Archive for the Proxy Arp Command Category

Proxy Arp – who needs a gateway!!!!!!?

Posted in Proxy Arp Command on May 13, 2008 by itdaddy

 

Ever wondered why when you don’t have a gateway or you use the wrong one, you still get routing?  Well this maybe why! Proxy Arp is enabled on the gateway or routers.

Click on link to read PDF all about Proxy ARP command:

https://itdaddy.files.wordpress.com/2008/05/proxyarp.pdf

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Real life test using arp table

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To prove your gateway has Proxy Arp enabled, do this:

1. If your current subnet is /24 change your PC TCP/IP settings to /16

2. then ping a ip you know is on a different subnet. say 192.168.2.1

3. once you ping fire up command prmpt and type in “arp -a” should

see the same mac address ast your gateway as the mac for the 192.168.2.1

if so you are using Proxy ARP! yeah baby yeah!

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Here is my test with say a /16 vs /24 bit subnet using the pdf eample from cisco you gave me…

arp table on my pc is this(mock ip addresses not reall ones) but the same concept:

say i pinged server2 192.168.2.1
and i changed my subnet mask from 24 to 16
ping srv2 with using DNS server but arp shows this:

 
 Internet Address      Physical Address      Type
192.168.1.1           00-e0-18-04-96-af     dynamic
192.168.1.2           00-15-2b-e6-fe-41     dynamic  – gateway
192.168.1.10          00-30-48-60-37-2c     dynamic
192.168.1.13          00-00-74-d4-8a-95     dynamic
192.168.1.18          00-1b-fc-35-c0-73     dynamic
192.168.1.93          00-e0-81-2a-fa-d3     dynamic
192.168.2.1           00-15-2b-e6-fe-41     dynamic  – server 2 ip

 

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