PAP/CHAP in PDP context of MC8705


#1

Hi all,

I am using MC8705 and running Linux OS. I have 2 SIM with AT&T wireless network - One SIM doesn’t need to set username and password, the other requires username/passowrd to log on.

SIM without username/paswword works well - but the SIM with username/password always fail to connect to AT&T PPP server. Contact with AT&T and they told me that Sierra modem does send PAP/CHAP authentication in the PDP context, but from PPPd log file, I saw PPPd has sent CHAP authentication and always got OK message from server. And immediately after authentication phase, modem hung up by the peer.

I wonder Sierra modem has PPP running inside the modem, and it handles PPP negotiation with host instead of forwarding to PPP server. That is the reason why PPPd from host got back OK CHAP message but in fact it is not.

My question is that there is any AT command to set PAP/CHAP authentication in MC8705 ?

Any help would be greatly appreciated.

Thanks,


#2

Hi,

There is a command “AT$QCDPP” ,used to set/report PDP-IP connection authentication parameters.
AT$QCPDPP=, <auth_type>, ,

<auth_type>:
• 0 = None—Username and password not required
• 1 = PAP—Username and password accepted
• 2 = CHAP—Username and password (secret) accepted

Please refer to Airprime UMTS Extended AT guide,for more details.

Thanks.


#3

Thank you Rex_alex.
Yes I did try that command to set CHAP authentication but it doesn’t help. :frowning:


#4

Working with AT&T support, I am been told the MC8705 has sent incorrect CHAP information if modem activates PDP context via ATD99**1 command, and PPP mode.
=== ================================
CHAP failure due to Value and hostname

Activate PDP context with ATDT 99**1#

Octet114 CHAP Challenge

00000001 Code (1) Challenge
00000001 Identifier 1
… Length 35
00010000 Value Size 16
… Value 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
… Name UMTS_CHAP_SRVR

Octet149 Protocol ID

… Protocol ID (49699) CHAP Challenge Handshake Authentication Protocol
00101000 Parameter length 40

Octet152 CHAP Response

00000010 Code (2) Response
00000001 Identifier 1
… Length 40
00010000 Value Size 16
… Value 7E CE 08 54 22 0C 9A 8F 8F C1 DB 07 66 33 C2 2F
… Name usertest

If I activate via AT+CGACT=1,1 then CHAP authentication is OK. The difference of those 2 activation methods are CHAP server name and Value in CHAP challenge, which is sent from MC8705.

And here is the trace of success authentication

=== ==============================
CHAP authen OK
Activate PDP context with AT+CGACT=1

Octet114 CHAP Challenge

00000001 Code (1) Challenge
00000000 Identifier 0
… Length 33
00010000 Value Size 16
… Value 0B AB 8B 8B 0B AB 8B 8B 0B AB 8B 8B 0B AB 8B 8B
… Name umts-net.net

Octet147 Protocol ID

… Protocol ID (49699) CHAP Challenge Handshake Authentication Protocol
00101000 Parameter length 40

Octet150 CHAP Response

00000010 Code (2) Response
00000000 Identifier 0
… Length 40
00010000 Value Size 16
… Value 1C 1A 88 CA 45 B6 79 7A 89 02 CA 77 35 79 35 A1

Look like this is a bug in MC8705 firmware. I have contacted to Sierra but it takes so long . Any comment is greatly appreciated.

May I know anyone has encountered the same problem as mine when connect to Wireless network with authentication ON.

Thanks.