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As you may have guessed by the question title I have a lot to learn about networking in general. That being said I am unsure why my ARP table does not show a recently pinged address, or if it is suppose to. After pinging cisco.com my ARP table shows the following:

(ARP command performed from my laptop running win7, this was not done on a switch or router)

Interface: 10.209.226.154 --- 0xc Internet Address Physical Address Type 10.209.226.1 00-00-0c-07-ac-e2 dynamic
10.209.226.21 9c-93-4e-28-ca-e8 dynamic
10.209.226.22 00-00-aa-ce-d5-20 dynamic
10.209.226.29 00-1a-4b-1d-d7-4a dynamic
10.209.226.59 2c-44-fd-62-7d-39 dynamic
10.209.226.69 d8-9d-67-98-92-b7 dynamic
10.209.226.71 a0-b3-cc-4b-8a-39 dynamic
10.209.226.99 00-1a-a0-6f-10-cd dynamic
10.209.226.133 18-a9-05-2a-da-a4 dynamic
10.209.226.161 78-e3-b5-cb-e8-65 dynamic
10.209.226.172 f0-92-1c-5c-a8-2b dynamic
10.209.226.192 00-21-70-9b-f8-aa dynamic
10.209.226.255 ff-ff-ff-ff-ff-ff static
224.0.0.2 01-00-5e-00-00-02 static
224.0.0.22 01-00-5e-00-00-16 static
224.0.0.251 01-00-5e-00-00-fb static
224.0.0.252 01-00-5e-00-00-fc static
239.192.83.80 01-00-5e-40-53-50 static
239.255.255.250 01-00-5e-7f-ff-fa static
239.255.255.253 01-00-5e-7f-ff-fd static
255.255.255.255 ff-ff-ff-ff-ff-ff static

Interface: 172.19.43.226 --- 0xd Internet Address Physical Address Type 172.19.32.1 00-00-0c-07-ac-20 dynamic
172.19.47.255 ff-ff-ff-ff-ff-ff static
224.0.0.2 01-00-5e-00-00-02 static
224.0.0.22 01-00-5e-00-00-16 static
224.0.0.251 01-00-5e-00-00-fb static
224.0.0.252 01-00-5e-00-00-fc static
239.255.255.250 01-00-5e-7f-ff-fa static
239.255.255.253 01-00-5e-7f-ff-fd static
255.255.255.255 ff-ff-ff-ff-ff-ff static

Here we see the rest of the devices on my LAN that I frequently communicate with and their corresponding MAC addresses. A series of devices are listed within the 10.209.226.0 subnet that appear to have been learned dynamically, meaning my device learned the MAC’s of these other devices by being told by the other devices. At the end of the list of devices in the 10.209.226.0 subnet the IP address changes to 224.0.0.2 which are all static, which would imply that these MAC address are programmed into the network devices on this particular subnet.

This is about as far as I have gotten in understanding the output. If anyone could help me understand why I dont see the cisco.com ping, I would appreciate as well.

Thanks in advance for any assistance.

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closed as off-topic by sciurus, pauska, joeqwerty, Cheekaleak, longneck Jan 10 at 19:26

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2  
You need to read more. ARP converts for example an IP address into an link layer (frequently Ethernet) address. Unless you are on the same link-layer as cisco.com you won't see it's link-layer address. –  Iain Jan 10 at 18:09

1 Answer 1

  1. MAC addresses don't transit routers. You will never see the MAC address of a host that is not on the same subnet as your host.

  2. The 224 and 239 ip/MAC addresses are multicast addresses and it is perfectly normal to see them in your ARP table. For more info, see here - http://en.wikipedia.org/wiki/Multicast_address

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I thought as much. Thank you for your help –  user2124939 Jan 10 at 18:57

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