# References

For information about IPSec, see the following RFCs:

- RFC 768—User Datagram Protocol (August 1980)
- RFC 2401—Security Architecture for the Internet Protocol (November 1998)
- RFC 2402—IP Authentication Header (November 1998)
- RFC 2403—The Use of HMAC-MD5-96 within ESP and AH (November 1998)
- RFC 2404—The Use of HMAC-SHA-1-96 within ESP and AH (November 1998)
- RFC 2405—The ESP DES-CBC Cipher Algorithm With Explicit IV (November 1998)
- RFC 2406—IP Encapsulating Security Payload (ESP) (November 1998)
- RFC 2407—The Internet IP Security Domain of Interpretation for ISAKMP (November 1998)
- RFC 2408—Internet Security Association and Key Management Protocol (ISAKMP) (November 1998)
- RFC 2409—The Internet Key Exchange (IKE) (November 1998)
- RFC 2410—The NULL Encryption Algorithm and Its Use With IPSec (November 1998)
- RFC 3706—A Traffic-Based Method of Detecting Dead Internet Key Exchange (IKE) Peers (February 2004)

For information about using digital certificates, see Configuring Digital Certificates.