gure 33-16. Ethernet interfaces in use on a server Network Designs When designing a network like this, make sure you work closely with your systems people. There are a lot of things to think about. Here's a short list: Every interface will need an IP address. In some server high-availability solutions, a third IP address will be needed for each VLAN. For example, Solaris IP Multipathing requires a virtual IP address on each VLAN in addition to one for each physical interface. Every IP address you assign may need a DNS entry (including virtual IP addresses). Which interface is primary? Does the server need a default gateway? If so, where does it go? Can the server support multiple defaults? How will this work? Web servers need a default gate- way that points to the Internet. This will require your management VLAN to have specific routes on the servers. How many physical network cards do you need in a server to support six Ethernet interfaces? Make sure you have enough. Extra interfaces are even better. Will the servers have both interfaces active in each VLAN, or just one? Some server high-availability solutions require the switches to be configured a certain way, while others require different configurations. Work this out in a lab before you build your network. Will your servers support remote Ethernet consoles? Will you need a dedicated network for this traffic? When figuring out your IP scheme, it's a good idea to make the last octet (or octets) the same for every interface on each server. In other words, if your upper network is 10.1.10.0/24, and your lower network is 10.1.20.0/24, make the last octet match for the server on each network. Thus, the upper IP address would be 10.1.10.10, and the lower IP address would be 10.1.20.10. Remember that you must assign an IP address for each interface, SO make the last octet match for each switch. Figure 33-17 shows how such an IP scheme might work. Small Networks Many small companies don't have the need for elaborate three-tiered networks. Maybe they have only one of