[ViewVC] Annotation of: cvs/gvpe/README


==== NAME ====

    GNU-VPE - Overview of the GNU Virtual Private Ethernet suite.


==== DESCRIPTION ====

    Vpe is a suite designed to provide a virtual private network for
    multiple nodes over an untrusted network.

    "Virtual" means that no physical network is created (of course), but an
    ethernet is emulated by creating multiple tunnels between the member
    nodes.

    "Private" means that non-participating nodes cannot decode ("sniff)" nor
    inject ("spoof") packets.

    In the case of vpe, even participating nodes cannot sniff packets send
    to other nodes or spoof packets as if sent from other nodes.

    "Network" means that more than two parties can participate in the
    network, so for instance it's possible to connect multiple branches of a
    company into a single network. Many so-called "vpn" solutions only
    create point-to-point tunnels.


==   DESIGN GOALS   ==

:   SIMPLE DESIGN
        Cipher, HMAC algorithms and other key parameters must be selected at
        compile time - this makes it possible to only link in algorithms you
        actually need. It also makes the crypto part of the source very
        transparent and easy to inspect.

:   EASY TO SETUP
        A few lines of config (the config file is shared unmodified between
        all hosts) and a single run of ``vpectrl'' to generate the keys
        suffices to make it work.

:   MAC-BASED SECURITY
        Since every host has it's own private key, other hosts cannot spoof
        traffic from this host. That makes it possible to filter packest by
        MAC address, e.g. to ensure that packets from a specific IP address
        come, in fact, from a specific host.


==== PROGRAMS ====

    Vpe comes with two programs: one daemon (``vped'') and one control
    program (``vpectrl'').

:   vpectrl
        Is used to generate the keys, check and give an overview of of the
        configuration and contorl the daemon (restarting etc.).

:   vped
        Is the daemon used to establish and maintain conenctions to the
        other network members. It should be run on the gateway machine.


==== COMPILETIME CONFIGURATION ====

    Please have a look at the ``vpe.osdep(5)'' manpage for platform-specific
    information.

    Here are a few recipes for compiling your vpe:


==   AS LOW PACKET OVERHEAD AS POSSIBLE   ==

       ./configure --enable-hmac-length=4 --enable-rand-length=0

    Minimize the header overhead of VPN packets (the above will result in
    only 4 bytes of overhead over the raw ethernet frame).


==   MINIMIZE CPU TIME REQUIRED   ==

       ./configure --enable-cipher=bf --enable-digest=md4

    Use the fastest cipher and digest algorithms currently available in vpe.


==   MAXIMIZE SECURITY   ==

       ./configure --enable-hmac-length=16 --enable-rand-length=8 --enable-digest=sha1

    This uses a 16 byte HMAC checksum to authenticate packets (I guess 8-12
    would also be pretty secure ;) and will additionally prefix each packet
    with 8 bytes of random data.

    In general, remember that AES-128 seems to be more secure and faster
    than AES-192 or AES-256, more randomness helps against sniffing and a
    longer HMAC helps against spoofing. MD4 is a fast digest, SHA1 or
    RIPEMD160 are better, and Blowfish is a fast cipher (and also quite
    secure).


==== HOW TO SET UP A SIMPLE VPN ====

    In this section I will describe how to get a simple VPN consisting of
    three hosts up and running.


==   STEP 1: configuration   ==

    First you have to create a daemon configuation file and put it into the
    configuration directory. This is usually ``/etc/vpe'', depending on how
    you configured vpe, and can be overwritten using the ``-c'' commandline
    switch.

