.\" Copyright (C) 1997, 2001 by Joerg Wunsch, Dresden
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.Dd December 30, 2001
.Dt SPPPCONTROL 8
.Os
.Sh NAME
.Nm spppcontrol
.Nd display or set parameters for an sppp interface
.Sh SYNOPSIS
.Nm
.Op Fl v
.Ar ifname
.Op Ar parameter Ns Op Li = Ns Ar value
.Op Ar ...
.Sh DESCRIPTION
The
.Xr sppp 4
driver might require a number of additional arguments or optional
parameters besides the settings that can be adjusted with
.Xr ifconfig 8 .
These are things like authentication protocol parameters, but also
other tunable configuration variables.
The
.Nm
utility can be used to display the current settings, or adjust these
parameters as required.
.Pp
For whatever intent
.Nm
is being called, at least the parameter
.Ar ifname
needs to be specified, naming the interface for which the settings
are to be performed or displayed.
Use
.Xr ifconfig 8 ,
or
.Xr netstat 1
to see which interfaces are available.
.Pp
If no other parameter is given,
.Nm
will just list the current settings for
.Ar ifname
and exit.
The reported settings include the current PPP phase the
interface is in, which can be one of the names
.Em dead ,
.Em establish ,
.Em authenticate ,
.Em network ,
or
.Em terminate .
If an authentication protocol is configured for the interface, the
name of the protocol to be used, as well as the system name to be used
or expected will be displayed, plus any possible options to the
authentication protocol if applicable.
Note that the authentication
secrets (sometimes also called
.Em keys )
are not being returned by the underlying system call, and are thus not
displayed.
.Pp
If any additional parameter is supplied, superuser privileges are
required, and the command works in the
.Dq set
mode.
This is normally done quietly, unless the option
.Fl v
is also enabled, which will cause a final printout of the settings as
described above once all other actions have been taken.
Use of this
mode will be rejected if the interface is currently in any other phase
than
.Em dead .
Note that you can force an interface into
.Em dead
phase by calling
.Xr ifconfig 8
with the parameter
.Cm down .
.Pp
The currently supported parameters include:
.Bl -tag -offset indent -width indent
.It Va authproto Ns Li = Ns Ar protoname
Set both, his and my authentication protocol to
.Ar protoname .
The protocol name can be one of
.Dq Li chap ,
.Dq Li pap ,
or
.Dq Li none .
In the latter case, the use of an authentication protocol will be
turned off for the named interface.
This has the side-effect of
clearing the other authentication-related parameters for this
interface as well (i.e., system name and authentication secret will
be forgotten).
.It Va myauthproto Ns Li = Ns Ar protoname
Same as above, but only for my end of the link.
I.e., this is the
protocol when remote is authenticator, and I am the peer required to
authenticate.
.It Va hisauthproto Ns Li = Ns Ar protoname
Same as above, but only for his end of the link.
.It Va myauthname Ns Li = Ns Ar name
Set my system name for the authentication protocol.
.It Va hisauthname Ns Li = Ns Ar name
Set his system name for the authentication protocol.
For CHAP, this
will only be used as a hint, causing a warning message if remote did
supply a different name.
For PAP, it is the name remote must use to
authenticate himself (in connection with his secret).
.It Va myauthsecret Ns Li = Ns Ar secret
Set my secret (key, password) for use in the authentication phase.
For CHAP, this will be used to compute the response hash value, based
on remote's challenge.
For PAP, it will be transmitted as plain text
together with the system name.
Do not forget to quote the secrets from
the shell if they contain shell metacharacters (or white space).
.It Va myauthkey Ns Li = Ns Ar secret
Same as above.
.It Va hisauthsecret Ns Li = Ns Ar secret
Same as above, to be used if we are an authenticator and the remote peer
needs to authenticate.
.It Va hisauthkey Ns Li = Ns Va secret
Same as above.
.It Va callin
Require remote to authenticate himself only when he is calling in, but
not when we are caller.
This is required for some peers that do not
implement the authentication protocols symmetrically (like Ascend
routers, for example).
.It Va always
The opposite of
.Va callin .
Require remote to always authenticate, regardless of which side is
placing the call.
This is the default, and will not be explicitly
displayed in the
.Dq list
mode.
.It Va norechallenge
Only meaningful with CHAP.
Do not re-challenge peer once the initial
CHAP handshake was successful.
Used to work around broken peer
implementations that cannot grok being re-challenged once the
connection is up.
.It Ar rechallenge
With CHAP, send re-challenges at random intervals while the connection
is in network phase.
(The intervals are currently in the range of 300
through approximately 800 seconds.)
This is the default, and will not
be explicitly displayed in the
.Dq list
mode.
.It Va lcp-timeout Ns Li = Ns Ar timeout-value
Allows to change the value of the LCP restart timer.
Values are
specified in milliseconds.
The value must be between 10 and 20000 ms,
defaulting to 3000 ms.
.It Va enable-vj
Enable negotiation of Van Jacobsen header compression.
(Enabled by default.)
.It Va disable-vj
Disable negotiation of Van Jacobsen header compression.
.It Va enable-ipv6
Enable negotiation of the IPv6 network control protocol.
(Enabled by default if the kernel has IPv6 enabled.)
.It Va disable-ipv6
Disable negotiation of the IPv6 network control protocol.
Since every
IPv4 interface in an IPv6-enabled kernel automatically gets an IPv6
address assigned, this option provides for a way to administratively
prevent the link from attempting to negotiate IPv6.
Note that
initialization of an IPv6 interface causes a multicast packet to be
sent, which can cause unwanted traffic costs (for dial-on-demand
interfaces).
.El
.Sh EXAMPLES
.Bd -literal
# spppcontrol bppp0
bppp0:	phase=dead
	myauthproto=chap myauthname="uriah"
	hisauthproto=chap hisauthname="ifb-gw" norechallenge
	lcp-timeout=3000
	enable-vj
	enable-ipv6
.Ed
.Pp
Display the settings for
.Li bppp0 .
The interface is currently in
.Em dead
phase, i.e., the LCP layer is down, and no traffic is possible.
Both
ends of the connection use the CHAP protocol, my end tells remote the
system name
.Dq Li uriah ,
and remote is expected to authenticate by the name
.Dq Li ifb-gw .
Once the initial CHAP handshake was successful, no further CHAP
challenges will be transmitted.
There are supposedly some known CHAP
secrets for both ends of the link which are not being shown.
.Bd -literal
# spppcontrol bppp0 \e
	authproto=chap \e
	myauthname=uriah myauthsecret='some secret' \e
	hisauthname=ifb-gw hisauthsecret='another' \e
	norechallenge
.Ed
.Pp
A possible call to
.Nm
that could have been used to bring the interface into the state shown
by the previous example.
.Sh SEE ALSO
.Xr netstat 1 ,
.Xr sppp 4 ,
.Xr ifconfig 8
.Rs
.%A B. Lloyd
.%A W. Simpson
.%T "PPP Authentication Protocols"
.%O RFC 1334
.Re
.Rs
.%A W. Simpson, Editor
.%T "The Point-to-Point Protocol (PPP)"
.%O RFC 1661
.Re
.Rs
.%A W. Simpson
.%T "PPP Challenge Handshake Authentication Protocol (CHAP)"
.%O RFC 1994
.Re
.Sh HISTORY
The
.Nm
utility appeared in
.Fx 3.0 .
.Sh AUTHORS
The program was written by
.An J\(:org Wunsch ,
Dresden.