Using PPP Options in Files and on the Command Line
Solaris PPP 4.0 contains a large set of options, which you use to
define your PPP configuration. You use these options in the PPP configuration files, or on
the command line, or by using a combination of files and command-line options. This
section contains detailed information about the use of PPP options in configuration files and
as arguments to PPP commands.
Where to Define PPP Options
Solaris PPP 4.0 configuration is very flexible.You can define PPP options in the following
places:
The next table lists the PPP configuration files and commands.
Table 22-1 Summary of PPP Configuration Files and Commands
File or Command |
Definition |
For
Information |
|---|
/etc/ppp/options |
A file that contains characteristics that apply by default to all PPP links on
the system, for example, whether the machine requires peers to authenticate themselves. If this
file is absent, nonroot users are prohibited from using PPP. |
/etc/ppp/options Configuration File |
/etc/ppp/options.ttyname |
A file that describes the characteristics
of all communications over the serial port ttyname. |
/etc/ppp/options.ttyname Configuration File |
/etc/ppp/peers |
Directory that usually contains information about peers
with which a dial-out machine connects. Files in this directory are used with the
call option of the pppd command. |
Specifying Information for Communicating With the Dial-in Server |
/etc/ppp/peers/peer-name |
A file that contains characteristics of the remote
peer peer-name. Typical characteristics include the remote peer's phone number and chat script
for negotiating the link with the peer. |
/etc/ppp/peers/peer-name File |
/etc/ppp/pap-secrets |
A file that contains the necessary security credentials
for Password Authentication Protocol (PAP) authentication. |
/etc/ppp/pap-secrets File |
/etc/ppp/chap-secrets |
A file that contains the necessary security credentials for
Challenge-Handshake Authentication Protocol (CHAP) authentication. |
/etc/ppp/chap-secrets File |
~/.ppprc |
File in the home directory of a PPP user,
most often used with dial-in servers. This file contains specific information about each user's
configuration. |
Configuring $HOME/.ppprc on a Dial-in Server |
pppd options |
Command and options for initiating a PPP link and describing its characteristics. |
How PPP Options Are Processed |
Refer to the pppd(1M) man page for details on the PPP files. pppd
(1M) also includes comprehensive descriptions of all options that are available to the pppd command.
Sample templates for all the PPP configuration files are available in /etc/ppp.
How PPP Options Are Processed
The pppd daemon parses the following:
All Solaris PPP 4.0 operations are handled by the pppd daemon, which starts when a user runs the pppd command. When a user calls a remote peer, the following occurs:
pppd scans the command line to determine the device in use. The daemon does not yet interpret any options that are encountered.
pppd tries to discover the serial device to use by using these criteria:
If a serial device is specified on the command line, or a previously processed configuration file, pppd uses the name of that device.
If no serial device is named, then pppd searches for the notty, pty, or socket option on the command line. If one of these options is specified, pppd assumes that no device name exists.
Otherwise, if pppd discovers that standard input is attached to a tty, then the name of the tty is used.
If pppd still cannot find a serial device, pppd terminates the connection and issues an error.
pppd then checks for the existence of the /etc/ppp/options.ttyname file. If the file is found, pppd parses the file.
pppd processes any options on the command line.
pppd negotiates the Link Control Protocol (LCP) to set up the link.
(Optional) If authentication is required, pppd reads /etc/ppp/pap-secrets or /etc/ppp/chap-secrets to authenticate the opposite peer.
The file /etc/ppp/peers/peer-name is read when the pppd daemon encounters the option call peer-name
on the command line or in the other configuration files.
How PPP Configuration File Privileges Work
Solaris PPP 4.0 configuration includes the concept of privileges. Privileges determine the precedence of
configuration options, particularly when the same option is invoked in more than one place. An
option that is invoked from a privileged source takes precedence over the same option
that is invoked from a nonprivileged source.
