq id=0x1 0.0.0.0>]
rcvd [IPCP ConfReq id=0x1 ]
sent [IPCP ConfAck id=0x1 ]
rcvd [IPCP ConfNak id=0x1
]
sent [IPCP ConfReq id=0x2
]
rcvd [IPCP ConfAck id=0x2
]
local IP address 10.16.87.125
remote IP address 10.16.87.124
primary DNS address 217.174.65.61
secondary DNS address 217.174.65.62
Script /etc/ppp/ip-up started (pid 165)
Script /etc/ppp/ip-up finished (pid 165), status = 0x0
sent [LCP EchoReq id=0x1 magic=0x0]
rcvd [LCP CodeRej id=0x4 09 01 00 08 00 00 00 00]
LCP: Rcvd Code-Reject for code 9, id 1
sent [LCP EchoReq id=0x2 magic=0x0]
rcvd [LCP CodeRej id=0x5 09 02 00 08 00 00 00 00]
LCP: Rcvd Code-Reject for code 9, id 2
No response to 3 echo-requests
Serial link appears to be disconnected.
Script /etc/ppp/ip-down started (pid 168)
sent [LCP TermReq id=0x2 "Peer not responding"]
rcvd [LCP TermAck id=0x2]
Connection terminated.

================================================== =============

When I run ifconfig and ping from ip-up I get the following result:

ppp0 Link encap:Point-to-Point Protocol
inet addr:10.14.68.19 P-t-P:10.14.68.18
Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:576 Metric:1
RX packets:3 errors:0 dropped:0 overruns:0 frame:0
TX packets:3 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3
RX bytes:54 (54.0 b) TX bytes:54 (54.0 b)

PING www.sunet.se (192.36.125.18): 56 data bytes
64 bytes from 192.36.125.18: icmp_seq=0 ttl=236 time=648.8 ms

================================================== =============

/etc/ppp/options:

debug
nodetach
defaultroute
crtscts
mru 576
mtu 576
lock
lcp-echo-interval 5
lcp-echo-failure 3
/dev/ttyS2
38400
connect "/usr/sbin/chat -S -f /etc/ppp/chat.script"
nomagic
asyncmap 0
novj
user gprs
noipdefault
ipcp-accept-local
usepeerdns
noccp
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  #2  
Old 10-02-2007, 10:51 AM
Default Re: PPPD via GPRS disconnection problem


Krister Renaud wrote:
> The problem:
>
> I start pppd, the connection comes up, if-up is run. After that I get
> "No response to 3 echo-requests" and the link is disconnected. I have
> tried using Fedora and an XScale linux with the same result.
>
> The log:
>
> CONNECT
> Serial connection established.
> using channel 4
> Using interface ppp0
> Connect: ppp0 <--> /dev/ttyS2
> sent [LCP ConfReq id=0x1 ]
> rcvd [LCP ConfReq id=0x1 ]
> sent [LCP ConfAck id=0x1 ]
> rcvd [LCP ConfAck id=0x1 ]
> sent [LCP EchoReq id=0x0 magic=0x0]
> sent [PAP AuthReq id=0x1 user="gprs" password=]
> rcvd [LCP CodeRej id=0x3 09 00 00 08 00 00 00 00]
> LCP: Rcvd Code-Reject for code 9, id 0
> rcvd [PAP AuthAck id=0x1 ""]
> sent [IPCP ConfReq id=0x1 > 0.0.0.0>]
> rcvd [IPCP ConfReq id=0x1 ]
> sent [IPCP ConfAck id=0x1 ]
> rcvd [IPCP ConfNak id=0x1
> ]
> sent [IPCP ConfReq id=0x2
> ]
> rcvd [IPCP ConfAck id=0x2
> ]
> local IP address 10.16.87.125
> remote IP address 10.16.87.124
> primary DNS address 217.174.65.61
> secondary DNS address 217.174.65.62
> Script /etc/ppp/ip-up started (pid 165)
> Script /etc/ppp/ip-up finished (pid 165), status = 0x0
> sent [LCP EchoReq id=0x1 magic=0x0]
> rcvd [LCP CodeRej id=0x4 09 01 00 08 00 00 00 00]
> LCP: Rcvd Code-Reject for code 9, id 1
> sent [LCP EchoReq id=0x2 magic=0x0]
> rcvd [LCP CodeRej id=0x5 09 02 00 08 00 00 00 00]
> LCP: Rcvd Code-Reject for code 9, id 2
> No response to 3 echo-requests
> Serial link appears to be disconnected.
> Script /etc/ppp/ip-down started (pid 168)
> sent [LCP TermReq id=0x2 "Peer not responding"]
> rcvd [LCP TermAck id=0x2]
> Connection terminated.
>
> ================================================== =============
>
> When I run ifconfig and ping from ip-up I get the following result:
>
> ppp0 Link encap:Point-to-Point Protocol
> inet addr:10.14.68.19 P-t-P:10.14.68.18
> Mask:255.255.255.255
> UP POINTOPOINT RUNNING NOARP MULTICAST MTU:576 Metric:1
> RX packets:3 errors:0 dropped:0 overruns:0 frame:0
> TX packets:3 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:3
> RX bytes:54 (54.0 b) TX bytes:54 (54.0 b)
>
> PING www.sunet.se (192.36.125.18): 56 data bytes
> 64 bytes from 192.36.125.18: icmp_seq=0 ttl=236 time=648.8 ms
>
> ================================================== =============
>
> /etc/ppp/options:
>
> debug
> nodetach
> defaultroute
> crtscts
> mru 576
> mtu 576
> lock
> lcp-echo-interval 5
> lcp-echo-failure 3
> /dev/ttyS2
> 38400
> connect "/usr/sbin/chat -S -f /etc/ppp/chat.script"
> nomagic
> asyncmap 0
> novj
> user gprs
> noipdefault
> ipcp-accept-local
> usepeerdns
> noccp


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  #3  
Old 10-02-2007, 10:51 AM
Default Re: PPPD via GPRS disconnection problem

In article <61b44f09.0504080525.63a047b9@posting.google.com>, Krister
Renaud wrote:
> The problem:
>
> I start pppd, the connection comes up, if-up is run. After that I get
> "No response to 3 echo-requests" and the link is disconnected. I have
> tried using Fedora and an XScale linux with the same result.


