[ViewVC] Annotation of: cvs/gvpe/README


==== NAME ====

    vpe - Overview of the 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 ====

    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(8), vpectrl(8), vped.conf(5).


==== AUTHOR ====

    Marc Lehmann <vpe@plan9.de>

Revision:	1.4
Committed:	Wed Mar 26 02:12:16 2003 UTC (21 years, 10 months ago) by pcg
Branch:	MAIN
Changes since 1.3:	+12 -7 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	pcg	1.1
2	pcg	1.2	==== NAME ====
3
4			vpe - Overview of the virtual private ethernet suite.
5
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	1.3	Here are a few recipes for compiling your vpe:
65	pcg	1.2
66
67			== AS LOW PACKET OVERHEAD AS POSSIBLE ==
68
69	pcg	1.3	./configure --enable-hmac-length=4 --enable-rand-length=0
70	pcg	1.2
71	pcg	1.3	Minimize the header overhead of VPN packets (the above will result in
72			only 4 bytes of overhead over the raw ethernet frame).
73	pcg	1.2
74
75			== MINIMIZE CPU TIME REQUIRED ==
76
77	pcg	1.3	./configure --enable-cipher=bf --enable-digest=md4
78	pcg	1.2
79	pcg	1.3	Use the fastest cipher and digest algorithms currently available in vpe.
80	pcg	1.2
81
82			== MAXIMIZE SECURITY ==
83
84	pcg	1.3	./configure --enable-hmac-length=16 --enable-rand-length=8 --enable-digest=sha1
85
86			This uses a 16 byte HMAC checksum to authenticate packets (I guess 8-12
87			would also be pretty secure ;) and will additionally prefix each packet
88			with 8 bytes of random data.
89	pcg	1.2
90			In general, remember that AES-128 seems to be more secure and faster
91	pcg	1.3	than AES-192 or AES-256, more randomness helps against sniffing and a
92			longer HMAC helps against spoofing. MD4 is a fast digest, SHA1 or
93			RIPEMD160 are better, and Blowfish is a fast cipher (and also quite
94			secure).
95	pcg	1.2
96
97			==== HOW TO SET UP A SIMPLE VPN ====
98
99			In this section I will describe how to get a simple VPN consisting of
100			three hosts up and running.
101
102
103			== STEP 1: configuration ==
104
105			First you have to create a daemon configuation file and put it into the
106			configuration directory. This is usually ``/etc/vpe'', depending on how
107			you configured vpe, and can be overwritten using the ``-c'' commandline
108			switch.
109
110			Put the following lines into ``/etc/vpe/vped.conf'':
111
112	pcg	1.3	udp-port = 50000 # the external port to listen on (configure your firewall)
113			mtu = 1400 # minimum MTU of all outgoing interfaces on all hosts
114			ifname = vpn0 # the local network device name
115	pcg	1.2
116	pcg	1.3	node = first # just a nickname
117			hostname = first.example.net # the DNS name or IP address of the host
118	pcg	1.2
119	pcg	1.3	node = second
120			hostname = 133.55.82.9
121	pcg	1.2
122	pcg	1.3	node = third
123			hostname = third.example.net
124	pcg	1.2
125			The only other file neccessary if the ``if-up'' script that initializes
126			the local ethernet interface. Put the following lines into
127			``/etc/vpe/if-up'' and make it execute (``chmod 755 /etc/vpe/if-up''):
128
129	pcg	1.3	#!/bin/sh
130			ip link set $IFNAME address $MAC mtu $MTU up
131			[ $NODENAME = first ] && ip addr add 10.0.1.1 dev $IFNAME
132			[ $NODENAME = second ] && ip addr add 10.0.2.1 dev $IFNAME
133			[ $NODENAME = third ] && ip addr add 10.0.3.1 dev $IFNAME
134			ip route add 10.0.0.0/16 dev $IFNAME
135	pcg	1.2
136			This script will give each node a different IP address in the
137			``10.0/16'' network. The internal network (e.g. the ``eth0'' interface)
138			should then be set to a subset of that network, e.g. ``10.0.1.0/24'' on
139			node ``first'', ``10.0.2.0/24'' on node ``second'', and so on.
140
141			By enabling routing on the gateway host that runs ``vped'' all nodes
142			will be able to reach the other nodes. You can, of course, also use
143			proxy arp or other means of pseudo-bridging (or even real briding), or
144			(best) full routing - the choice is yours.
145
146
147			== STEP 2: create the RSA key pairs for all hosts ==
148
149			Run the following command to generate all key pairs (that might take a
150			while):
151
152	pcg	1.3	vpectrl -c /etc/vpe -g
153	pcg	1.2
154			This command will put the public keys into
155			``/etc/vpe/pubkeys/nodename'' and the private keys into
156			``/etc/vpe/hostkeys/nodename''.
157
158
159			== STEP 3: distribute the config files to all nodes ==
160
161			Now distribute the config files to the other nodes. This should be done
162			in two steps, since the private keys should not be distributed. The
163			example uses rsync-over-ssh
164
165			First all the config files without the hostkeys should be distributed:
166
167	pcg	1.3	rsync -avzessh /etc/vpe first.example.net:/etc/. --exclude hostkeys
168			rsync -avzessh /etc/vpe 133.55.82.9:/etc/. --exclude hostkeys
169			rsync -avzessh /etc/vpe third.example.net:/etc/. --exclude hostkeys
170	pcg	1.2
171			Then the hostkeys should be copied:
172
173	pcg	1.3	rsync -avzessh /etc/vpe/hostkeys/first first.example.net:/etc/hostkey
174			rsync -avzessh /etc/vpe/hostkeys/second 133.55.82.9:/etc/hostkey
175			rsync -avzessh /etc/vpe/hostkeys/third third.example.net:/etc/hostkey
176	pcg	1.2
177			You should now check the configration by issuing the command ``vpectrl
178			-c /etc/vpe -s'' on each node and verify it's output.
179
180
181			== STEP 4: starting vped ==
182
183			You should then start vped on each node by issuing a command like:
184
185	pcg	1.3	vped -D -linfo first # first is the nodename
186	pcg	1.2
187			This will make the vped stay in foreground. You should then see
188			"connection established" messages. If you don't see them check your
189			firewall and routing (use tcpdump ;).
190
191			If this works you should check your networking setup by pinging various
192			endpoints.
193
194			To make vped run more permanently you can either run it as a daemon (by
195			starting it without the ``-D'' switch), or, much better, from your
196			inittab. I use a line like this on my systems:
197
198	pcg	1.3	t1:2345:respawn:/opt/vpe/sbin/vped -D -L first >/dev/null 2>&1
199	pcg	1.2
200
201			== STEP 5: enjoy ==
202
203			... and play around. Sending a -HUP (``vpectrl -kHUP'') to the daemon
204			will make it try to connect to all other nodes again. If you run it from
205			inittab, as is recommended, ``vpectrl -k'' (or simply ``killall vped'')
206			will kill the daemon, start it again, making it read it's configuration
207			files again.
208
209
210			==== SEE ALSO ====
211
212			vpe(8), vpectrl(8), vped.conf(5).
213
214
215			==== AUTHOR ====
216
217			Marc Lehmann <vpe@plan9.de>
218