Configuring IP

5.Enter a value from 0 – 240 into the ARP Age field.

6.Click the Apply button to save the change to the device’s running-config file.

7.Select the Save link at the bottom of the dialog. Select Yes when prompted to save the configuration change to the startup-config file on the device’s flash memory.

Enabling Proxy ARP

Proxy ARP allows a routing switch to answer ARP requests from devices on one network on behalf of devices in another network. Since ARP requests are MAC-layer broadcasts, they reach only the devices that are directly connected to the sender of the ARP request. Thus, ARP requests do not cross routers.

For example, if Proxy ARP is enabled on a routing switch connected to two sub-nets, 10.10.10.0/24 and 20.20.20.0/24, the routing switch can respond to an ARP request from 10.10.10.69 for the MAC address of the device with IP address 20.20.20.69. In standard ARP, a request from a device in the 10.10.10.0/24 sub-net cannot reach a device in the 20.20.20.0 sub-net if the sub-nets are on different network cables, and thus is not answered.

NOTE: An ARP request from one sub-net can reach another sub-net when both sub-nets are on the same physical segment (Ethernet cable), since MAC-layer broadcasts reach all the devices on the segment.

Proxy ARP is disabled by default on HP routing switches. The feature is not supported on the HP 6208M-SX.

To enable Proxy ARP, use either of the following methods.

USING THE CLI

To enable IP proxy ARP, enter the following command:

HP9300(config)# ip proxy-arp

To again disable IP proxy ARP, enter the following command:

HP9300(config)# no ip proxy-arp

Syntax: [no] ip proxy-arp

USING THE WEB MANAGEMENT INTERFACE

1.Log on to the device using a valid user name and password for read-write access. The System configuration panel is displayed.

2.Click on the plus sign next to Configure in the tree view to expand the list of configuration options.

3.Click on the plus sign next to IP in the tree view to expand the list of IP option links.

4.Click on the General link to display the IP configuration panel.

5.Select the Enable or Disable radio button next to Proxy ARP.

6.Click the Apply button to save the change to the device’s running-config file.

7.Select the Save link at the bottom of the dialog. Select Yes when prompted to save the configuration change to the startup-config file on the device’s flash memory.

Creating Static ARP Entries

HP routing switches have a static ARP table, in addition to the regular ARP cache. The static ARP table contains entries that you configure.

Static entries are useful in cases where you want to pre-configure an entry for a device that is not connected to the routing switch, or you want to prevent a particular entry from aging out. The software removes a dynamic entry from the ARP cache if the ARP aging interval expires before the entry is refreshed. Static entries do not age out, regardless of whether the HP device receives an ARP request from the device that has the entry’s address.

NOTE: You cannot create static ARP entries on a switch.

The maximum number of static ARP entries you can configure depends on the product. See “Changing the Maximum Number of Entries the Static ARP Table Can Hold” on page 6-31.

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