path: root/sbin/ipsecadm/ipsecadm.1

.\" $OpenBSD: ipsecadm.1,v 1.8 1999/02/24 22:53:36 angelos Exp $
.\" Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
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.\" Manual page, using -mandoc macros
.\"
.Dd August 26, 1997
.Dt IPSECADM 1
.Os
.Sh NAME
.Nm ipsecadm
.Nd interface to setup IPSec
.Sh SYNOPSIS
.Nm ipsecadm
.Op command
.Ar modifiers ...
.Sh DESCRIPTION
The
.Nm ipsecadm
utility allows sets up security associations in the kernel
to be used with
.Xr ipsec 4 .
It can be used to specify the encryption and authentication
algorithms and key material for the network layer security
provided by IPSec.
The possible commands are:
.Bl -tag -width new_esp
.It new esp
Setup a Security Parameters Index (SPI) which uses the new esp transforms.
Encryption and authentication algorithms can be applied.
This is the default mode.
Allowed
modifiers are:
.Fl dst ,
.Fl src ,
.Fl proxy ,
.Fl spi ,
.Fl enc ,
.Fl auth ,
.Fl authkey ,
.Fl forcetunnel ,
and
.Fl key .
.It old esp
Setup a SPI which uses the old esp transforms. Only
encryption algorithms can be applied. Allowed modifiers are:
.Fl dst ,
.Fl src ,
.Fl proxy ,
.Fl spi ,
.Fl enc ,
.Fl halfiv ,
.Fl forcetunnel , 
and
.Fl key .
.It new ah
Setup a SPI which uses the new ah transforms. Authentication
will be done with HMAC using the specified hash algorithm. Allowed modifiers
are:
.Fl dst ,
.Fl src ,
.Fl proxy ,
.Fl spi ,
.Fl forcetunnel ,
.Fl auth ,
and
.Fl key .
.It old ah
Setup a SPI which uses the old ah transforms. Simple keyed
hashes will be used for authentication. Allowed modifiers are:
.Fl dst ,
.Fl src ,
.Fl proxy ,
.Fl spi ,
.Fl forcetunnel ,
.Fl auth ,
and
.Fl key .
.It ip4
Setup an SPI which uses the IP-in-IP encapsulation protocol. This mode
offers no security services by itself, but can be used to route other
(experimental or otherwise) protocols over an IP network. The SPI value
is not used for anything other than referencing the information, and
does not appear on the wire. Unlike other setups, like new esp, there
is no necessary setup in the receiving side. Allowed modifiers are:
.Fl dst ,
.Fl src ,
and
.Fl spi.
.It delspi
The specified Security Association (SA) will be deleted. An SA consists of
the destination address, SPI and security protocol. Allowed modifiers are:
.Fl dst ,
.Fl spi ,
.Fl proto .
and
.Fl chain .
.It group
Group two SA's together. Allowed modifiers are:
.Fl dst ,
.Fl spi ,
.Fl proto ,
.Fl dst2 ,
.Fl spi2 ,
and
.Fl proto2 .
.It flow
Create a flow determining which packets are routed via which Security
Association. Allowed modifiers are:
.Fl dst ,
.Fl spi ,
.Fl proto ,
.Fl addr ,
.Fl transport ,
.Fl sport ,
.Fl dport ,
.FL local ,
.Fl delete .
The
.Xr netstat 1
command shows the existing flows.
.El
.Pp
If no command is given
.Xr ipsecadm 1
defaults to new esp mode.
.Pp
The modifiers have the following meanings:
.Bl -tag -width forcetunnel -offset indent
.It src
The source IP address for the SPI. This is necessary for incoming
SAs to avoid source address spoofing between mutually
suspicious hosts that have established SAs with us. For outgoing SAs, this
field is used to slightly speedup packet processing. If this field is
zero (0.0.0.0), no spoofing check will be done for incoming SAs, and an
extra routing lookup may be necessary for certain classes of packets that
originate from the local machine and make use of the SA. If present, the
value of this field is used when doing IP-in-IP encapsulation (e.g., when
the
.Nm forcetunnel
option has been specified.
.It dst
The destination IP address for the SPI.
.It proxy
This IP address, if provided, is checked against the inner IP address when
doing tunneling to a firewall, to prevent source spoofing attacks. It is
strongly recommended that this option is provided when applicable. It is
applicable in a scenario when host A is using IPsec to communicate with
firewall B, and through that to host C. In that case, the proxy address for
the incoming SA should be C. This option is not necessary for outgoing SAs.
.It spi
The unique Security Parameter Index (SPI).
.It tunnel
This option has been deprecated. The arguments are ignored, and it
otherwise has the same effect as the
.Nm forcetunnel
option.
.It newpadding
This option has been deprecated.
.It forcetunnel
Force IP-inside-IP encapsulation before ESP or AH processing is performed for
outgoing packets. The source/destination addresses of the outgoing IP packet
will be those provided in the
.Nm src
and
.Nm dst
options. Notice that the IPsec stack will perform IP-inside-IP encapsulation
when deemed necessary, even if this flag has not been set.
