BigIron RX Series Configuration Guide 15953-1001986-01Configuring IP parameters 7Configuring IP parametersSome parameters can be configured globally while others can be configured on individualinterfaces. Some parameters can be configured globally and overridden for individual interfaces.Configuring IP addressesYou can configure an IP address on the following types of the device interfaces:• Ethernet port• Virtual routing interface (also called a Virtual Ethernet or “VE”)• Loopback interfaceBy default, you can configure up to 24 IP addresses on each interface.Also, the CAM can hold up to 256,000 IP address entries.DHCP gateway stamp The router can assist DHCP/BootP Discovery packets from onesubnet to reach DHCP/BootP servers on a different subnet byplacing the IP address of the router interface that receives therequest in the request packet’s Gateway field.You can override the default and specify the IP address to use forthe Gateway field in the packets.NOTE: UDP broadcast forwarding for client DHCP/BootP requests(bootpc) must be enabled and you must configure an IPhelper address (the server’s IP address or a directedbroadcast to the server’s subnet) on the port connected tothe client.The lowest-numbered IPaddress on the interface thatreceives the requestpage 218UDP broadcastforwardingThe router can forward UDP broadcast packets for UDPapplications such as BootP. By forwarding the UDP broadcasts,the router enables clients on one subnet to find servers attachedto other subnets.NOTE: To completely enable a client’s UDP application request tofind a server on another subnet, you must configure an IPhelper address consisting of the server’s IP address or thedirected broadcast address for the subnet that containsthe server. See the next row.The router helps forwardbroadcasts for the followingUDP application protocols:• bootps• dns• netbios-dgm• netbios-ns• tacacs• tftp• timepage 215IP helper address The IP address of a UDP application server (such as a BootP orDHCP server) or a directed broadcast address. IP helperaddresses allow the router to forward requests for certain UDPapplications from a client on one subnet to a server on anothersubnet.None configured page 216a. Some devices have a factory default, such as 209.157.22.154, used for troubleshooting during installation. For thedevice, the address is on module 1 port 1 (or 1/1).TABLE 44 IP interface parameters (Continued)Parameter Description Default See page...