Disconnection is the problem?

The error message is a good hint. The other end of the PPP link, most
likely the phone you're using, does not support lcp-echo-requests and
-replies (for really no good reason as the serial links aren't that
reliable).

> lcp-echo-interval 5
> lcp-echo-failure 3


Setting these to zero will effectively disable echo requests and
replies. man pppd will tell more.

-Mikko
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  #4  
Old 10-02-2007, 10:51 AM
Default Re: PPPD via GPRS disconnection problem

Mikko Rapeli wrote:
> In article <61b44f09.0504080525.63a047b9@posting.google.com>, Krister
> Renaud wrote:
>> The problem:
>>
>> I start pppd, the connection comes up, if-up is run. After that I get
>> "No response to 3 echo-requests" and the link is disconnected. I have
>> tried using Fedora and an XScale linux with the same result.


> Disconnection is the problem?


> The error message is a good hint. The other end of the PPP link, most
> likely the phone you're using, does not support lcp-echo-requests and
> -replies (for really no good reason as the serial links aren't that
> reliable).


It also violates RFC 1661:

Upon reception of an Echo-Request in the LCP Opened state, an
Echo-Reply MUST be transmitted.

But cell-phone PPP is a different beast from normal PPP. I'm not
a PPP implementor and don't even have a cell-phone but believe the
following paragraph is a reasonable description of what goes on.

The PPP link terminates in the cell-phone, which has it's own PPP
implementation. The outgoing PPP data are forwarded over the RF link
using a different protocol, and the process is reversed for incoming
data from the RF link so it can be sent to the device connected to
the cell-phone using PPP.

>> lcp-echo-interval 5
>> lcp-echo-failure 3


> Setting these to zero will effectively disable echo requests and
> replies. man pppd will tell more.


Or simply remove them.

--
Clifford Kite Email: "echo xvgr_yvahk-ccc@ri1.arg|rot13"
PPP-Q&A links, downloads: http://ckite.no-ip.net/
/* I hear and I forget. I see and I remember. I do and I understand.
--Confucius, 551-479 BC */
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  #5  
Old 10-02-2007, 10:51 AM
Default Re: PPPD via GPRS disconnection problem

Mikko Rapeli writes:

>In article <61b44f09.0504080525.63a047b9@posting.google.com>, Krister
>Renaud wrote:
>> The problem:
>>
>> I start pppd, the connection comes up, if-up is run. After that I get
>> "No response to 3 echo-requests" and the link is disconnected. I have
>> tried using Fedora and an XScale linux with the same result.


>Disconnection is the problem?


>The error message is a good hint. The other end of the PPP link, most
>likely the phone you're using, does not support lcp-echo-requests and
>-replies (for really no good reason as the serial links aren't that
>reliable).


>> lcp-echo-interval 5
>> lcp-echo-failure 3


>Setting these to zero will effectively disable echo requests and
>replies. man pppd will tell more.


Agreed. There are two possibilities-- the other end is disconnected or the
othe end does not respond to echo requests. Disable echo requests, and see
if things work. If they do, the explanation is the second one. If they do
not, then the first is the more likely. From the log output it looks like
things should work.

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  #6  
Old 10-02-2007, 10:51 AM
Default Re: PPPD via GPRS disconnection problem

In article ,
Bill Unruh wrote:
>Mikko Rapeli writes:
>
>>In article <61b44f09.0504080525.63a047b9@posting.google.com>, Krister
>>Renaud wrote:
>>> The problem:
>>>
>>> I start pppd, the connection comes up, if-up is run. After that I get
>>> "No response to 3 echo-requests" and the link is disconnected. I have
>>> tried using Fedora and an XScale linux with the same result.

>
>>Disconnection is the problem?

>
>>The error message is a good hint. The other end of the PPP link, most
>>likely the phone you're using, does not support lcp-echo-requests and
>>-replies (for really no good reason as the serial links aren't that
>>reliable).

>
>>> lcp-echo-interval 5
>>> lcp-echo-failure 3

>
>>Setting these to zero will effectively disable echo requests and
>>replies. man pppd will tell more.

>
>Agreed. There are two possibilities-- the other end is disconnected or the
>othe end does not respond to echo requests.


It's clear from the original posting that the other end doesn't do echo
requests:

>> sent [LCP EchoReq id=0x2 magic=0x0]
>> rcvd [LCP CodeRej id=0x5 09 02 00 08 00 00 00 00]
>> LCP: Rcvd Code-Reject for code 9, id 2


At least it did a CodeRej[ect] instead of just ignoring you. ;^)

>Disable echo requests, and see
>if things work. If they do, the explanation is the second one. If they do
>not, then the first is the more likely. From the log output it looks like
>things should work.


========= For LAN/WAN Protocol Analysis, check out PacketView Pro! =========
Patrick Klos Email: patrick@klos.com
Klos Technologies, Inc. Web: http://www.klos.com/
==== I don't think infinity is as big as it seems - P.Klos, 20-Mar-2005 ====

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