Enterasys Networks CSX6000, CSX5500, CSX7000 manual Proxy ARP

USER’S GUIDE

PROXY ARP

Use the following graphic to help you in verifying that Proxy ARP is operational. When following the verification steps, substitute your addresses for the addresses used in the example.

ISDN

CSX5500

"Site1"

128.168.1.x

CSX1200

"Site2"

128.168.2.x

Host A: 128.168.1.2 Host B: 128.168.2.2

1.Create two Ethernet LANs connected across the WAN with a CyberSWITCH and a second Cabletron platform (for example, another CyberSWITCH product) properly configured. The two Ethernet segments should be subnets of the same IP network. All IP host devices on the Ethernet segments (except the CyberSWITCH and the other Cabletron platform) should be configured with the natural subnet mask so that both Ethernet segments look like one IP network to all the IP host devices on the segments.

2.Try to have an IP host device on one Ethernet segment communicate with an IP host device on the other Ethernet segment. For example, ping from Host A to Host B.

3.If the communication between two IP devices across the WAN is successfully established, then the proxy ARP feature is properly working.

4.If the communication can NOT be established, display the ARP cache on the IP host devices to see what MAC addresses are mapped to the target IP address. On many operating systems, the arp -acommand displays the ARP cache. If the target IP addresses are mapped into the nearest CyberSWITCH’s MAC addresses respectively, for example, on Host A, Host B’s IP address is mapped to the CyberSWITCH A’s MAC address, then the proxy ARP feature is working properly, but basic IP routing may not be operational. Establish the basic IP connectivity first, then try to use the proxy ARP feature. If the target IP addresses are not shown (or are mapped to MAC addresses that are not displayed), try the following:

a.On both CyberSWITCH platforms, issue the ipnetif manage mode command to make sure that the proxy ARP feature is enabled for the LAN interface. If it is not enabled on one or both of the CyberSWITCH platforms, enable it through the CFGEDIT configuration utility. Note that you have to restart the system for the changes to be effective.

b.On both platforms, issue the ipnetif manage mode command to make sure the LAN interfaces are configured with the proper subnet mask. Configure these platforms with the proper subnet masks, not the natural masks.

472 CyberSWITCH