.It enc
The encryption algorithm to be used with the SPI. Possible values
are:
.Bl -tag -width skipjack
.It Nm des
This is available for both old and new esp.
Notice that hardware crackers for DES can be (and have been) built for
US$250,000. Use DES for encryption of critical information at your risk.
We suggest using 3DES instead. DES support is kept for interoperability
(with old implementations) purposes only.
.It Nm 3des 
This is available for both old and new esp.  It is more considered to be
more secure than straight DES, since it uses larger keys.
.It Nm blf
Blowfish encryption is available only in new esp.
.It Nm cast
CAST encryption is available only in new esp.
.It Nm skipjack
SKIPJACK encryption is available only in new esp.  This algorithm designed
by the NSA is faster than 3DES.  However, since it was designed by the NSA
it is a poor choice.
.El
.Pp
.It auth
The authentication algorithm to be used with the SPI. Possible values
are:
.Nm md5
and
.Nm sha1
for both old and new ah and also new esp. Also
.Nm rmd160
for both new ah and esp.
.It key
The secret symmetric key used for encryption and authentication. The size
for
.Nm des
and
.Nm 3des
is fixed to 8 and 24 respectively. For other ciphers like
.Nm cast
or
.Nm blf
the key length can be variable. The
.Nm key
should be given in hexadecimal digits. The
.Nm key
should be chosen in random (ideally, using some true-random source like
coin flipping). It is very important that the key is not guessable. One
practical way of generating keys is by using the
.Xr random 4
device (e.g. dd if=/dev/urandom bs=1024 count=1 | sha1)
.It authkey
The secret key material used for authentication
if additional authentication in new esp mode is required. For
old or new ah the key material for authentication is passed with the
.Nm key
option. The
.Nm key
should be given in hexadecimal digits. The
.Nm key
should be chosen in random (ideally, using some true-random source like
coin flipping). It is very important that the key is not guessable. One
practical way of generating keys is by using the
.Xr random 4
device (e.g. dd if=/dev/urandom bs=1024 count=1 | sha1)
.It iv
This option has been deprecated. The argument is ignored. When applicable,
it has the same behaviour as the
.Nm halfiv
option.
.It halfiv
This option causes use of a 4 byte IV in old ESP (as opposed to 8 bytes). It
may only be used with old ESP.
.It proto
The security protocol needed by
.Nm delspi ,
.Nm flow
or
.Nm group
to uniquely specify the SA.
The default value is 50 which means
.Nm IPPROTO_ESP .
Other accepted values are 51
.Nm ( IPPROTO_AH ),
and 4
.Nm ( IPPROTO_IP ) .
One can also specify the symbolic names "esp", "ah", and "ip4",
case insensitive.
.It chain
Delete the whole SPI chain, otherwise delete only the SPI given.
.It dst2
The second IP destination address used by
.Nm group .
.It spi2
The second SPI used by
.Nm group .
.It proto2
The second security protocol used by
.Nm group .
It defaults to
.Nm IPPROTO_AH .
Other accepted values are 50
.Nm ( IPPROTO_ESP ),
and 4
.Nm ( IPPROTO_IP ) .
One can also specify the symbolic names "esp", "ah", and "ip4",
case insensitive.
.It addr
The source address, source network mask, destination address and destination
network mask against which packets need to match to use the specified
Security Association.
.It transport
The protocol number which packets need to match to use the specified
Security Association. By default the protocol number is not used for
matching. Instead of a number, a valid protocol name that appears in
.Xr protocols 5
can be used.
.It sport
The source port which packets have to match for the flow.
By default the source port is not used for matching.
Instead of a number, a valid service name that appears in
.Xr services 5
can be used.
.It dport
The destination port which packets have to match for the flow.
By default the source port is not used for matching.
Instead of a number, a valid service name that appears in
.Xr services 5
can be used.
.It local
The
.Nm flow
command also creates a flow which matches local packets. This is aquivalent
to using a source address of 0.0.0.0 and a source network mask of
255.255.255.0.
.It delete
Instead of creating a flow, an existing flow is deleted.
.El
.Sh EXAMPLE
Setup a SPI which uses new esp with 3des encryption and HMAC-SHA1
authentication:
.Bd -literal
ipsecadm -enc 3des -auth sha1 -spi 1001 -dst 169.20.12.2 -src 169.20.12.3
-key 638063806380638063806380638063806380638063806380 -authp 1234123412341234
.Ed
.Pp
Setup a SPI for authentication with old ah only:
.Bd -literal
ipsecadm old ah -auth md5 -spi 1001 -dst 169.20.12.2 -src 169.20.12.3
-key 12341234deadbeef
.Ed
.Sh SEE ALSO
.Xr services 5 ,
.Xr protocols 5 ,
.Xr netstat 1 ,
.Xr isakmpd 8 ,
.Xr ipsec 4 ,
.Xr vpn 8 ,
.Xr photurisd 8