PPPCONFIG(8) BSD System Manager's Manual PPPCONFIG(8)
NAME
pppconfig - configure Point-to-Point Protocol parameters
SYNOPSIS
pppconfig interface [parameters]
DESCRIPTION
Pppconfig is used to examine and/or set parameters of a point-to-point
protocol link. When called without parameters, pppconfig will print up
to three sets of parameters: the initial parameters as used before nego-
tiating the PPP options, the current negotiated parameters if the link is
active, and the non-negotiated parameters which do not require the nego-
tiation between the local and remote side.
Pppconfig can be used to change the initial and non-negotiated parameters
at any time (superuser permissions required); however it is not possible
to change the negotiated parameters ``on the fly'' - the connection
should be terminated and reestablished for the new parameters to take ef-
fect. If the link is not active the negotiated parameters assume the
initial values.
The interface parameter is a string of the form ``name unit'', for exam-
ple, ``rn0''.
The following parameters may be set with pppconfig:
cmap charmap Specify which control characters should be avoided on asyn-
chronous lines in case the equipment uses some of them for
flow control or link control or inserts characters for time
fill. The charmap may be specified as a 32-bit hexadecimal
or octal number (if it starts with 0x or 0 respectively),
in which case the least significant bit corresponds to the
null character and the most significant bit to the charac-
ter with code 037 (US). Alternatively, it may be specified
as a string of letters corresponding the control charac-
ters, for example ``@QS'' will represent mask with bits 0,
17 and 19 set. The default all-zero mask will allow trans-
mission of all control characters.
mru size Specify the maximal packet size the local side is willing
to receive. This option can be useful on packet-switching
links to prevent link-level packet fragmentation or in case
of problems with hardware flow control. The default value
for mru is 1500 bytes.
pfc Enable protocol field compression. This option eliminates
an extra byte in PPP packet header, which can be useful on
slow links but can cause computing overhead on fast syn-
chronous links. This option is default on asynchronous
lines.
-pfc Disable protocol field compression. This option is default
on synchronous lines.
acfc Enable address and control fields compression. This option
reduces the size of a PPP packet header by two bytes, which
can be useful on slow links but can cause computing over-
head on fast synchronous links. This option is default on
asynchronous lines.
-acfc Disable address and control fields compression. This op-
tion is default on synchronous lines.
tcpc Enable Van Jacobson's TCP header compression. This option
enables compression of TCP headers by eliminating redundant
information in the headers of consecutive TCP packets, re-
ducing the protocol overhead by up to 100 bytes per packet,
which may be really critical to the performance of interac-
tive telnet or rlogin sessions. However, VJ TCP compres-
sion requires the system to keep state information about
every TCP session on both ends (up to 16 simultaneous ses-
sions) and is not really useful on fast links connecting
large networks. TCP compression does not affect UDP and
ICMP packets. This option is default on asynchronous
lines.
-tcpc Disable Van Jacobson's TCP header compression. This option
is default on synchronous lines.
ftel Enable high-priority queueing of ``interactive'' TCP pack-
ets (with source or destination ports assigned to services
like telnet or control connection of ftp(1)), effectively
giving them precedence over all other IP packets. This can
reduce response time on links with mixed file transfer and
interactive traffic. This function is a temporary and lim-
ited substitute for the still unsupported IP low delay TOS
(type of service). This option is default on asynchronous
lines.
-ftel Disable the ``fast telnet'' option. This is default on
synchronous lines.
trace Enable printing of trace information for PPP control pack-
ets and protocol finite state machine transitions. This
option is effective only if the kernel is configured to in-
clude the PPP trace printing code. The default value for
this option is defined by the kernel configuration.
-trace Disable printing of trace information for PPP control pack-
ets and protocol finite state machine transitions.
idletime n Set the idle timer to drop the connection if no outgoing
data packets were processed during the last n seconds (the
maximal time is 32767 seconds).
-idletime Disable the idle timer. This option is default.
maxconf n Set the limit on attempts to negotiate PPP control protocol
options to n. After the specified number of unsuccessful
attempts the connection will be dropped. This option is
useful on dial-up links to force the connection to drop
when there is a malfunction on the remote side. The de-
fault value on asynchronous lines is 10. The maximal value
of maxconf is 255.
-maxconf Allow unlimited attempts to negotiate PPP options. This
option should be used on dedicated lines and is default on
synchronous lines.
maxterm n Set the limit on attempts to terminate the link gracefully
to n. The default is 3 attempts before unilaterally drop-
ping the connection. The maximal value of maxterm is 255.
timeout n Specify the interval between attempts to config-
ure/terminate the link in tenths of a second. The default
value is 30 (3 seconds), the maximal value is 255 (25.5
seconds).
Only the super-user may modify the configuration of a network interface.
If the interface supports more than one link-level protocol (for example,
a synchronous link), the PPP protocol should be selected before configur-
ing the PPP parameters (see ppp(4) and ifconfig(8)). The default values
will be loaded when the link-level protocol is switched to PPP from some
other protocol.
DIAGNOSTICS
Messages indicating the specified interface does not exist, the requested
address is unknown, or the user is not privileged and tried to alter an
interface's PPP configuration.
SEE ALSO
ifconfig(8), ppp(4), pppattach(8), ppp(8), rn(4), rh(4), appp(4)
W. Simpson, The Point-to-Point Protocol (PPP) for the Transmission of
Multi-protocol Datagrams over Point-to-Point Links, RFC 1331, May 1992.
G. McGregor, The PPP Internet Protocol Control Protocol (IPCP), RFC 1332,
May 1992.
HISTORY
The pppconfig command is currently under development.
BSDI BSD/386 March 27, 1993 3