Chapter 3 - MCSA/MCSE 70-291: The Dynamic Host Configuration Protocol

Chapter 3 - Developing the Network Services Design

Proposes a technique that realizes the interoperability between the Dynamic Host Configuration Protocol (DHCP) and the Domain Name System (DNS) over the TCP/IP network. Through an analysis of the IP (Internet Protocol) autoconfiguration mechanism provided by DHCP, the proposal requires only minor protocol extensions, which include updating the DHCP server mechanism and a DNS server designed to support queries of a dynamically configured database. Additionally, we define new message primitives (using DNS messages) to communicate with these servers. Designing an interoperable DHCP-DNS specification provides an advantage that maintains consistency between the host name and the actual IP address allocated by the DHCP server. Thus, it prevents a specific host from leading to confusion by dynamically allocating the DHCP when it communicates with other mobile hosts.

CHAPTER 8 - Installing, Configuring as a Server

3 - Installing Remote Installation Services Server

Dynamic Host Configuration Protocol (DHCP) starvation is an insider attack which prevents legitimate DHCP clients from acquiring network configuration parameters from DHCP server. The classical methods of creating starvation attack has a practical difficulty in wireless networks where an Access Point (AP) mandates a client to associate with unique MAC address before it can transmit such requests. This limits the effectiveness of starvation in wireless networks. In this paper, we describe a new method of creating starvation which is effective in both wired and wireless networks. This new method exploits a precautionary probing done by a DHCP server as described in RFC 2131. This probing verifies the to be offered IP address for accidental usage by other clients in the network. We show that a malicious insider can just send spoofed replies to these probes to create the effect of starvation in both wired and wireless networks.

In an IP-based network, automated dynamic assignment of IP addresses is preferable. In most wired networks, a node relies on a centralized server by using dynamic host configuration protocol (DHCP) to obtain a dynamic IP address. However, the DHCP-based approach cannot be employed in a mobile ad hoc network (MANET) due to the uncertainty of any centralized DHCP server. That is, a MANET may become partitioned due to host mobility. Therefore, there is no guarantee to access a DHCP server. A general approach to address this issue is to allow a mobile host to pick a tentative address randomly, and then use duplicate address resolution (DAR) protocol to resolve any duplicate addresses. In this paper, an innovative distributed dynamic host configuration protocol designed to configure nodes in MANET is presented. The proposed protocol not only can detect the duplicate address, but also can resolve the problem caused by duplicate address. It shows that the proposed protocol works correctly and is more universal than earlier approaches. An enhanced version of DAR scheme is also proposed in this paper to solve the situation of duplicate MAC address. The new and innovative approach proposed in this paper can make the nodes in MANET provide services to other networks and avoid packets from being delivered to incorrect destinations.

The Dynamic Host Configuration Protocol (DHCP) is used to effectively allocate IP addresses on a local area network. Despite the widespread usage of DHCP, few studies related to users exist on DHCP server logs, and even less is known about the user behavior and devices of a large-scale wireless local area network (WLAN). In this paper, we propose a methodology to feasibly analyse mobility and concentration of users and generally analyse the temporal distribution and the providers’ distribution of wireless devices. The method is not involved with user privacy and safety, and fully explores available DHCP metrics and logs. Our results show that individual users are more likely to concentrate in labs and classrooms on weekdays while they prefer to concentrate in their dormitory and library on the weekends. The online time of 80% of wireless devices is less than 10 hours and the provider Apple takes nearly 50% of all wireless devices according to the data set of T University. We except similar benefits to arise for analyzing large-scale WLAN and optimize DHCP.

Network security has become a concern with the rapid growth and expansion of the Internet. While there are several ways to provide security for communications at the application, transport, or network layers, the data link layer security has not yet been adequately addressed. Dynamic Host Configuration Protocol (DHCP) and Address Resolution Protocol (ARP) are link layer protocols that are essential for network operation. They were designed without any security features. Therefore, they are vulnerable to a number of attacks such as the rogue DHCP server, DHCP starvation, host impersonation, man-in-the-middle, and denial of service attacks. Vulnerabilities in ARP and DHCP threaten the operation of any network. The existing solutions to secure ARP and DHCP could not mitigate DHCP starvation and host impersonation attacks. This work introduces a new solution to secure ARP and DHCP for preventing and mitigating these LAN attacks. The proposed solution provides integrity and authenticity for ARP and DHCP messages. Security properties and performance of the proposed schemes are investigated and compared to other related schemes.