User Privileges
The only privileged user is superuser (root), with the UID of zero. All other
users are not privileged.
File Privileges
The following configuration files are privileged regardless of their ownership:
/etc/ppp/options
/etc/ppp/options.ttyname
/etc/ppp/peers/peer-name
The file $HOME/.ppprc is owned by the user. Options that are read from
$HOME/.ppprc and from the command line are privileged only if the user who is
invoking pppd is root.
Arguments that follow the file option are privileged.
Effects of Option Privileges
Some options require the invoking user or source to be privileged in order to
work. Options that are invoked on the command line are assigned the privileges of
the user who is running the pppd command. These options are not privileged unless the
user who is invoking pppd is root.
Option |
Status |
Explanation |
|---|
domain |
Privileged |
Requires privileges for use. |
linkname |
Privileged |
Requires privileges for
use. |
noauth |
Privileged |
Requires privileges for use. |
nopam |
Privileged |
Requires privileges for use. |
pam |
Privileged |
Requires privileges for use. |
plugin |
Privileged |
Requires privileges for
use. |
privgroup |
Privileged |
Requires privileges for use. |
allow-ip addresses |
Privileged |
Requires privileges for use. |
name hostname |
Privileged |
Requires privileges for use. |
plink |
Privileged |
Requires
privileges for use. |
noplink |
Privileged |
Requires privileges for use. |
plumbed |
Privileged |
Requires privileges for use. |
proxyarp |
Becomes privileged if noproxyarp
has been specified |
Cannot be overridden by an unprivileged use. |
defaultroute |
Privileged if nodefaultroute is set
in a privileged file or by a privileged user |
Cannot be overridden by an
unprivileged user. |
disconnect |
Privileged if set in a privileged file or by a privileged user |
Cannot be
overridden by an unprivileged user. |
bsdcomp |
Privileged if set in a privileged file or by a
privileged user |
The nonprivileged user cannot specify a code size that is larger than the
privileged user has specified. |
deflate |
Privileged if set in a privileged file or by a
privileged user |
The nonprivileged user cannot specify a code size that is larger than the
privileged user has specified. |
connect |
Privileged if set in a privileged file or by a
privileged user |
Cannot be overridden by an nonprivileged user. |
init |
Privileged if set in a privileged file
or by a privileged user |
Cannot be overridden by an nonprivileged user. |
pty |
Privileged if set
in a privileged file or by a privileged user |
Cannot be overridden by an
nonprivileged user. |
welcome |
Privileged if set in a privileged file or by a privileged user |
Cannot be
overridden by an nonprivileged user. |
ttyname |
Privileged if set in a privileged file Not privileged if set
in a nonprivileged file |
Opened with root permissions regardless of who invokes pppd. Opened with the
privileges of the user who invokes pppd. |
/etc/ppp/options Configuration File
You use the /etc/ppp/options file to define global options for all PPP communications on
the local machine. /etc/ppp/options is a privileged file. /etc/ppp/options should be owned by
root, although pppd does not enforce this rule. Options that you define in /etc/ppp/options
have precedence over definitions of the same options in all other files and the command
line.
Typical options that you might use in /etc/ppp/options include the following:
Note - The Solaris PPP 4.0 software does not include a default /etc/ppp/options file. pppd
does not require the /etc/ppp/options file to work. If a machine does not
have an /etc/ppp/options file, only root can run pppd on that machine.
You must create /etc/ppp/options by using a text editor, as shown in How to Define Communications Over the Serial Line. If
a machine does not require global options, you can create an empty /etc/ppp/options
file. Then, both root and regular users can run pppd on the local machine.
/etc/ppp/options.tmpl Template
The /etc/ppp/options.tmpl contains helpful comments about the /etc/ppp/options file plus three common options for
the global /etc/ppp/options file.
lock
nodefaultroute
noproxyarp
Option |
Definition |
|---|
lock |
Enables UUCP-style file locking |
nodefaultroute |
Specifies that no default route is defined |
noproxyarp |
Disallows proxyarp |
To use /etc/ppp/options.tmpl as the global options file, rename /etc/ppp/options.tmpl to /etc/ppp/options. Then,
modify the file contents as needed by your site.
