Cbcp; Ncp; Starting Ppp - Lantronix SCS Reference Manual

PPP
On incoming connections, the port's CHAP or PAP configuration will be used to determine the
authentication required for the connection. For example, if a remote node was logged into port 2 on the SCS
and port 2 was configured to use PAP to authenticate remote hosts, the remote node would be prompted to
authenticate itself.
Outgoing connections use the site's CHAP or PAP configuration. For example, if site irvine, which has
CHAP enabled, initiated an outgoing connection to a remote router, and the remote site required the SCS to
authenticate itself using CHAP, the SCS would offer its username and password to the remote site.
Use caution with CHAP/PAP authentication because configuring both a local and a remote password on the
same site could compromise security. If a site with both local and remote passwords defined receives an
incoming call, during the LCP negotiation process the site will say that it is willing to transmit both
passwords. The passwords will not be automatically transmitted, but the site will let the user know that it is
willing to do so if required. If the user requires the SCS to authenticate itself, the SCS will transmit the
remote password over the link, thereby give the user a password to access the server.
For a complete description of authentication, refer to Chapter 11, Security.
Note:

7.1.5 CBCP

The SCS supports the Microsoft Callback Control Protocol (CBCP) for dial-in PPP clients that request it.
In conjunction with the CBCP, you can configure the SCS to allow the PPP client to choose a dialback
telephone number to reverse phone charges.
For more information, see Dialback Using CBCP on page 11-7.

7.2 NCP

Network Control Protocols (NCPs) govern use of a specific network protocol over the PPP link. On the SCS,
PPP uses the IP protocol. PPP uses the IP Control Protocol (IPCP) to negotiate the use of IP over a link.
IPCP allows for dynamic address assignment and Van Jacobson TCP header compression.
IP over PPP is described in RFC 1332. Van Jacobson TCP compression is
Note:
covered in RFC 1144.
If, during the negotiation process, the SCS receives a request for more IP compression slots than are
configured on the site (using the Define Site IP Slots command), the SCS will NAK (negative
acknowledge), and request the number of slots configured on the site.

7.3 Starting PPP

PPP can be started in a number of ways. For a detailed discussion of the PPP startup sequence, see Starting
PPP/Slip for Incoming Connections on page 4-11 and Using Sites for Outgoing Connections on page 4-6.
7-3
NCP