Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

IP Proxy ARP !!!

Can anyone tell me what the belo mentioned command exactly refers to....

cisco(config) #no ip proxy arp

1 ACCEPTED SOLUTION

Accepted Solutions
Hall of Fame Super Silver

Re: IP Proxy ARP !!!

Hello Santhosh,

the command

no ip proxy-arp

in interface configuration mode disables the proxy ARP feature described in RFC 1027.

When Proxy ARP is enabled on a router interface the router replies to ARP requests for IP addresses that are not in the IP subnet associated to the interface if the router has a route to them ( including a default route),

This feature allows a router to assist an host that is missing the configuration of a default gateway or it has a wrong subnet mask.

The price to pay is an increased ARP activity as the assisted host instead of doing a single ARP request for the default gateway performs an ARP request for whatever IP address it needs to talk with

The answer to all these ARP requests is the same an ARP reply containing the router interface MAC address.

In this way the assisted host is able to send traffic to the router even if it is missing a default gateway in its TCP/IP stack configuration.

see the doc

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080094adb.shtml

For security reasons proxy ARP disabling is recommended

Hope to help

Giuseppe

2 REPLIES
Hall of Fame Super Silver

Re: IP Proxy ARP !!!

Hello Santhosh,

the command

no ip proxy-arp

in interface configuration mode disables the proxy ARP feature described in RFC 1027.

When Proxy ARP is enabled on a router interface the router replies to ARP requests for IP addresses that are not in the IP subnet associated to the interface if the router has a route to them ( including a default route),

This feature allows a router to assist an host that is missing the configuration of a default gateway or it has a wrong subnet mask.

The price to pay is an increased ARP activity as the assisted host instead of doing a single ARP request for the default gateway performs an ARP request for whatever IP address it needs to talk with

The answer to all these ARP requests is the same an ARP reply containing the router interface MAC address.

In this way the assisted host is able to send traffic to the router even if it is missing a default gateway in its TCP/IP stack configuration.

see the doc

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080094adb.shtml

For security reasons proxy ARP disabling is recommended

Hope to help

Giuseppe

New Member

IP Proxy ARP !!!

thank you for your kind & clear response guiseppe.

Regards,

Santhosh

405
Views
5
Helpful
2
Replies
CreatePlease login to create content