[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 spoof packets from other nodes. And "network"
    means that more than two parties - many so-called vpn solutions only
    create point-to-point tunnels - can participate in the network, so it's
    possible to connect multiple branches of a company into a single
    network.


==   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:	1.3
Committed:	Tue Mar 25 18:11:58 2003 UTC (21 years, 10 months ago) by pcg
Branch:	MAIN
Changes since 1.2:	+43 -37 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			nodes. "Private" means that non-participating nodes cannot decode
15			("sniff)" nor inject ("spoof") packets. In the case of vpe, even
16			participating nodes cannot spoof packets from other nodes. And "network"
17			means that more than two parties - many so-called vpn solutions only
18			create point-to-point tunnels - can participate in the network, so it's
19			possible to connect multiple branches of a company into a single
20			network.
21
22
23			== DESIGN GOALS ==
24
25			: SIMPLE DESIGN
26			Cipher, HMAC algorithms and other key parameters must be selected at
27			compile time - this makes it possible to only link in algorithms you
28			actually need. It also makes the crypto part of the source very
29			transparent and easy to inspect.
30
31			: EASY TO SETUP
32			A few lines of config (the config file is shared unmodified between
33			all hosts) and a single run of ``vpectrl'' to generate the keys
34			suffices to make it work.
35
36			: MAC-BASED SECURITY
37			Since every host has it's own private key, other hosts cannot spoof
38			traffic from this host. That makes it possible to filter packest by
39			MAC address, e.g. to ensure that packets from a specific IP address
40			come, in fact, from a specific host.
41
42
43			==== PROGRAMS ====
44
45			Vpe comes with two programs: one daemon (``vped'') and one control
46	pcg	1.3	program (``vpectrl'').
47	pcg	1.2
48			: vpectrl
49	pcg	1.3	Is used to generate the keys, check and give an overview of of the
50			configuration and contorl the daemon (restarting etc.).
51	pcg	1.2
52			: vped
53			Is the daemon used to establish and maintain conenctions to the
54			other network members. It should be run on the gateway machine.
55
56
57	pcg	1.3	==== COMPILETIME CONFIGURATION ====
58	pcg	1.2
59	pcg	1.3	Here are a few recipes for compiling your vpe:
60	pcg	1.2
61
62			== AS LOW PACKET OVERHEAD AS POSSIBLE ==
63
64	pcg	1.3	./configure --enable-hmac-length=4 --enable-rand-length=0
65	pcg	1.2
66	pcg	1.3	Minimize the header overhead of VPN packets (the above will result in
67			only 4 bytes of overhead over the raw ethernet frame).
68	pcg	1.2
69
70			== MINIMIZE CPU TIME REQUIRED ==
71
72	pcg	1.3	./configure --enable-cipher=bf --enable-digest=md4
73	pcg	1.2
74	pcg	1.3	Use the fastest cipher and digest algorithms currently available in vpe.
75	pcg	1.2
76
77			== MAXIMIZE SECURITY ==
78
79	pcg	1.3	./configure --enable-hmac-length=16 --enable-rand-length=8 --enable-digest=sha1
80
81			This uses a 16 byte HMAC checksum to authenticate packets (I guess 8-12
82			would also be pretty secure ;) and will additionally prefix each packet
83			with 8 bytes of random data.
84	pcg	1.2
85			In general, remember that AES-128 seems to be more secure and faster
86	pcg	1.3	than AES-192 or AES-256, more randomness helps against sniffing and a
87			longer HMAC helps against spoofing. MD4 is a fast digest, SHA1 or
88			RIPEMD160 are better, and Blowfish is a fast cipher (and also quite
89			secure).
90	pcg	1.2
91
92			==== HOW TO SET UP A SIMPLE VPN ====
93
94			In this section I will describe how to get a simple VPN consisting of
95			three hosts up and running.
96
97
98			== STEP 1: configuration ==
99
100			First you have to create a daemon configuation file and put it into the
101			configuration directory. This is usually ``/etc/vpe'', depending on how
102			you configured vpe, and can be overwritten using the ``-c'' commandline
103			switch.