A mobile ad hoc network (MANET) is a multi-hop wireless network capable of autonomous operation. The mobility of MANET nodes can lead to frequent and unpredictable topology changes. Most MANET literature assumes that network related information of a node (such as its IP address, netmask, etc.) is configured statically, prior to the node joining the MANET. However, not all nodes have IP addresses permanently assigned to them. Such nodes rely on a centralized server and use a dynamic host configuration protocol, like DHCP (dynamic host configuration protocol), to acquire an IP address. Such a solution cannot be employed in MANETs due to the unavailability of any centralized DHCP server. In this paper, we first present a survey of possible solutions approaches, and discuss their limitations. Then, we present a distributed dynamic host configuration protocol designed to configure nodes in a MANET. We show that the proposed protocol works correctly and does not have the limitations of earlier approaches. Finally, we evaluate the performance of the solution through simulation experiments, and conclude with a discussion of related security issues.

Chapter 11 - Managing Windows 2000 Network Services Fast Track

The DHCP (Dynamic Host Configuration Protocol) protocol is not only convenient for the network administrator to manage IP address and user to use IP address, but also solves some of the problems that the shortage of IPv4 address causes. With the development of information technology and network, the DHCP has been widely used. However, due to the protocol without security mechanism, the potential security vulnerabilities such as illegal DHCP, Mac address disguise, replay attack and DoS attack are becoming more and more prominent. Based on the OTP (One Time Password), a security authentication model that is called OTP_SAM is mainly proposed in this paper. The model combines with the current system time to compute the one-time key, and then use the key to generate the message authentication code by hash algorithm. Finally, the model achieves the objective of the security authentication through the verification of the authentication code in Option180. Experimentation indicates that OTP_SAM ensures the security characteristic, as well has higher efficiency.

The authors describe a connection-oriented transport-level protocol (local network transport protocol, LNTP) specifically designed for use on LANs (local area networks). The fundamental philosophy in the design of LNTP is simplicity. Features irrelevant to the LAN environment are not included, resulting in a simpler and more efficient protocol. LNTP uses a simple but effective two-region flow control mechanism which is activated only when the traffic intensity exceeds some value. This eliminates control packets during normal operation and increases concurrency between sender and receiver. LNTP runs under 4.2 BSD UNIX in place of TCP/IP (transmission control protocol/internet protocol). Detailed comparisons between LNTP and TCP/IP show that LNTP is several times faster, although end-to-end throughput rates are only 30% faster because of the overhead attributed to Ethernet and UNIX layers. However, the reduced CPU cycles as well as the increased network throughput indicate that LNTP is a viable replacement for TCP/IP. >

A MANET consists of a set of mobile nodes where mobile nodes have routing capabilities to forward packets. Each mobile host becomes a member of a self-organizing wireless network, where one another communicate over multi-hop wireless links, without relying on a fixed communication infrastructure, such as a base station or an access point. It is essential that all nodes are able to perform the operations required for the configuration of unique addresses to execute proper routing of data packets in a MANET. Address auto-configuration is an important issue, since address pre-configuration is not always possible in MANETs. MANETs currently depend on checking the IP addresses of nodes to decide if the connection and identification of nodes participating in a MANET are established. In conventional networks, address auto-configuration is categorized as either a stateless or a stateful protocol. When a network is not especially required to control the exact IP address assignments if the addresses are unique and routable, the stateless approach is used. In contrast, the stateful approach is used when a network demands exact IP address assignments. Dynamic host configuration protocol (DHCP) is an example of a stateful protocol, where a DHCP server assigns unique addresses to unconfigured nodes and keeps state address information in an address allocation table. However, in stateless protocols, a node can select an address and verify its uniqueness in a distributed manner using DAD algorithms. Using DAD algorithms, a node in a MANET, which lacks an IP address in the MANET, can determine if a candidate address it selects is available. A node already equipped with an IP address also depends on DAD to protect its IP address from being accidentally used by another node in the MANET. Based on the conventional method [1], DAD can be classified as Strong DAD and Weak DAD. Strong DAD uses an address discovery mechanism, where a node randomly selects an address and requests the address within a MANET, checking if the address is being used in the MANET. Based on a reply to the claimed request, which needs to arrive at the node within a finite bounded time interval, the node can detect address duplication in the MANET. Weak DAD is proposed, where ad hoc routing protocols are used to detect address duplication by modification of the routing protocol packet format. MANET routing

Traditionally wireline network and wireless network have been operated and managed separately. Future network will provide converged network service on wireline and wireless networks together. Service requirement for unified access to both wireline and wireless networks emerged as we experience more sophisticated network services. This paper discusses a unified access control for 5G convergence network with multiplicity of different access networks. With minor change onto Dynamic Host Configuration Protocol (DHCP) we can reuse authentication information among various access technologies on 5G convergence network. The proposed method enables us to reuse authentication information from one access network onto another access network. Authentication reuse and unified access control will reduce complexity of 5G convergence network access procedure with multiple access networks and provide consistent access procedure regardless what access technology a user chooses to use.

Chapter 2 - Microsoft TCP/IP 2000