Concept Guide

Internet Protocol Security (IPSec)
Internet protocol security (IPSec) is an end-to-end security scheme for protecting IP communications by authenticating and encrypting all
packets in a communication session. Use IPSec between hosts, between gateways, or between hosts and gateways.
IPSec is compatible with Telnet and FTP protocols. It supports two operational modes: Transport and Tunnel.
• Transport mode — (default) Use to encrypt only the payload of the packet. Routing information is unchanged.
• Tunnel mode — Use to encrypt the entire packet including the routing information of the IP header. Typically used when creating virtual
private networks (VPNs).
NOTE: The Dell EMC Networking OS supports IPSec only for FTP and telnet protocols (ports 20, 21, and 23). The system rejects
if you congure IPSec for other protocols.
IPSec uses the following protocols:
• Authentication Headers (AH) — Disconnected integrity and origin authentication for IP packets
• Encapsulating Security Payload (ESP) — Condentiality, authentication, and data integrity for IP packets
• Security Associations (SA) — Necessary algorithmic parameters for AH and ESP functionality
IPSec supports the following authentication and encryption algorithms:
• Authentication only:
– MD5
– SHA1
• Encryption only:
– 3DES
– CBC
– DES
• ESP Authentication and Encryption:
– MD5 & 3DES
– MD5 & CBC
– MD5 & DES
– SHA1 & 3DES
– SHA1 & CBC
– SHA1 & DES
Conguring IPSec
The following sample conguration shows how to congure FTP and telnet for IPSec.
1 Dene the transform set.
CONFIGURATION mode
crypto ipsec transform-set myXform-seta esp-authentication md5 esp-encryption des
2 Dene the crypto policy.
CONFIGURATION mode
crypto ipsec policy myCryptoPolicy 10 ipsec-manual
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