ipsec interview questions

• What is IPsec? …
• Can you explain how an IPsec VPN works? …
• What are the main components of IPsec VPNs? …
• How does the use of encryption and authentication contribute to network security? …
• Can you explain what a virtual private network (VPN) is?

IPSec Interview Questions and Answers || Top 20 IPSec Questions

How Diffie-Hellman works? Each side has a private key which is never passed and a Diffie-Hellman Key (Public Key used for encryption). When both sides want to do a key exchange they send their Public Key to each other. for example Side A get the Public Key of Side B, then using the RSA it creates a shared key which can only be opened on Side B with Side Bs Private Key So, even if somebody intercepts the shared key he will not be able to do reverse engineering to see it as only the private key of Side B will be able to open it.

What is the difference between Transport and Tunnel mode? Tunnel mode – Protects data in network-to-network or site-to-site scenarios. It encapsulates and protects the entire IP packet—the payload including the original IP header and a new IP header (protects the entire IP payload including user data). Transport mode – Protects data in host-to-host or end-to-end scenarios. In transport mode, IPsec protects the payload of the original IP datagram by excluding the IP header (only protects the upper-layer protocols of IP payload (user data)). IPSec protocols AH and ESP can operate in either transport mode and tunnel mode.

2. Thin client mode – It works at Layer 7 and is also known as port forwarding. Thin client mode provides remote access to TCP-based services such as Telnet, Secure Shell (SSH), Simple Mail Transfer Protocol (SMTP), Internet Message Access Protocol (IMAP) and Post Office Protocol (POP3) applications. Thin client is delivered via a Java applet that is dynamically downloaded from the SSL VPN appliance upon session establishment.

What is DMVPN? DMVPN allows IPSec VPN networks to better scale hub-to-spoke and spoke-to-spoke topologies optimizing the performance and reducing latency for communications between sites. It offers the following benefits: 1. It Optimizes network performance. 2. It Reduces router configuration on the hub. 3. Support for dynamic routing protocols running over the DMVPN tunnels. 4. Support for multicast traffic from hub to spokes. 5. The capability of establishing direct spoke-to-spoke IPsec tunnels for communication between sites without having the traffic to go through the hub.

What is Site to Site and Remote Access VPN? A site-to-site VPN allows offices in multiple locations to establish secure connections with each other over a public network such as the Internet. Remote Access VPN allows Remote users to connect to the Headquarters through a secure tunnel that is established over the Internet. The remote user is able to access internal, private web pages and perform various IP-based network tasks. There are two primary methods of deploying Remote Access VPN: 1. Remote Access IPSec VPN. 2. Remote Access Secure Sockets Layer (SSL) VPN.

A user connects to the internet using DSL broadband from his laptop. After browsing certain pages, the user connects to the corporate network using the ipsec vpn client installed on the laptop. After connection is successful, the user is unable to browse internet. But on disconnecting the vpn client, the internet resumes. What could be the cause?

ESP and AH include the sequence number fields in the respective headers. The values are used by the IPSEC peers to track duplicate packets. If a packet with an already received sequence number arrives, it would be rejected, thus providing replay protection.

Which type of VPN would you use if data has to be encrypted at the network layer

a) ipsec does not support http ( browsing ) b) proxy is not enabled for the browser after ipsec client is connected c) default route is modified on the local PC d) This is the expected behavior, and cannot be resolved

UDP port 500 for IKE traffic, UDP port 1701 for L2TP communication between client and server and UDP port 4500 for NAT-T communication.

Name the security services VPN provides?

There are two types of VPN.

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FAQ

What are the 3 main protocols that IPsec uses?

Is IPsec a TCP or UDP?

What is IPsec and how it works?

1. Step 1: Defining Interesting Traffic. …
2. Step 2: IKE Phase One. …
3. Step 3: IKE Phase Two. …
4. Step 4: IPSec Encrypted Tunnel. …
5. Step 5: Tunnel Termination.