Configuring the DSL Router
3-5
6371-A2-GB20-10
August 2000
Address Resolution Protocol (ARP)
Address Resolution Protocol, as specified in RFC 826, is supported in the DSL
router. The DSL router provides for a total of 265 ARP table entries. The timeout
for completed and uncompleted ARP table entries is configurable.
NOTE:
The DSL router does not process ARP requests and ARP responses on its
DSL interface when it is configured to support RFC 1483 PDU routing
(Standard mode). See
Routed vs. Bridged PDUs
on page 3-10 for more
information. The operating mode (Standard or VNET) can be changed from
the DSL card without requiring any reconfiguration of the DSL router. If any
static ARP entries have been configured, they will remain in the database
and can be displayed with the show arp command. You can create static
ARP entries regardless of the current operating mode.
The Command Line Interface provides the ability to:
H Create up to 64 static ARP table entries to be retained across power cycles.
H Display the ARP table.
H Delete ARP table entries.
H Display and delete automatically added static ARP table entries by the DHCP
server and relay functions. Refer to
Dynamic Host Configuration Protocol
(DHCP) Server
on page 3-7.
Proxy ARP
The DSL router supports Proxy ARP. Proxy ARP responses are based on the IP
Routing table contents. The IP Routing table must have an entry for every host
that is reachable on the Ethernet interface, including hosts for which the DSL
router will not forward packets because of IP filters. If an ARP request is received
on one interface for an IP address that is reachable on the other interface, the
DSL router will respond with its own MAC address.
NOTE:
The Proxy ARP option is not available on the DSL interface when the DSL
router is configured to support RFC 1483 PDU routing. See
Routed vs.
Bridged PDUs
on page 3-10 for more information.
The Command Line Interface provides the ability to enable and disable Proxy
ARP for each interface.
NOTES:
— When Basic NAT is enabled, the DSL interface (dsl1) must have Proxy
ARP enabled if the dsl1 interface address is part of the Basic NAT global
IP network address.
— Proxy ARP and NAPT cannot be enabled at the same time.