    Put the following lines into ``/etc/vpe/vped.conf'':

       udp-port = 50000 # the external port to listen on (configure your firewall)
       mtu = 1400       # minimum MTU of all outgoing interfaces on all hosts
       ifname = vpn0    # the local network device name

       node = first     # just a nickname
       hostname = first.example.net # the DNS name or IP address of the host

       node = second
       hostname = 133.55.82.9

       node = third
       hostname = third.example.net

    The only other file neccessary if the ``if-up'' script that initializes
    the local ethernet interface. Put the following lines into
    ``/etc/vpe/if-up'' and make it execute (``chmod 755 /etc/vpe/if-up''):

       #!/bin/sh
       ip link set $IFNAME address $MAC mtu $MTU up
       [ $NODENAME = first  ] && ip addr add 10.0.1.1 dev $IFNAME
       [ $NODENAME = second ] && ip addr add 10.0.2.1 dev $IFNAME
       [ $NODENAME = third  ] && ip addr add 10.0.3.1 dev $IFNAME
       ip route add 10.0.0.0/16 dev $IFNAME

    This script will give each node a different IP address in the
    ``10.0/16'' network. The internal network (e.g. the ``eth0'' interface)
    should then be set to a subset of that network, e.g. ``10.0.1.0/24'' on
    node ``first'', ``10.0.2.0/24'' on node ``second'', and so on.

    By enabling routing on the gateway host that runs ``vped'' all nodes
    will be able to reach the other nodes. You can, of course, also use
    proxy arp or other means of pseudo-bridging (or even real briding), or
    (best) full routing - the choice is yours.


==   STEP 2: create the RSA key pairs for all hosts   ==

    Run the following command to generate all key pairs (that might take a
    while):

       vpectrl -c /etc/vpe -g

    This command will put the public keys into
    ``/etc/vpe/pubkeys/*nodename*'' and the private keys into
    ``/etc/vpe/hostkeys/*nodename*''.


==   STEP 3: distribute the config files to all nodes   ==

    Now distribute the config files to the other nodes. This should be done
    in two steps, since the private keys should not be distributed. The
    example uses rsync-over-ssh

    First all the config files without the hostkeys should be distributed:

       rsync -avzessh /etc/vpe first.example.net:/etc/. --exclude hostkeys
       rsync -avzessh /etc/vpe 133.55.82.9:/etc/. --exclude hostkeys
       rsync -avzessh /etc/vpe third.example.net:/etc/. --exclude hostkeys

    Then the hostkeys should be copied:

       rsync -avzessh /etc/vpe/hostkeys/first  first.example.net:/etc/hostkey
       rsync -avzessh /etc/vpe/hostkeys/second 133.55.82.9:/etc/hostkey
       rsync -avzessh /etc/vpe/hostkeys/third  third.example.net:/etc/hostkey

    You should now check the configration by issuing the command ``vpectrl
    -c /etc/vpe -s'' on each node and verify it's output.


==   STEP 4: starting vped   ==

    You should then start vped on each node by issuing a command like:

       vped -D -linfo first # first is the nodename

    This will make the vped stay in foreground. You should then see
    "connection established" messages. If you don't see them check your
    firewall and routing (use tcpdump ;).

    If this works you should check your networking setup by pinging various
    endpoints.

    To make vped run more permanently you can either run it as a daemon (by
    starting it without the ``-D'' switch), or, much better, from your
    inittab. I use a line like this on my systems:

       t1:2345:respawn:/opt/vpe/sbin/vped -D -L first >/dev/null 2>&1


==   STEP 5: enjoy   ==

    ... and play around. Sending a -HUP (``vpectrl -kHUP'') to the daemon
    will make it try to connect to all other nodes again. If you run it from
    inittab, as is recommended, ``vpectrl -k'' (or simply ``killall vped'')
    will kill the daemon, start it again, making it read it's configuration
    files again.


==== SEE ALSO ====

    vpe.osdep(5) for OS-depedendent information, vped.conf(5), vpectrl(8),
    and for a description of the protocol and routing algorithms,
    vpe.protocol(7).


==== AUTHOR ====

    Marc Lehmann <vpe@plan9.de>


==== COPYRIGHTS AND LICENSES ====

    Vpe itself is distributed under the GENERAL PUBLIC LICENSE (see the file
    COPYING that should be part of your distribution).

