ipsecah(7P) Protocols ipsecah(7P)
NAME
ipsecah, AH - IPsec Authentication Header
SYNOPSIS
drv/ipsecah
DESCRIPTION
The ipsecah module (AH) provides strong integrity, authentication, and partial sequence integrity (replay protection) to IP datagrams. AH
protects the parts of the IP datagram that can be predicted by the sender as it will be received by the receiver. For example, the IP TTL
field is not a predictable field, and is not protected by AH.
AH is inserted between the IP header and the transport header. The transport header can be TCP, UDP, ICMP, or another IP header, if tun-
nels are being used. See tun(7M).
AH Device
AH is implemented as a module that is auto-pushed on top of IP. The entry /dev/ipsecah is used for tuning AH with ndd(1M).
Authentication Algorithms
Current authentication algorithms supported include HMAC-MD5 and HMAC-SHA-1. Each authentication algorithm has its own key size and key
format properties. You can obtain a list of authentication algorithms and their properties by using the ipsecalgs(1M) command. You can also
use the functions described in the getipsecalgbyname(3NSL) man page to retrieve the properties of algorithms.
Security Considerations
Without replay protection enabled, AH is vulnerable to replay attacks. AH does not protect against eavesdropping. Data protected with AH
can still be seen by an adversary.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsr |
|Interface Stability |Evolving |
+-----------------------------+-----------------------------+
SEE ALSO
ipsecalgs(1M), ipsecconf(1M), ndd(1M), attributes(5), getipsecalgbyname(3NSL), tun(7M), ip(7P), ipsec(7P), ipsecesp(7P)
Kent, S. and Atkinson, R.RFC 2402, IP Authentication Header, The Internet Society, 1998.
SunOS 5.11 20 May2003 ipsecah(7P)