The following procedure sets up applications, such as tip and uucp, to access a modem:
1. Use the rtelnet utility to create a special file that references a Remote Annex port. Using rtelnet allows setting up the
application as if /dev/modem is directly connected. The following example ties /dev/modem to port 13 onannex02.
# rtelnet –mr annex02 13 /dev/modem
In the previous example, the –m argument instructs the
Remote Annex to drop momentarily the network connection to the Remote Annex port when the pseudo device is closed; it also causes the modem to hang up when the application exits. The –r argument directs rtelnet to remove thedevice nameif it already exists; without –r, rtelnet exits with an error message if thedevice namealready exists.
2. Add rtelnet to /etc/rc (or the appropriate file) so that the special file is created when the host boots.
3. Configure the application to use the special file created by rtelnet to access the modem. See the appropriate system documentation for the required steps.
If the system uses a name server to translate host names to Internet addresses and you use the Remote Annex’s name in the rtelnet command, make sure that the Remote Annex is listed in the name server database and that the name server is started before the rtelnet command.
To access a modem attached to an adaptive or auto_adapt port:
1. Use the rtelnet utility to create a special file that references a Remote Annex port. Using rtelnet allows setting up the
application as if /dev/modem is directly connected. The following example ties
/dev/modem to port 13 on the Remote Annex namedannex02.
# rtelnet –fmr annex02 13 /dev/modem
In this example, the –f argument instructs the Remote Annex to release the port when the device is no longer using it, thus releasing the port for use as a CLI. The –m argument instructs the
Remote Annex to drop momentarily the network connection to the Remote Annex port when the pseudo device is closed; it also causes the modem to hang up when the application exits. The –r argument
2. Add rtelnet to /etc/rc (or the appropriate file) so that the special file is created when the system boots.
3. Configure the application to use the special file created by rtelnet to access the modem. See the appropriate system documentation for the required steps.
If the system uses a name server to translate host names to Internet addresses and you use the Remote Annex’s name in the rtelnet command, make sure that the Remote Annex is listed in the name server database and that the name server is started before the rtelnet command.
getty
The following procedure sets up an application, such as getty, to access a modem:
1. Use rtelnet to create a special file that references a Remote Annex port:
# rtelnet –mr annex02 3 /dev/modem
2. Enable a getty process that monitors the port. See the appropriate system documentation for the required steps.
For a 4.3BSD system, add a line to /etc/ttys to define thedevice nameas a getty line. For a Sun OS 4.x system, add a line to /etc/ttytab. The following example can be used with
either system:
modem “/etc/getty std.9600” ansi on
Then, signal init to read the file and start a getty for that port:
# kill –HUP 1
Add rtelnet to /etc/rc (or the appropriate file) so that the special file is created when the system boots.
Other operating systems use different formats for creating a getty process.
If the system uses a name server to translate host names to Internet addresses and you use the Remote Annex’s name in the rtelnet command, make sure that the Remote Annex is listed in the name server database and that the name server is started before the rtelnet command.
T
his chapter describes the Remote Annex’s implementation of the standardized method for transmitting datagrams from multiple protocols over serial point-to-point links. PPP provides three functions:• Asynchronous High-level Data Link Control (HDLC) to encapsulate the packets.
• Link Control Protocol (LCP) to establish the connection between peers.
• A family of Network Control Protocols (NCPs) to configure network interfaces.
PPP allows a site to use the Remote Annex as a wide area network (WAN) hub, tying distant corners of an IP network together over low cost phone lines. PPP features include:
• FCS error checking.
• Agreement by each end of the connection on a mutually acceptable set of features for that connection.
• Large Maximum Receive Unit (MRU) size -- negotiations start at 1500.
In setting up a PPP link:
• You can attach a PC to a Remote Annex serial port. Using PPP as the network interface, the PC becomes a host on the network.
For a remote PC with a PPP client that supports scripting, you can configure a port in CLI mode. Then, a user at a remote PC can dial into the Remote Annex using a modem and convert the port from a CLI to a PPP link using the CLI ppp command.
After converting the port to a PPP link, the remote PC becomes a host directly attached to the network.
• Alternatively, you can set a Remote Annex port to auto_detect or auto_adapt. When the Remote Annex detects the PPP protocol on the line attached to the port, it automatically converts the port mode to PPP and starts LCP negotiations.
• If your PPP client is expecting to connect to a server already in ppp mode, the Remote Annex port’s mode must be ppp, auto_detect, or auto_adapt.
• You can use PPP to connect two separate networks, routing data from one network to the other over the PPP link.
The Remote Annex cannot boot over a PPP link.