    In some configurations it uses modified versions of the tinc vpn suite,
    which is also available under the GENERAL PUBLIC LICENSE.

    In some configurations (notably darwin), it uses a poll emulation
    library that comes with the following license notice:

      Copyright (c) 1995-2002 Brian M. Clapper
      All rights reserved.

      Redistribution and use in source and binary forms are permitted
      provided that: (1) source distributions retain this entire
      copyright notice and comment; (2) modifications made to the
      software are prominently mentioned, and a copy of the original
      software (or a pointer to its location) are included; and (3)
      distributions including binaries display the following
      acknowledgement: "This product includes software developed by Brian
      M. Clapper <bmc@clapper.org>" in the documentation or other
      materials provided with the distribution. The name of the author
      may not be used to endorse or promote products derived from this
      software without specific prior written permission.

      THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
      IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
      WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

Revision:	1.6
Committed:	Mon Jun 7 03:21:16 2004 UTC (19 years, 11 months ago) by pcg
Branch:	MAIN
Changes since 1.5:	+38 -2 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	pcg	1.1
2	pcg	1.2	==== NAME ====
3
4	pcg	1.6	GNU-VPE - Overview of the GNU Virtual Private Ethernet suite.
5	pcg	1.2
6
7			==== DESCRIPTION ====
8
9			Vpe is a suite designed to provide a virtual private network for
10			multiple nodes over an untrusted network.
11
12			"Virtual" means that no physical network is created (of course), but an
13			ethernet is emulated by creating multiple tunnels between the member
14	pcg	1.4	nodes.
15
16			"Private" means that non-participating nodes cannot decode ("sniff)" nor
17			inject ("spoof") packets.
18
19			In the case of vpe, even participating nodes cannot sniff packets send
20			to other nodes or spoof packets as if sent from other nodes.
21
22			"Network" means that more than two parties can participate in the
23			network, so for instance it's possible to connect multiple branches of a
24			company into a single network. Many so-called "vpn" solutions only
25			create point-to-point tunnels.
26	pcg	1.2
27
28			== DESIGN GOALS ==
29
30			: SIMPLE DESIGN
31			Cipher, HMAC algorithms and other key parameters must be selected at
32			compile time - this makes it possible to only link in algorithms you
33			actually need. It also makes the crypto part of the source very
34			transparent and easy to inspect.
35
36			: EASY TO SETUP
37			A few lines of config (the config file is shared unmodified between
38			all hosts) and a single run of ``vpectrl'' to generate the keys
39			suffices to make it work.
40
41			: MAC-BASED SECURITY
42			Since every host has it's own private key, other hosts cannot spoof
43			traffic from this host. That makes it possible to filter packest by
44			MAC address, e.g. to ensure that packets from a specific IP address
45			come, in fact, from a specific host.
46
47
48			==== PROGRAMS ====
49
50			Vpe comes with two programs: one daemon (``vped'') and one control
51	pcg	1.3	program (``vpectrl'').
52	pcg	1.2
53			: vpectrl
54	pcg	1.3	Is used to generate the keys, check and give an overview of of the
55			configuration and contorl the daemon (restarting etc.).
56	pcg	1.2
57			: vped
58			Is the daemon used to establish and maintain conenctions to the
59			other network members. It should be run on the gateway machine.
60
61
62	pcg	1.3	==== COMPILETIME CONFIGURATION ====
63	pcg	1.2
64	pcg	1.6	Please have a look at the ``vpe.osdep(5)'' manpage for platform-specific
65			information.
