IP Global Parameters

The following table lists the IP global parameters, their default values, and where to find configuration information.

Table 1. IP global parameters
Parameter	Description	Default
IP state	The Internet Protocol, version 4	Enabled Note: You cannot disable IP.
Router ID	The value that routers use to identify themselves to other routers when exchanging route information. OSPF and BGP4 use router IDs to identify routers.	The IP address configured on the lowest-numbered loopback interface. If no loopback interface is configured, then the lowest-numbered IP address configured on the device.
IP Maximum Transmission Unit (MTU)	The maximum length an Ethernet packet can be without being fragmented.	1500 bytes for Ethernet II encapsulation
Address Resolution Protocol (ARP)	A standard IP mechanism that routers use to learn the Media Access Control (MAC) address of a device on the network. The router sends the IP address of a device in the ARP request and receives the device‘s MAC address in an ARP reply.	Enabled
ARP rate limiting	The maximum number of ARP packets that the device will accept each second. If the device receives more ARP packets than you specify, the device drops the extra ARP packets for the remainder of the one-second interval.	Disabled
ARP age	The maximum time that the device keeps a MAC address in its ARP cache. The device resets the timer to zero when the ARP entry is refreshed and removes the entry if the timer reaches the ARP age. Note: You can change the ARP age for an individual interface. See IP Interface Parameters.	25 minutes
Proxy ARP	An IP mechanism a router can use to answer an ARP request on behalf of a host, by replying with the router‘s own MAC address instead of the host‘s.	Enabled
Static ARP entries	An ARP entry that you place in the static ARP table. Static entries do not age out.	No entries
Time to Live (TTL)	The maximum number of routers (hops) through which a packet can pass before being discarded. Each router decreases a packet‘s TTL by 1 before forwarding the packet. If decreasing the TTL causes the TTL to be 0, the router drops the packet instead of forwarding it.	64 hops
Directed broadcast forwarding	A directed broadcast is a packet containing all ones (or in some cases, all zeros) in the host portion of the destination IP address. When a router forwards such a broadcast, it sends a copy of the packet out each of its enabled IP interfaces. Note: You can configure this parameter for an individual interface. See IP Interface Parameters.	Disabled
Source-routed packet forwarding	A source-routed packet contains a list of IP addresses through which the packet must pass to reach its destination.	Enabled
Internet Control Message Protocol (ICMP) messages	The Extreme device can send the following types of ICMP messages: Echo messages (ping messages) Destination Unreachable messages Redirect messages Note: You can configure ICMP Redirect messages for an individual interface. See IP Interface Parameters.	Enabled
Maximum DHCP relay hops	The maximum number of hops away a BootP server can be located from a router and still be used by the router‘s clients for network booting.	Four
Domain name for Domain Name Server (DNS) resolver	A domain name (example: extreme.router.com) you can use in place of an IP address for certain operations such as IP pings, trace routes, and Telnet management connections to the device.	None configured
DNS default gateway addresses	A list of gateways attached to the device through which clients attached to the device can reach DNS.	None configured
IP load sharing	A feature that enables the device to balance traffic to a specific destination across multiple equal-cost paths. Load sharing is based on a combination of destination MAC address, source MAC address, destination IP address, source IP address, and IP protocol. Note: Load sharing is sometimes called Equal Cost Multi Path (ECMP).	Enabled
Maximum IP load sharing paths	The maximum number of equal-cost paths across which this device is allowed to distribute traffic.	64
Origination of default routes	You can enable a device to originate default routes for the following route exchange protocols, on an individual protocol basis: OSPF BGP4 IS-IS	Disabled
Static route	An IP route that you place in the IP route table.	No entries
Source interface	The IP address the device uses as the source address for Telnet, RADIUS, or TACACS/TACACS+ packets originated by the device. The device can select the source address based on either of the following: The lowest-numbered IP address on the interface the packet is sent on. The lowest-numbered IP address on a specific interface. The address is used as the source for all packets of the specified type regardless of interface the packet is sent on.	The lowest-numbered IP address on the interface the packet is sent on.