104
105			Put the following lines into ``/etc/vpe/vped.conf'':
106
107	pcg	1.3	udp-port = 50000 # the external port to listen on (configure your firewall)
108			mtu = 1400 # minimum MTU of all outgoing interfaces on all hosts
109			ifname = vpn0 # the local network device name
110	pcg	1.2
111	pcg	1.3	node = first # just a nickname
112			hostname = first.example.net # the DNS name or IP address of the host
113	pcg	1.2
114	pcg	1.3	node = second
115			hostname = 133.55.82.9
116	pcg	1.2
117	pcg	1.3	node = third
118			hostname = third.example.net
119	pcg	1.2
120			The only other file neccessary if the ``if-up'' script that initializes
121			the local ethernet interface. Put the following lines into
122			``/etc/vpe/if-up'' and make it execute (``chmod 755 /etc/vpe/if-up''):
123
124	pcg	1.3	#!/bin/sh
125			ip link set $IFNAME address $MAC mtu $MTU up
126			[ $NODENAME = first ] && ip addr add 10.0.1.1 dev $IFNAME
127			[ $NODENAME = second ] && ip addr add 10.0.2.1 dev $IFNAME
128			[ $NODENAME = third ] && ip addr add 10.0.3.1 dev $IFNAME
129			ip route add 10.0.0.0/16 dev $IFNAME
130	pcg	1.2
131			This script will give each node a different IP address in the
132			``10.0/16'' network. The internal network (e.g. the ``eth0'' interface)
133			should then be set to a subset of that network, e.g. ``10.0.1.0/24'' on
134			node ``first'', ``10.0.2.0/24'' on node ``second'', and so on.
135
136			By enabling routing on the gateway host that runs ``vped'' all nodes
137			will be able to reach the other nodes. You can, of course, also use
138			proxy arp or other means of pseudo-bridging (or even real briding), or
139			(best) full routing - the choice is yours.
140
141
142			== STEP 2: create the RSA key pairs for all hosts ==
143
144			Run the following command to generate all key pairs (that might take a
145			while):
146
147	pcg	1.3	vpectrl -c /etc/vpe -g
148	pcg	1.2
149			This command will put the public keys into
150			``/etc/vpe/pubkeys/nodename'' and the private keys into
151			``/etc/vpe/hostkeys/nodename''.
152
153
154			== STEP 3: distribute the config files to all nodes ==
155
156			Now distribute the config files to the other nodes. This should be done
157			in two steps, since the private keys should not be distributed. The
158			example uses rsync-over-ssh
159
160			First all the config files without the hostkeys should be distributed:
161
162	pcg	1.3	rsync -avzessh /etc/vpe first.example.net:/etc/. --exclude hostkeys
163			rsync -avzessh /etc/vpe 133.55.82.9:/etc/. --exclude hostkeys
164			rsync -avzessh /etc/vpe third.example.net:/etc/. --exclude hostkeys
165	pcg	1.2
166			Then the hostkeys should be copied:
167
168	pcg	1.3	rsync -avzessh /etc/vpe/hostkeys/first first.example.net:/etc/hostkey
169			rsync -avzessh /etc/vpe/hostkeys/second 133.55.82.9:/etc/hostkey
170			rsync -avzessh /etc/vpe/hostkeys/third third.example.net:/etc/hostkey
171	pcg	1.2
172			You should now check the configration by issuing the command ``vpectrl
173			-c /etc/vpe -s'' on each node and verify it's output.
174
175
176			== STEP 4: starting vped ==
177
178			You should then start vped on each node by issuing a command like:
179
180	pcg	1.3	vped -D -linfo first # first is the nodename
181	pcg	1.2
182			This will make the vped stay in foreground. You should then see
183			"connection established" messages. If you don't see them check your
184			firewall and routing (use tcpdump ;).
185
186			If this works you should check your networking setup by pinging various
187			endpoints.
188
189			To make vped run more permanently you can either run it as a daemon (by
190			starting it without the ``-D'' switch), or, much better, from your
191			inittab. I use a line like this on my systems:
192
193	pcg	1.3	t1:2345:respawn:/opt/vpe/sbin/vped -D -L first >/dev/null 2>&1
194	pcg	1.2
195
196			== STEP 5: enjoy ==
197
198			... and play around. Sending a -HUP (``vpectrl -kHUP'') to the daemon
199			will make it try to connect to all other nodes again. If you run it from
200			inittab, as is recommended, ``vpectrl -k'' (or simply ``killall vped'')
201			will kill the daemon, start it again, making it read it's configuration
202			files again.
203
204
205			==== SEE ALSO ====
206
207			vpe(8), vpectrl(8), vped.conf(5).
208
209
210			==== AUTHOR ====
211
212			Marc Lehmann <vpe@plan9.de>
213