66
67	pcg	1.3	Here are a few recipes for compiling your vpe:
68	pcg	1.2
69
70			== AS LOW PACKET OVERHEAD AS POSSIBLE ==
71
72	pcg	1.3	./configure --enable-hmac-length=4 --enable-rand-length=0
73	pcg	1.2
74	pcg	1.3	Minimize the header overhead of VPN packets (the above will result in
75			only 4 bytes of overhead over the raw ethernet frame).
76	pcg	1.2
77
78			== MINIMIZE CPU TIME REQUIRED ==
79
80	pcg	1.3	./configure --enable-cipher=bf --enable-digest=md4
81	pcg	1.2
82	pcg	1.3	Use the fastest cipher and digest algorithms currently available in vpe.
83	pcg	1.2
84
85			== MAXIMIZE SECURITY ==
86
87	pcg	1.3	./configure --enable-hmac-length=16 --enable-rand-length=8 --enable-digest=sha1
88
89			This uses a 16 byte HMAC checksum to authenticate packets (I guess 8-12
90			would also be pretty secure ;) and will additionally prefix each packet
91			with 8 bytes of random data.
92	pcg	1.2
93			In general, remember that AES-128 seems to be more secure and faster
94	pcg	1.3	than AES-192 or AES-256, more randomness helps against sniffing and a
95			longer HMAC helps against spoofing. MD4 is a fast digest, SHA1 or
96			RIPEMD160 are better, and Blowfish is a fast cipher (and also quite
97			secure).
98	pcg	1.2
99
100			==== HOW TO SET UP A SIMPLE VPN ====
101
102			In this section I will describe how to get a simple VPN consisting of
103			three hosts up and running.
104
105
106			== STEP 1: configuration ==
107
108			First you have to create a daemon configuation file and put it into the
109			configuration directory. This is usually ``/etc/vpe'', depending on how
110			you configured vpe, and can be overwritten using the ``-c'' commandline
111			switch.
112
113			Put the following lines into ``/etc/vpe/vped.conf'':
114
115	pcg	1.3	udp-port = 50000 # the external port to listen on (configure your firewall)
116			mtu = 1400 # minimum MTU of all outgoing interfaces on all hosts
117			ifname = vpn0 # the local network device name
118	pcg	1.2
119	pcg	1.3	node = first # just a nickname
120			hostname = first.example.net # the DNS name or IP address of the host
121	pcg	1.2
122	pcg	1.3	node = second
123			hostname = 133.55.82.9
124	pcg	1.2
125	pcg	1.3	node = third
126			hostname = third.example.net
127	pcg	1.2
128			The only other file neccessary if the ``if-up'' script that initializes
129			the local ethernet interface. Put the following lines into
130			``/etc/vpe/if-up'' and make it execute (``chmod 755 /etc/vpe/if-up''):
131
132	pcg	1.3	#!/bin/sh
133			ip link set $IFNAME address $MAC mtu $MTU up
134			[ $NODENAME = first ] && ip addr add 10.0.1.1 dev $IFNAME
135			[ $NODENAME = second ] && ip addr add 10.0.2.1 dev $IFNAME
136			[ $NODENAME = third ] && ip addr add 10.0.3.1 dev $IFNAME
137			ip route add 10.0.0.0/16 dev $IFNAME
138	pcg	1.2
139			This script will give each node a different IP address in the
140			``10.0/16'' network. The internal network (e.g. the ``eth0'' interface)
141			should then be set to a subset of that network, e.g. ``10.0.1.0/24'' on
142			node ``first'', ``10.0.2.0/24'' on node ``second'', and so on.
143
144			By enabling routing on the gateway host that runs ``vped'' all nodes
145			will be able to reach the other nodes. You can, of course, also use
146			proxy arp or other means of pseudo-bridging (or even real briding), or
147			(best) full routing - the choice is yours.
148
149
150			== STEP 2: create the RSA key pairs for all hosts ==
151
152			Run the following command to generate all key pairs (that might take a
153			while):
154
155	pcg	1.3	vpectrl -c /etc/vpe -g
156	pcg	1.2
157			This command will put the public keys into
158			``/etc/vpe/pubkeys/nodename'' and the private keys into
159			``/etc/vpe/hostkeys/nodename''.
160
161
162			== STEP 3: distribute the config files to all nodes ==
163
