9: Device Ports
EMG™ Edge Management Gateway User Guide
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will be established using either negotiated IP addresses or specific IP addresses (determined
by the
Negotiate IP Address
setting). The PPP connection will stay active until no IP traffic is
sent for
Modem Timeout
seconds. Once the timeout has expired, the PPP connection will be
terminated and will not be reestablished for at least
Restart Delay
seconds.
Dial-back & Dial-on-demand
A modem is configured to be in two modes: answering incoming calls to initiate a dial-back, and
automatically dialing out to establish a PPP connection when IP traffic destined for a remote
network needs to be sent. When either event occurs (an incoming call or IP traffic destined for the
remote network), the other mode will be disabled.
For Dial-back, the user will be authenticated via PAP or CHAP (determined by the
Authentication
setting for the modem). For PAP, the Local/Remote User list will be used to
authenticate the login and password sent by the PPP peer, and the site list will be searched for
a site that (a) the
Login/CHAP Host
matches the name that was authenticated, (b)
Authentication
is set to PAP, and (c) the
Port
is set to
None
or matches the port the modem
is on. For CHAP, the site list will be searched for a site that (a) the
Login/CHAP Host
and
CHAP Secret
match the name and secret sent in the CHAP Challenge response by the PPP
peer, (b)
Authentication
is set to CHAP, and (c) the
Port
is set to
None
or matches the port
the modem is on. If the remote peer requests PAP or CHAP authentication from the EMG unit,
the
Remote/Dial-out Login
and
Remote/Dial-out Password
configured for the modem (not
the site) will be provided as authentication tokens.
If a matching site is found, its
Dial-back Number
,
Allow Dial-back
,
Dial-back Delay
,
Dial-
out Login
,
Dial-out Password
,
Negotiate IP Address
,
NAT
, and
Modem Timeout
parameters will be used for the rest of the dial-back connection instead of the parameters
configured for the modem. Once the remote server is authenticated, if
Allow Dial-back
is
enabled for the site and a
Dial-back Number
is defined, the EMG will hang up and wait
Dial-
back Delay
seconds before initiating the dial-back. The EMG unit will dial, and if the remote
peer requests PAP or CHAP authentication, provide the
Dial-out Login
and
Dial-out
Password
as authentication tokens. Once authenticated, a PPP session will be established
using either negotiated IP addresses or specific IP addresses (determined by the
Negotiate
IP Address
setting).
For Dial-on-Demand, the EMG searches the site list for all sites that (a) have a
Dial-out
Number
defined, (b) have a
Static Route IP Address
,
Static Route Subnet Mask
and
Static
Route Gateway
defined, and (c) the
Port
matches the port the modem is on. A dial-on-
demand connection will be started for each, waiting for IP traffic destined for a remote
network.
When IP traffic needs to be sent, the EMG unit dials the appropriate
Dial-out Number
for the
site, and if the remote peer requests PAP or CHAP authentication, provides the
Dial-out
Login
and
Dial-out Password
as authentication tokens. Once authenticated, a PPP session
will be established using either negotiated IP addresses or specific IP addresses (determined
by the
Negotiate IP Address
setting). The PPP connection will stay active until no IP traffic is
sent for
Modem Timeout
seconds. Once the timeout has expired, the PPP connection will be
terminated and will not be reestablished for at least
Restart Delay
seconds.
CBCP Server and CBCP Client
Callback Control Protocol (CBCP) is a PPP option that negotiates the use of callback where the
server, after authenticating the client, terminates the connection and calls the client back at a
phone number that is determined by the CBCP handshake. For more information on CBCP, see
http://technet.microsoft.com/en-us/library/cc957979.aspx
. CBCP is used primarily by Microsoft
PPP peers. CBCP supports two options for determining the number to dial on callback: the client
can specify a user-defined number for the server to dial on callback, or the client can request the