edge - n2n edge node daemon
edge [-d <tun device>] -a <tun IP address> -c
<community> {-k <encrypt key>|-K <keyfile>} [-s
<netmask>] -l <supernode host:port> [-p <local port>] [-u
<UID>] [-g <GID>] [-f] [-m <MAC address>] [-r] [-v]
N2N is a peer-to-peer VPN system. Edge is the edge node daemon for n2n which
creates a TAP interface to expose the n2n virtual LAN. On startup n2n creates
the TAP interface and configures it then registers with the supernode so it
can begin to find other nodes in the community.
- -d <name>
- sets the TAP device name as seen in ifconfig. Only available on
Linux.
- -a {<addr>|static:<addr>|dhcp:0.0.0.0}
- sets the n2n virtual LAN IP address being claimed. This is a private IP
address. All IP addresses in an n2n community typical belong to the same
/24 network (ie. only the last octet of the IP addresses varies). If DHCP
is used to assign interface addresses then specify the address as -a
dhcp:0.0.0.0
- -b
- cause edge to perform hostname resolution for the supernode address each
time the supernode is periodically contacted. This can cause reliability
problems because all packet processing stops while the supernode address
is resolved which might take 15 seconds.
- -c <community>
- sets the n2n community name. All edges within the same community appear on
the same LAN (layer 2 network segment). Community name is 16 bytes in
length. A name smaller than this is padded with 0x00 bytes and a name
longer than this is truncated to take the first 16 bytes.
- -h
- write usage then exit.
- -k <keystring>
- sets the twofish encryption key from ASCII text (see also N2N_KEY in
ENVIRONMENT). All edges communicating must use the same key and community
name. If neither -k nor -K is used to specify a key source then edge uses
cleartext mode (no encryption). The -k and -K options are mutually
exclusive.
- -K <keyfile>
- Reads a key-schedule file <keyfile> and populates the internal
transform operations with the data found there. This mechanism allows keys
to roll at pre-determined times for a group of hosts. Accurate time
synchronisation is not required as older keys can be decoded for some time
after expiry. If neither -k nor -K is used to specify a key source then
edge uses cleartext mode (no encryption). The -k and -K options are
mutually exclusive.
- -l <addr>:<port>
- sets the n2n supernode IP address and port to register to. Up to 2
supernodes can be specified by two invocations of -l
<addr>:<port>. eg. edge -l 12.34.56.78:7654 -l
98.76.54.32:7654
- -p <num>
- binds edge to the given UDP port. Useful for keeping the same external
socket across restarts of edge. This allows peer edges which know the edge
socket to continue p2p operation without going back to the supernode.
- -t <num>
- binds the edge management system to the given UDP port. Default 5644. Use
this if you need to run multiple instance of edge; or something is bound
to that port.
- -u <uid>
- causes the edge process to drop to the given user ID when privileges are
no longer required (UNIX).
- -g <gid>
- causes the edge process to drop to the given group ID when privileges are
no longer required (UNIX).
- -f
- disables daemon mode (UNIX) and causes edge to run in the foreground.
- -m <MAC>
- start the TAP interface with the given MAC address. This is highly
recommended as it means the same address will be used if edge stops and
restarts. If this is not done, the ARP caches of all peers will be wrong
and packets will not flow to this edge until the next ARP refresh.
- -M <MTU>
- set the MTU of the edge interface in bytes. MTU is the largest packet
fragment size allowed to be moved throught the interface. The default is
1400.
- -s <netmask>
- set the netmask of edge interface in IPv4 dotted decimal notation. The
default is 255.255.255.0 (ie. /24).
- -r
- enable IP packet forwarding/routing through the n2n virtual LAN. Without
this option, IP packets arriving over n2n are dropped if not for the -a
<addr> (or DHCP assigned) IP address of the edge interface.
- -E
- accept packets destined for multicast ethernet MAC addresses. These
addresses are used in multicast ethernet and IPv6 neighbour discovery. If
this option is not present these multicast packets are discarded as most
users do not need or understand them.
- -v
- more verbose logging (may be specified several times for more
verbosity).
- N2N_KEY
- set the encryption key so it is not visible on the command line
- edge -d n2n0 -c mynetwork -k encryptme -u 99 -g 99 -m DE:AD:BE:EF:01:23
-a 192.168.254.7 -p 50001 -l 123.121.120.119:7654
-
Start edge with TAP device n2n0 on community "mynetwork" with
community supernode at 123.121.120.119 UDP port 7654 and bind the locally
used UDP port to 50001. Use "encryptme" as the single permanent
shared encryption key. Assign MAC address DE:AD:BE:EF:01:23 to the n2n
interface and drop to user=99 and group=99 after the TAP device is
successfull configured.
Add the -f option to stop edge running as a daemon.
Somewhere else setup another edge with similar parameters, eg.
edge -d n2n0 -c mynetwork -k encryptme -u 99 -g 99 -m DE:AD:BE:EF:01:21 -a
192.168.254.5 -p 50001 -l 123.121.120.119:7654
Now you can ping from 192.168.254.5 to 192.168.254.7.
The MAC address (-m <MAC>) and virtual IP address (-a <addr>) must
be different on all edges in the same community.
(See
n2n_v2(7) for more details).
The -K <keyfile> option reads a key schedule file.
edge -d n2n0 -c mynetwork -K /path/to/file -u 99 -g 99 -m DE:AD:BE:EF:01:21
-a 192.168.254.5 -p 50001 -l 123.121.120.119:7654
The key schedule file consists of line, one per key in the schedule. The purpose
of key schedules is to encourage regular changing of the encryption keys used
by a community. The file structure also allows for full binary keys to be
specified as compared to the ASCII keys allowed by the single key injection.
Each key line consists of the following:
<from> <until> <transform> <data>
<from> and <until> are ASCII decimal values of the UNIX times during
which the key is valid. <transform> is the index of the transform that
<data> applies to. <data> is some text which is parsed by the
transform module to derive the key for that line.
Supported <transform> values are:
- 2 = TwoFish
- <data> has the form <SA>_<hex_key>. eg.
1252327945 1252328305 2 602_3d7c7769b34b2a4812f8c0e9d87ce9
This specifies security association number 602 and a 16-octet key of numeric
value 0x3d7c7769b34b2a4812f8c0e9d87ce9. <SA> is a 32-bit unsigned
integer which is used to identify the encryption key to the receiver. The
SA number is sent unencrypted so the receiver may find the correct key
from the key schedule. <hex_key> is up to 16 octets although shorter
keys are allowed.
- 3 = AES-CBC
- <data> has the form <SA>_<hex_key>. Same rules as
TwoFish.
If neither
-k nor
-K is specified then edge uses cleartext mode.
In cleartext mode there is no transform of the packet data it is simply
encrypted. This is useful for debugging n2n as packet contents can be seen
clearly.
To prevent accidental exposure of data, edge only enters cleartext mode when no
keying parameters are specified. In the case where keying parameters are
specified but no valid keys can be determined, edge exits with an error at
startup. If all keys become invalid while running, edge continues to encode
using the last key that was valid.
Edge provides a very simple management system on UDP port 5644. Send a newline
to receive a status output. Send 'reload' to cause re-read of the keyfile.
Send 'stop' to cause edge to exit cleanly.
edge is a daemon and any exit is an error.
- Richard Andrews
- andrews (at) ntop.org - n2n-1 maintainer and main author of n2n-2
- Luca Deri
- deri (at) ntop.org - original author of n2n
- Don Bindner
- (--) - significant contributions to n2n-1
ifconfig(8) supernode(1) tunctl(8) n2n_v2(7)