164			Now distribute the config files to the other nodes. This should be done
165			in two steps, since the private keys should not be distributed. The
166			example uses rsync-over-ssh
167
168			First all the config files without the hostkeys should be distributed:
169
170	pcg	1.3	rsync -avzessh /etc/vpe first.example.net:/etc/. --exclude hostkeys
171			rsync -avzessh /etc/vpe 133.55.82.9:/etc/. --exclude hostkeys
172			rsync -avzessh /etc/vpe third.example.net:/etc/. --exclude hostkeys
173	pcg	1.2
174			Then the hostkeys should be copied:
175
176	pcg	1.3	rsync -avzessh /etc/vpe/hostkeys/first first.example.net:/etc/hostkey
177			rsync -avzessh /etc/vpe/hostkeys/second 133.55.82.9:/etc/hostkey
178			rsync -avzessh /etc/vpe/hostkeys/third third.example.net:/etc/hostkey
179	pcg	1.2
180			You should now check the configration by issuing the command ``vpectrl
181			-c /etc/vpe -s'' on each node and verify it's output.
182
183
184			== STEP 4: starting vped ==
185
186			You should then start vped on each node by issuing a command like:
187
188	pcg	1.3	vped -D -linfo first # first is the nodename
189	pcg	1.2
190			This will make the vped stay in foreground. You should then see
191			"connection established" messages. If you don't see them check your
192			firewall and routing (use tcpdump ;).
193
194			If this works you should check your networking setup by pinging various
195			endpoints.
196
197			To make vped run more permanently you can either run it as a daemon (by
198			starting it without the ``-D'' switch), or, much better, from your
199			inittab. I use a line like this on my systems:
200
201	pcg	1.3	t1:2345:respawn:/opt/vpe/sbin/vped -D -L first >/dev/null 2>&1
202	pcg	1.2
203
204			== STEP 5: enjoy ==
205
206			... and play around. Sending a -HUP (``vpectrl -kHUP'') to the daemon
207			will make it try to connect to all other nodes again. If you run it from
208			inittab, as is recommended, ``vpectrl -k'' (or simply ``killall vped'')
209			will kill the daemon, start it again, making it read it's configuration
210			files again.
211
212
213			==== SEE ALSO ====
214
215	pcg	1.6	vpe.osdep(5) for OS-depedendent information, vped.conf(5), vpectrl(8),
216			and for a description of the protocol and routing algorithms,
217			vpe.protocol(7).
218	pcg	1.2
219
220			==== AUTHOR ====
221
222			Marc Lehmann <vpe@plan9.de>
223	pcg	1.6
224
225			==== COPYRIGHTS AND LICENSES ====
226
227			Vpe itself is distributed under the GENERAL PUBLIC LICENSE (see the file
228			COPYING that should be part of your distribution).
229
230			In some configurations it uses modified versions of the tinc vpn suite,
231			which is also available under the GENERAL PUBLIC LICENSE.
232
233			In some configurations (notably darwin), it uses a poll emulation
234			library that comes with the following license notice:
235
236			Copyright (c) 1995-2002 Brian M. Clapper
237			All rights reserved.
238
239			Redistribution and use in source and binary forms are permitted
240			provided that: (1) source distributions retain this entire
241			copyright notice and comment; (2) modifications made to the
242			software are prominently mentioned, and a copy of the original
243			software (or a pointer to its location) are included; and (3)
244			distributions including binaries display the following
245			acknowledgement: "This product includes software developed by Brian
246			M. Clapper <bmc@clapper.org>" in the documentation or other
247			materials provided with the distribution. The name of the author
248			may not be used to endorse or promote products derived from this
249			software without specific prior written permission.
250
251			THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
252			IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
253			WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
254	pcg	1.2