Networking Tips Tricks

When the DHCP Server role is installed on a domain controller, the DHCP Server inherits the security permissions of the domain controller. To prevent possible misuse of the domain controller’s elevated permissions, DHCP Servers that are installed on Windows Server 2003 do not register DNS records on behalf of the clients that are associated with the DHCP Server unless the DHCP Server is explicitly configured with DNS credentials. This behavior prevents a potential escalation of privilege to clients of the DHCP Server. Configuring DNS credentials on a DHCP Server that is running Windows Server 2003 Follow these steps to configure the DNS credentials of a DHCP Server that is installed on a domain controller running the Windows Server 2003 operating system: Start the DHCP management console. Click Start , then click Run and type dhcpmgmt.msc . In the DHCP navigation pane, expand the server node and right-click IPv4 , and then click Properties . In...

I’ve been trying to compile ISC DHCP 4.1 and to get it installed on a Solaris 10 u6 (11/08) zone for a few days. Compiling ISC DHCP is a simpler, as long as you are using gcc and not Solaris cc The issues have arisen when it has come to run ISC DHCP in a Solaris 10 zone . Read further to know more about setting a Solaris Container SunCluster resource to run ISC DHCP in a zone! ...

When DHCP servers are allocating IP addresses to the clients on the LAN, DHCP snooping can be configured on LAN switches to harden the security on the LAN to only allow clients with specific IP/MAC addresses to have access to the network.   DHCP snooping is a series of layer 2 techniques. It works with information from a DHCP server to:           * Track the physical location of hosts.           * Ensure that hosts only use the IP addresses assigned to them.           * Ensure that only authorized DHCP servers are accessible.   In short, DHCP snooping ensures IP integrity on a Layer 2 switched domain.   With DHCP snooping, only a whitelist of IP addresses may access the network. The whitelist is configured at   the switch port level, and the DHCP server manages the access control.   Only specific IP addresses with specific MAC addresses on specific ports may access the IP network.   ...

In part one of this article series on DHCP we went over a lot of the theory on the protocol itself. Specifically what types of messages there are, how DHCP works, and why it is normally used. In this last part we will look at two DHCP packets that exemplify what DHCP is all about. If you missed part one of this article series please read Understanding the DHCP Protocol (Part 1) . DHCP and you Part II In part one of this article series on DHCP we have seen that this protocol is typically enabled on most networks. This greatly eases the workload of the network administrator as DHCP will provide clients with key configuration details. Details such as what its IP address will be, the subnet mask, and the DNS servers it should use. Rather important information if you want to be able to access the Internet. Furthermore, we covered some of the various DHCP message types that you could encounter on a network. Well in this part of the article series we will actually look at two of the more comm...

DHCP is a little thought of protocol by many everyday computer users. Little do they know, though, that it plays a key role in the setup of their computer and how it is able to communicate. We shall explore its features and functionality within the confines of this two part article series. f you would like to read the second part of this series please read Understanding the DHCP Protocol (Part 2) . DHCP and you For many of the normal computer users out there today very little attention is paid to exactly how their computer goes about its business. This does not only include how your computer builds packets to convey information, but also how it initially gets the required information to set itself up to communicate. To whit, information such as its IP address, the DNS servers it will use, the DNS servers to use, amongst other critical details that your computer needs for it to access the Internet. Well what exactly is DHCP or as it is commonly known as; Dynamic Host Configuration Proto...

How to install and configure DHCP Server in Windows Server 2008 to provide IP addressing and DNS server information to your end users. Introduction Dynamic Host Configuration Protocol (DHCP) is a core infrastructure service on any network that provides IP addressing and DNS server information to PC clients and any other device. DHCP is used so that you do not have to statically assign IP addresses to every device on your network and manage the issues that static IP addressing can create. More and more, DHCP is being expanded to fit into new network services like the Windows Health Service and Network Access Protection (NAP). However, before you can use it for more advanced services, you need to first install it and configure the basics. Let’s learn how to do that. Installing Windows Server 2008 DHCP Server Installing Windows Server 2008 DCHP Server is easy. DHCP Server is now a “role” of Windows Server 2008 – not a windows component as it was in the past.

One of the most basic processes on a network is that of assigning IP addresses to network clients. Although there are many different types of DHCP servers that can do the job, you can configure Windows Server 2003 to act as a DHCP server. In this article, I will show you how. Years ago, I used to be a network administrator for an organization that had some rather odd security policies in place. One of the existing policies when I got there was that all computers had to be assigned a static IP address. DHCP servers were forbidden for security reasons. The result was a maintenance nightmare. Obviously, some servers have a legitimate need for static IP addresses, but usually it is perfectly acceptable for workstations to use dynamic IP addresses. Generally speaking, using static IP addresses on workstations is only truly feasible on small networks. Unfortunately, the network that I spoke of a moment ago was anything but small. It had 25,000 workstations.

"Dynamic Host Configuration Protocol (DHCP) is an IP standard designed to reduce the complexity of administering IP address configurations." - Microsoft's definition. A DHCP server would be set up with the appropriate settings for a given network. Such settings would include a set of fundamental parameters such as the gateway, DNS, subnet masks, and a range of IP addresses. Using DHCP on a network means administrators don't need to configure these settings individually for each client on the network. The DHCP would automatically distribute them to the clients itself. The DHCP server assigns a client an IP address taken from a predefined scope for a given amount of time. If an IP address is required for longer than the lease has been set for, the client must request an extension before the lease expires. If the client has not requested an extension on the lease time, the IP address will be considered free and can be assigned to another client. If the user wishes t...

Technical details Schema of a typical DHCP session DHCP uses the same two IANA assigned ports as BOOTP: 67/udp for the server side, and 68/udp for the client side. DHCP operations fall into four basic phases. These phases are IP lease request, IP lease offer, IP lease selection, and IP lease acknowledgement. After the client obtained an IP address, the client may start an address resolution query to prevent IP conflicts caused by address poll overlapping of DHCP servers. DHCP discovery The client broadcasts on the local physical subnet to find available servers. Network administrators can configure a local router to forward DHCP packets to a DHCP server on a different subnet. This client-implementation creates a UDP packet with the broadcast destination of 255.255.255.255 or subnet broadcast address. A client can also request its last-known IP address (in the example below, 192.168.1.100). If the client is still in a network where this IP is valid, the server might grant the request. O...