Where to Find Examples of the /etc/ppp/options Files
To find examples of the /etc/ppp/options file, refer to the following:
/etc/ppp/options.ttyname Configuration File
You can configure the characteristics of communications on the serial line in the /etc/ppp/options.ttyname
file. /etc/ppp/options.ttyname is a privileged file that is read by pppd
after parsing any existing /etc/ppp/options and existing $HOME/.ppprc files. Otherwise, pppd reads /etc/ppp/options.ttyname
after parsing /etc/ppp/options.
ttyname is used for both dial-up and leased-line links. ttyname represents a particular serial port
on a machine, such as cua/a or cua/b, where a modem or ISDN TA
might be attached.
When naming the /etc/ppp/options.ttyname file, replace the slash (/) in the device name with
a dot (.). For example, the options file for device cua/b should be named /etc/ppp/options.cua.b.
Note - Solaris PPP 4.0 does not require an /etc/ppp/options.ttyname file to work correctly. Your
server might have only one serial line for PPP. Furthermore, the server requires
few options. In this instance, you can specify any required options in another configuration file
or on the command line.
Using /etc/ppp/options.ttyname on a Dial-in Server
For a dial-up link, you might choose to create individual /etc/ppp/options.ttyname files for
every serial port on a dial-in server with a modem attached. Typical options include the
following:
IP address required by the dial-in server
Set this option if you require incoming callers on serial port ttyname to use a particular IP address. Your address space might have a limited number of IP addresses that are available for PPP in comparison to the number of potential callers. In this situation, consider assigning an IP address to each serial interface that is used for PPP on the dial-in server. This assignment implements dynamic addressing for PPP.
asyncmap map-value
The asyncmap option maps control characters that cannot be received over the serial line by the particular modem or ISDN TA. When the xonxoff option is used, pppd automatically sets an asyncmap of 0xa0000.
map-value states, in hexadecimal format, the control characters that are problematic.
init "chat -U -f /etc/ppp/mychat"
The init option tells the modem to initialize communications over the serial line by using the information in the chat -U command. The modem uses the chat string in the file /etc/ppp/mychat.
Security parameters that are listed in the pppd(1m) man page
Using /etc/ppp/options.ttyname on a Dial-out Machine
For a dial-out system, you can create an /etc/ppp/options.ttyname file for the serial port
that is connected to the modem, or choose not to use /etc/ppp/options.ttyname.
Note - Solaris PPP 4.0 does not require an /etc/ppp/options.ttyname file to work correctly. A
dial-out machine might have only one serial line for PPP. Furthermore, the
dial-out machine might require few options. You can specify any required options in
another configuration file or on the command line.
options.ttya.tmpl Template File
The /etc/ppp/options.ttya.tmpl file contains helpful comments about the /etc/ppp/options.tty-name file. The template contains three
common options for the /etc/ppp/options.tty-name file.
38400
asyncmap 0xa0000
:192.168.1.1
Option |
Definition |
|---|
38400 |
Use this baud rate for port ttya. |
asyncmap 0xa0000 |
Assign the asyncmap
value of 0xa0000 so that the local machine can communicate with broken peers. |
:192.168.1.1 |
Assign the
IP address 192.168.1.1 to all peers that are calling in over the link. |
To use /etc/ppp/options.ttya.tmpl at your site, rename /etc/ppp/options.tmpl to /etc/ppp/options.ttya-name. Replace ttya-name
with the name of the serial port with the modem. Then modify the file
contents as needed by your site.
Where to Find Examples of the /etc/ppp/options.ttyname Files
To find examples of the /etc/ppp/options.ttyname files, refer to the following:
