Chapter Review

This chapter looked at how VPNs can be used to extend the corporate networks securely using public networks, such as the Internet. The two basic VPN types are remote access and site-to-site. The three types of VPN connectivity are access VPN, intranet VPN, and extranet VPN. The two VPN modes are transport and tunnel.

While a variety of Layer 2 and Layer 7 VPN implementations exist, IPSec and IETF Layer 3 standards seem to dominate the market today. IPSec technologies include a variety of authentication and encryption methods.

Questions

1.?	Which is not one of the three basic types of VPN connections? Access VPNs Intranet VPNs Internet VPNs Extranet VPNs
2.?	Which is not one of the concerns in using the Internet for conducting private communications? Loss of privacy High cost Loss of data integrity Identity spoofing
3.?	Which one of the following is a Layer 2 tunneling protocol supported by Microsoft and Cisco? PPTP L2F L2TP GRE
4.?	With which security protocol is the data not encrypted? AH EST ESP Diffie-Hellman
5.?	What is the size of the encryption key for DES? 40 bit 56 bit 128 bit 168 bit
6.?	Which one of the following is not an encryption algorithm? DES 3DES ESP AES
7.?	Which is the most secure hashing algorithm? MD5 SHA-1 HMAC MD5 HMAC SHA-1
8.?	With which security mode is the original IP header encrypted? AH Transport AH Tunnel ESP Transport ESP Tunnel
9.?	Which is not a valid transform? ah-md5-hmac esp-rfc1829 ah-des esp-sha-hmac
10.?	Transform sets can contain how many AH transforms? 1 2 3 None
11.?	Which cryptography type is also called public key encryption? Symmetric encryption Asymmetric encryption Hash function Cipher text
12.?	Which Diffie-Hellman key exchange offers the most security? 5 2 1 0
13.?	In an IPSec session, what is the minimum number of SAs that will be created? 1 2 3 6
14.?	At what point are the IPSec peers authenticated? IKE Phase One IKE Phase Two IKE Phase Three Interesting Traffic
15.?	What is a nonce? A large prime number A random number A pseudorandom number A digital signature

Answers

1.?	C. Internet VPNs
2.?	B. High cost
3.?	C. L2TP
4.?	A. AH
5.?	B. 56 bit
6.?	C. ESP
7.?	D. HMAC SHA-1
8.?	D. ESP Tunnel
9.?	C. ah-des
10.?	A. 1
11.?	B. Asymmetric encryption
12.?	A. 5
13.?	C. 3—1 IKE and 1 in each direction for IPSec
14.?	A. IKE Phase One
15.?	C. pseudorandom number