Internet Enhanced Services
7750 SR OS Services Guide Page 735
Description This command enables local proxy ARP. When local proxy ARP is enabled on an IP interface, the 
system responds to all ARP requests for IP addresses belonging to the subnet with its own MAC 
address, and thus will become the forwarding point for all traffic between hosts in that subnet.
When local-proxy-arp is enabled, ICMP redirects on the ports associated with the service are 
automatically blocked.  
Default ies>interface: no local-proxy-arp
ies>sub-if>grp-if: local-proxy-arp
ip-mtu
Syntax ip-mtu octets
no ip-mtu
Context config>service>ies>interface
Description This command configures the IP maximum transmit unit (packet) for this interface.
The no form of the command returns the default value.
Default no ip-mtu
loopback
Syntax [no] loopback
Context config>service>ies>interface
Description This command specifies that the associated interface is a loopback interface that has no associated 
physical interface.  As a result, the associated IES interface cannot be bound to a SAP.
Note that you can configure an IES interface as a loopback interface by issuing the loopback 
command instead of the sap sap-id command. The loopback flag cannot be set on an interface where 
a SAP is already defined and a SAP cannot be defined on a loopback interface.
Default none
mac
Syntax mac ieee-address
no mac
Context config>service>ies>interface
config>service>ies>sub-if>grp-if
Description This command assigns a specific MAC address to an IES IP interface.
For Routed Central Office (CO), a group interface has no IP address explicitly configured but inherits 
an address from the parent subscriber interface when needed. For example, a MAC will respond to an 
ARP request when an ARP is requested for one of the IPs associated with the subscriber interface 
through the group interface.