Content-type: text/html Manpage of IPSEC_SPI

IPSEC_SPI

Section: Maintenance Commands (8)
Updated: 21 Jun 2000
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NAME

ipsec spi - manage IPSEC Security Associations

SYNOPSIS

Note: In the following, <SA> means: --edst daddr --spi spi --proto proto OR --said said

ipsec spi

ipsec spi <SA> --ah hmac-md5-96|hmac-sha1-96 [ --replay_window replayw ] --authkey akey

ipsec spi <SA> --esp 3des --replay_window replayw ] --enckey ekey

ipsec spi <SA> --esp 3des-md5-96|3des-sha1-96 [ --replay_window replayw ] --enckey ekey --authkey akey

ipsec spi <SA> --esp null-md5-96|null-sha1-96 [ --replay_window replayw ] --authkey akey

ipsec spi <SA> --ip4 --src encap-src --dst encap-dst

ipsec spi <SA> --del

ipsec spi --help

ipsec spi --version

ipsec spi --clear

DESCRIPTION

Spi creates and deletes IPSEC Security Associations. A Security Association (SA) is a transform through which packet contents are to be processed before being forwarded. A transform can be an IP-in-IP encapsulation, an IPSEC Authentication Header (authentication with no encryption), or an IPSEC Encapsulation Security Payload (encryption, possibly including authentication).

When a packet is passed from a higher networking layer through an IPSEC virtual interface, a search in the extended routing table (see ipsec_eroute(8)) yields an effective destination address, a Security Parameters Index (SPI) and a IP protocol number. When an IPSEC packet arrives from the network, its ostensible destination, an SPI and an IP protocol specified by its outermost IPSEC header are used. The destination/SPI/protocol combination is used to select a relevant SA. (See ipsec_spigrp(8) for discussion of how multiple transforms are combined.)

The daddr, spi and proto arguments specify the SA to be created or deleted. Daddr is a dotted-decimal IPv4 destination address. Spi is a number, preceded by '0x' for hexadecimal, between 0x100 and 0xffffffff; values from 0x0 to 0xff are reserved. Proto is an ASCII string, "ah", "esp" or "tun", specifying the IP protocol. The protocol must agree with the algorithm selected.

Alternatively, the said argument can also specify an SA to be created or deleted. Said combines the three parameters above, such as: "tun0x101@1.2.3.4"

Keys vectors must be entered as hexadecimal or base64 numbers. They should be cryptographically strong random numbers.

All hexadecimal numbers are entered as strings of hexadecimal digits (0-9 and a-f), without spaces, preceded by '0x', where each hexadecimal digit represents 4 bits. All base64 numbers are entered as strings of base64 digits
(0-9, A-Z, a-z, '+' and '/'), without spaces, preceded by '0s', where each hexadecimal digit represents 6 bits and '=' is used for padding.

The deletion of an SA which has been grouped will result in the entire chain being deleted.

The form with no additional arguments lists the contents of /proc/net/ipsec_spi. The format of /proc/net/ipsec_spi is discussed in ipsec_spi(5).

OPTIONS

--edst: specifies the effective destination daddr of the Security Association
--spi: specifies the Security Parameters Index spi of the Security Association
--proto: specifies the IP protocol proto of the Security Association
--said: specifies the Security Association in monolithic format
--ah: add an SA for an IPSEC Authentication Header, specified by the following transform identifier (hmac-md5-96 or hmac-sha1-96) (RFC2402, obsoletes RFC1826)
hmac-md5-96: transform following the HMAC and MD5 standards, using a 128-bit key to produce a 96-bit authenticator (RFC2403)
hmac-sha1-96: transform following the HMAC and SHA1 standards, using a 160-bit key to produce a 96-bit authenticator (RFC2404)
--esp: add an SA for an IPSEC Encapsulation Security Payload, specified by the following transform identifier (3des, or 3des-md5-96) (RFC2406, obsoletes RFC1827)
3des: encryption transform following the Triple-DES standard in Cipher-Block-Chaining mode using a 64-bit iv (internally generated) and a 192-bit 3DES ekey (RFC2451)
3des-md5-96: encryption transform following the Triple-DES standard in Cipher-Block-Chaining mode with authentication provided by HMAC and MD5 (96-bit authenticator), using a 64-bit iv (internally generated), a 192-bit 3DES ekey and a 128-bit HMAC-MD5 akey (RFC2451, RFC2403)
3des-sha1-96: encryption transform following the Triple-DES standard in Cipher-Block-Chaining mode with authentication provided by HMAC and SHA1 (96-bit authenticator), using a 64-bit iv (internally generated), a 192-bit 3DES ekey and a 160-bit HMAC-SHA1 akey (RFC2451, RFC2404)
null-md5-96: encryption using the identity transform with authentication provided by HMAC and MD5 (96-bit authenticator), using a 128-bit HMAC-MD5 akey (RFC2410, RFC2403)
null-sha1-96: encryption using the identity transform with authentication provided by HMAC and SHA1 (96-bit authenticator), using a 160-bit HMAC-SHA1 akey (RFC2410, RFC2404)
--replay_window replayw: sets the replay window size; valid values are decimal, 1 to 64
--ip4: add an SA for an IP-in-IP tunnel from encap-src to encap-dst
--src: specify the source end of an IP-in-IP tunnel from encap-src to encap-dst
--dst: specify the destination end of an IP-in-IP tunnel from encap-src to encap-dst
--del: delete the specified SA
--clear: clears the table of SAs
--help: display synopsis
--version: display version information

EXAMPLES

To keep line lengths down and reduce clutter, some of the long keys in these examples have been abbreviated by replacing part of their text with ``...''. Keys used when the programs are actually run must, of course, be the full length required for the particular algorithm.

ipsec spi --edst gw2 --spi 0x125 --proto esp \
--esp 3des-md5-96 \
--enckey 0x6630...97ce \
--authkey 0x9941...71df

sets up an SA to gw2 with an SPI of 0x125 and protocol ESP (50) using 3DES encryption with integral MD5-96 authentication transform, using an encryption key of 0x6630...97ce and an authentication key of 0x9941...71df (see note above about abbreviated keys).

ipsec spi --said tun0x987@192.168.100.100 --del

deletes an SA to 192.168.100.100 with an SPI of 0x987 and protocol IPIP (4).

FILES

/proc/net/ipsec_spi, /usr/local/bin/ipsec

HISTORY

Written for the Linux FreeS/WAN project <http://www.freeswan.org/> by Richard Guy Briggs.

BUGS

The syntax is messy and the transform naming needs work.

This document was created by man2html, using the manual pages.
Time: 02:46:48 GMT, July 02, 2000