CHAP Challenge/Response loop

#1 05-29-2008, 01:41 AM

Hi,
I am connecting from a Linux machine to an ISA server via ppp/pptp.
The connection handshake start correctly and the loop on the CHAP
Challenge/Response messages until it terminate the connection.
The connection log is show here:

[...]
rcvd [LCP ConfReq id=0x3 0x4fcf316c> [local:c8.29.40.c9.59.54.49.83.84.91.40.0c.5f.19.dc .7c.00.00.00.00]>]
sent [LCP ConfAck id=0x3 0x4fcf316c> [local:c8.29.40.c9.59.54.49.83.84.91.40.0c.5f.19.dc .7c.00.00.00.00]>]
sent [LCP EchoReq id=0x0 magic=0x84461837]
rcvd [CHAP Challenge id=0x0 <0bdba4f.....87ee44>, name = "HISNAME"]
sent [CHAP Response id=0x0 <971b80a0172......6fb804415600>, name =
"MYNAME"]
rcvd [CHAP Challenge id=0x1 <7d776e27....bc3304>, name = "HISNAME"]
sent [CHAP Response id=0x1 <093cb625afc....66c94e575f900>, name =
"MYNAME"]
rcvd [CHAP Challenge id=0x2 <7a551ee....6490d88>, name = "HISNAME"]
sent [CHAP Response id=0x2 , name = "MYNAME"]
rcvd [CHAP Challenge id=0x3 , name = "HISNAME"]
sent [CHAP Response id=0x3 <620e3b29.......7157000>, name = "MYNAME"]
rcvd [CHAP Challenge id=0x4 , name = "HISNAME"]
sent [CHAP Response id=0x4 , name = "MYNAME"]
rcvd [CHAP Challenge id=0x5 , name = "HISNAME"]
sent [CHAP Response id=0x5 <09b13fb.....80a900>, name = "MYNAME"]
rcvd [CHAP Challenge id=0x6 <528b60.....de7817>, name = "HISNAME"]
sent [CHAP Response id=0x6 <47a9cf3.....ff21900>, name = "MYNAME"]
rcvd [CHAP Challenge id=0x7 , name = "HISNAME"]
sent [CHAP Response id=0x7 , name = "MYNAME"]
rcvd [CHAP Challenge id=0x8 <1420....31b4>, name = "HISNAME"]
sent [CHAP Response id=0x8 , name = "MYNAME"]
rcvd [CHAP Challenge id=0x9 <40321a9....68b6>, name = "HISNAME"]
sent [CHAP Response id=0x9 , name = "MYNAME"]
rcvd [LCP TermReq id=0x4 "O\377777777171l\000<\37777777715t
\000\000\002\37777777716"]
LCP terminated by peer (OM-O1l^@ sent [LCP TermAck id=0x4]
rcvd [LCP TermReq id=0x5 "O\377777777171l\000<\37777777715t
\000\000\002\37777777716"]
sent [LCP TermAck id=0x5]
Connection terminated.
[...]

Does anyone have any idea of what is happening?

Thanks,
Giuseppe

#2 05-30-2008, 01:29 PM

Giuseppe Sacco writes:
> I am connecting from a Linux machine to an ISA server via ppp/pptp.
> The connection handshake start correctly and the loop on the CHAP
> Challenge/Response messages until it terminate the connection.
> The connection log is show here:
[...]
> Does anyone have any idea of what is happening?

You didn't include the complete LCP negotiations, but the behavior
you're describing is a classic symptom of a misconfigured ACCM
(asyncmap).

At a guess, since I can't see those LCP logs, one side asks for a
particular ACCM value, and you ask for a different one. There's
nothing technically wrong with that, but many inferior implementations
unfortunately have bugs in the way they handle differing transmit and
receive ACCM values.

Assuming all that is correct, the best solution would be to add an
"asyncmap" entry in your pppd configuration that sets your desired
ACCM value to the same as the peer's requested value.

--
James Carlson, Solaris Networking
Sun Microsystems / 35 Network Drive 71.232W Vox +1 781 442 2084
MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 1677

#3 08-08-2008, 01:42 PM

"Giuseppe Sacco" wrote in message
news:5f7f433f-cbf5-45f3-af54-e43706165e70@m36g2000hse.googlegroups.com...
> Hi,
> I am connecting from a Linux machine to an ISA server via ppp/pptp.
> The connection handshake start correctly and the loop on the CHAP
> Challenge/Response messages until it terminate the connection.
> The connection log is show here:
>
> [...]
> rcvd [LCP ConfReq id=0x3 > 0x4fcf316c> > [local:c8.29.40.c9.59.54.49.83.84.91.40.0c.5f.19.dc .7c.00.00.00.00]>]
> sent [LCP ConfAck id=0x3 > 0x4fcf316c> > [local:c8.29.40.c9.59.54.49.83.84.91.40.0c.5f.19.dc .7c.00.00.00.00]>]
> sent [LCP EchoReq id=0x0 magic=0x84461837]
> rcvd [CHAP Challenge id=0x0 <0bdba4f.....87ee44>, name = "HISNAME"]
> sent [CHAP Response id=0x0 <971b80a0172......6fb804415600>, name =
> "MYNAME"]
> rcvd [CHAP Challenge id=0x1 <7d776e27....bc3304>, name = "HISNAME"]
> sent [CHAP Response id=0x1 <093cb625afc....66c94e575f900>, name =
> "MYNAME"]
> rcvd [CHAP Challenge id=0x2 <7a551ee....6490d88>, name = "HISNAME"]
> sent [CHAP Response id=0x2 , name = "MYNAME"]
> rcvd [CHAP Challenge id=0x3 , name = "HISNAME"]
> sent [CHAP Response id=0x3 <620e3b29.......7157000>, name = "MYNAME"]
> rcvd [CHAP Challenge id=0x4 , name = "HISNAME"]
> sent [CHAP Response id=0x4 , name = "MYNAME"]
> rcvd [CHAP Challenge id=0x5 , name = "HISNAME"]
> sent [CHAP Response id=0x5 <09b13fb.....80a900>, name = "MYNAME"]
> rcvd [CHAP Challenge id=0x6 <528b60.....de7817>, name = "HISNAME"]
> sent [CHAP Response id=0x6 <47a9cf3.....ff21900>, name = "MYNAME"]
> rcvd [CHAP Challenge id=0x7 , name = "HISNAME"]
> sent [CHAP Response id=0x7 , name = "MYNAME"]
> rcvd [CHAP Challenge id=0x8 <1420....31b4>, name = "HISNAME"]
> sent [CHAP Response id=0x8 , name = "MYNAME"]
> rcvd [CHAP Challenge id=0x9 <40321a9....68b6>, name = "HISNAME"]
> sent [CHAP Response id=0x9 , name = "MYNAME"]
> rcvd [LCP TermReq id=0x4 "O\377777777171l\000<\37777777715t
> \000\000\002\37777777716"]
> LCP terminated by peer (OM-O1l^@ > sent [LCP TermAck id=0x4]
> rcvd [LCP TermReq id=0x5 "O\377777777171l\000<\37777777715t
> \000\000\002\37777777716"]
> sent [LCP TermAck id=0x5]
> Connection terminated.
> [...]
>
> Does anyone have any idea of what is happening?
>
> Thanks,
> Giuseppe