[nsp] NoCallback - cisco router - microsoft host

From: odusseus (odusseus@voila.fr)
Date: Thu Jul 18 2002 - 06:21:35 EDT


Hi all,

I am working with a cisco router 1750 Software (C1700-SY-M), Version 12.1(2)T.
The remote host is a PC windows 2000.

Although the router is configured as a call back server, concerning one host only, I don't want to use any call back feature. The
router's interface is configured this way:
-----
!
interface BRI0
 ip unnumbered FastEthernet0
 no ip redirects
 no ip unreachables
 encapsulation ppp
 no ip mroute-cache
 no keepalive
 dialer callback-secure
 dialer idle-timeout 900
 dialer enable-timeout 10
 dialer load-threshold 1 either
 dialer-group 1
 isdn switch-type basic-net3
 peer default ip address pool poolpr
 no cdp enable
 ppp callback accept
 ppp authentication chap
 ppp multilink
!
-----

So I configured the remote host not to allow any call back.

>From the router I disabled the callback feature for the following user this way:

---
username <name> password <password>
---

In comparison, users requiring call back are configured this way from the router: --- username <name> callback-dialstring <phone_number> password <password> ---

Then during ppp negotiations, both sides agreed on this following parameter: without call-back: --- 21w5d: BR0:1 LCP: I CONFACK [ACKsent] id 132 len 23 21w5d: BR0:1 LCP: AuthProto CHAP (0x0305C22305) 21w5d: BR0:1 LCP: MagicNumber 0x11073E82 (0x050611073E82) 21w5d: BR0:1 LCP: EndpointDisc 1 Local (0x1308016D74657374) ---

Then the authentication starts and succeeds.

Just after the authentication process, the next process starting is MCB.

MCB seems to be related with Microsoft Callback Control Protocol.

I don't really understand why MCB is starting. As a result, MCB sees that concerning the user <name> the call back is not allowed, the router asks a kind of confirmation to the remote host, the remote host answer that it does not use any call back policy. So receiving such answer, the MCB is: shutdown, and following this event, the connection is closed: --- 21w5d: BR0:1 MCB: Start 21w5d: BR0:1 MCB: Callback not authorized for this user cisco 21w5d: BR0:1 MCB: Newstate 0-INIT -> 2-WAIT_RESPONSE 21w5d: BRI0:1 PPP: O MCB Request(1) id 217 len 6 21w5d: BRI0:1 MCB: O 1 D9 0 6 1 2 21w5d: BR0:1 MCB: O Request Id 217 Callback Type None

# Check the CallBack Control Policy 21w5d: BR0:1 PPP: Phase is CBCP [0 sess, 0 load] 21w5d: BR0:1: CHAP_RRESPONSE (0x80E64384) id 138 (0s.) busy/0 done in 0 s. 0/0/1

# Remote host answer that no Call BacK can be used. 21w5d: BRI0:1 PPP: I MCB Response(2) id 217 len 6 21w5d: BRI0:1 MCB: I 2 D9 0 6 1 2 21w5d: BR0:1 MCB: Received response 21w5d: BR0:1 MCB: Response CBK-None 1 2

# The router agreed, no call back will be used 21w5d: BRI0:1 PPP: O MCB Ack(3) id 218 len 6 21w5d: BRI0:1 MCB: O 3 DA 0 6 1 2 21w5d: BR0:1 MCB: O Ack Id 218 Callback Type None

# Since the callback feature cannot be used, the connection is shuted down by the router. 21w5d: BR0:1 MCB: No Callback negotiated; Exit 21w5d: BR0:1 MCB: Shutdown 21w5d: BR0:1 MCB: Flush Jul 18 09:32:52: %LINK-3-UPDOWN: Interface BRI0:1, changed state to down 21w5d: BR0:1 PPP: Phase is TERMINATING [0 sess, 0 load] 21w5d: BR0:1 LCP: State is Closed 21w5d: BR0:1 PPP: Phase is DOWN [0 sess, 0 load] ---

Can someone tell me why MCB is starting?

Thank you.

Regards,

Christophe ------------------------------------------

Faites un voeu et puis Voila ! www.voila.fr



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