pptpd/pptpd.conf.5

.TH PPTPD.CONF 5 "29 December 2005"
.SH NAME
.B pptpd.conf
- PPTP VPN daemon configuration
.SH DESCRIPTION
.BR pptpd (8)
reads options from this file, usually
.IR /etc/pptpd.conf .
Most options can be overridden by the command line.  The local and
remote IP addresses for clients must come from the configuration file
or from
.BR pppd (8)
configuration files.
.SH OPTIONS
.TP
.BI "option " option-file
the name of an option file to be passed to
.BR pppd (8)
in place of the default
.IR /etc/ppp/options 
so that PPTP specific options can be given.
Equivalent to the command line
.B --option
option.

.TP
.BI "stimeout " seconds
number of seconds to wait for a PPTP packet before forking the
.BR pptpctrl (8)
program to handle the client.  The default is 10 seconds.  This is a
denial of service protection feature.
Equivalent to the command line 
.B --stimeout
option.
.TP
.B debug
turns on debugging mode, sending debugging information to 
.BR syslog (3).
Has no effect on
.BR pppd (8)
debugging.  Equivalent to the command line 
.B --debug
option.
.TP
.BI "bcrelay " internal-interface
turns on broadcast relay mode, sending all broadcasts received on the server's
internal interface to the clients.
Equivalent to the command line 
.B --bcrelay
option.

.TP
.BI "connections " n
limits the number of client connections that may be accepted.
If pptpd is allocating IP addresses (e.g. 
.BR delegate
is not used) then the number of connections is also limited by the
.BR remoteip
option.  The default is 100.

.TP
.BI "delegate"
delegates the allocation of client IP addresses to 
.BR pppd (8).
Without this option, which is the default, pptpd manages the list of
IP addresses for clients and passes the next free address to pppd.
With this option, pptpd does not pass an address, and so pppd may use
radius or chap-secrets to allocate an address.

.TP
.BI "localip " ip-specification
one or many IP addresses to be used at the local end of the
tunnelled PPP links between the server and the client.  If one address only
is given, this address is used for all clients.  Otherwise, one address
per client must be given, and if there are no free addresses then any new
clients will be refused.
.B localip
will be ignored if the
.B delegate
option is used.
.TP
.BI "remoteip " ip-specification
a list of IP addresses to assign to remote PPTP clients. Each
connected client must have a different address, so there must be
at least as many addresses as you have simultaneous clients,
and preferably some spare, since you cannot change this list
without restarting pptpd. A warning will be sent to
.BR syslog (3)
when the IP address pool is exhausted.
.B remoteip
will be ignored if the
.B delegate
option is used.
.TP
.B noipparam
by default, the original client IP address is given to
ip-up scripts using the 
.BR pppd (8) 
option
.B ipparam.
The
.B noipparam
option prevents this.
Equivalent to the command line
.B --noipparam
option.
.TP
.BI "listen " ip-address
the local interface IP address to listen on for incoming PPTP
connections (TCP port 1723). Equivalent to the command line
.B --listen
option.
.TP
.BI "pidfile " pid-file
specifies an alternate location to store the process ID file
(default /var/run/pptpd.pid).  Equivalent to the command line
.B --pidfile
option.
.TP
.BI "speed " speed
specifies a speed (in bits per second) to pass to the PPP daemon as
the interface speed for the tty/pty pair.  This is ignored by some PPP
daemons, such as Linux's
.BR pppd (8).
The default is 115200 bytes per second, which some implementations
interpret as meaning "no limit".  Equivalent to the command line
.B --speed
option.
.SH NOTES
An
.I ip-specification
above (for the
.B localip
and
.B remoteip
tags) may be a list of IP addresses (for example 192.168.0.2,192.168.0.3),
a range (for example 192.168.0.1-254 or 192.168.0-255.2) or some combination
(for example 192.168.0.2,192.168.0.5-8).  For some valid pairs might be
(depending on use of the VPN):
.P
.BI "localip " 192.168.0.1
.br
.BI "remoteip " 192.168.0.2-254
.P
or
.P
.BI "localip " 192.168.1.2-254
.br
.BI "remoteip " 192.168.0.2-254

.SH ROUTING CHECKLIST - PROXYARP
Allocate a section of your LAN addresses for use by clients.
.P
In 
.IR /etc/ppp/options.pptpd.
set the
.B proxyarp
option.
In
.IR pptpd.conf
do not set 
.B localip
option, but set
.B remoteip
to the allocated address range.
Enable kernel forwarding of packets, (e.g. using
.IR /proc/sys/net/ipv4/ip_forward
).
.P
The server will advertise the clients to the LAN using ARP, providing
it's own ethernet address.
.BR bcrelay (8)
should not be required.

.SH ROUTING CHECKLIST - FORWARDING
Allocate a subnet for the clients that is routable from your LAN, but
is not part of your LAN.
.P
In
.IR pptpd.conf
set
.B localip
to a single address or range in the allocated subnet, set
.B remoteip
to a range in the allocated subnet.
Enable kernel forwarding of packets, (e.g. using
.IR /proc/sys/net/ipv4/ip_forward
).
The LAN must have a route to the clients using the server as gateway.
.P
The server will forward the packets unchanged between the clients and the LAN.
.BR bcrelay (8)
will be required to support broadcast protocols such as NETBIOS.

.SH ROUTING CHECKLIST - MASQUERADE
Allocate a subnet for the clients that is not routable from your LAN,
and not otherwise routable from the server (e.g. 10.0.0.0/24).
.P
Set
.B localip
to a single address in the subnet (e.g. 10.0.0.1), set
.B remoteip
to a range for the rest of the subnet, (e.g. 10.0.0.2-200).
Enable kernel forwarding of packets, (e.g. using
.IR /proc/sys/net/ipv4/ip_forward
).
Enable masquerading on eth0 (e.g. 
.I
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
).
.P
The server will translate the packets between the clients and the LAN.
The clients will appear to the LAN as having the address
corresponding to the server.  The LAN need not have an explicit route
to the clients.
.BR bcrelay (8)
will be required to support broadcast protocols such as NETBIOS.

.SH FIREWALL RULES
.BR pptpd (8)
accepts control connections on TCP port 1723, and then uses GRE
(protocol 47) to exchange data packets.  Add these rules to your
.BR iptables (8)
configuration, or use them as the basis for your own rules:
.P
iptables --append INPUT --protocol 47 --jump ACCEPT 
.br
.nf
iptables --append INPUT --protocol tcp --match tcp \\
.br
         --destination-port 1723 --jump ACCEPT 
.fi
.P

.SH "SEE ALSO"
.BR pppd (8),
.BR pptpd (8),
.BR pptpd.conf (5).