Subject: How handle an unacceptable CfgNak??

From: "John R. Martz" <[email-masked]>
Date: Fri, 10 Sep 1999 17:31:53 -0400

What's the correct response if a peer sends a CfgNak to prompt for an option that is NOT acceptable
for negotiation?

Today I was looking through a trace that came in from a customer and saw a situation like this. My
implementation is receiving a Configure-Nak containing MRRU (LCP option 0x11) from the other peer.
Apparently the other peer desires to use MP in the worst way, but it's just not going to happen.

Is there a way to actively tell a peer that is sending you prompting CfgNak's to "shut up already"?
All I could think of was Configure-Reject. However, the description of Configure-Reject in RFC 1661
only allows sending Configure-Reject in response to an option in a Configure-Request, not
Configure-Nak.

Thanks,
-john martz ([email-masked])
IBM AS/400 TCP/IP PPP (and stuff)

---

From: Vernon Schryver <[email-masked]>
Date: Fri, 10 Sep 1999 15:58:18 -0600 (MDT)

> From: "John R. Martz" <[email-masked]>

> Is there a way to actively tell a peer that is sending you prompting CfgNak's to "shut up already"?

No.  Your implementation should just (and can only) be patient.

> only allows sending Configure-Reject in response to an option in a Configure-Request, not

That's right.  You cannot send a Configure-Reject in response to a
Configure-Nak.

James Carlson's book, "PPP Design and Debugging" addresses this and similar
issues.   I know this point has been often mentioned in this mailinglist,
but Jim's book is shorter and more readable.  It also has an index that
points to page 34, which says

  ... Of course, this rarely works to prod the Configure-Request sender
  to include the option. ...

Vernon Schryver    [email-masked]