Lab Notes - Misc 9.22.2010

Well I am trying to catch up to my ever growing stack of notes that I have made so I will just be adding stuff without any real thought of organization. I will note that since I have gotten my own real hardware, things have become much easier to learn as I am able to stop and start when I like and be able to do all of the required tasks!

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UDLD Note:

UDLD - Uses layer a 2 protocol to echo frames between the switches in which it is configured on to verify the ability to Tx / Rx.

Note: On the lab, should they ask "Provide Link Integrity" they are looking for UDLD.

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DAI Note & Small Configuration:

DAI - Dynamic Arp Inspection

Here is a small snippet on how to configure DAI:

arp access-list oscar
permit ip 172.16.1.10 0.0.0.0 mac 1111.2222.2222 0.0.0

SW1(config)#ip arp inspection

SW1(config)#ip arp inspection filter oscar vlan 500 static

SW1(config)#ip arp inspection validate src-mac ip

Here is a show command to verify results:

SW1(config)#do sh ip arp ins vla 500

Source Mac Validation      : Enabled
Destination Mac Validation : Disabled
IP Address Validation      : Enabled

 Vlan     Configuration    Operation   ACL Match          Static ACL
 ----     -------------    ---------   ---------          ----------
  500     Enabled          Active      oscar              Yes

 Vlan     ACL Logging      DHCP Logging      Probe Logging
 ----     -----------      ------------      -------------
  500     Deny             Deny              Off

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PBR Note & Small Configuration:

If your lab should mention that it is looking for a next-hop of last resort, it is probably looking for PBR (Policy Based Routing)

Here is an example:

Route-Map Out_R4
set ip default next-hop 172.16.1.1

ip local policy Out_R4

Note: If there is not a longer match in the router's RIB, then this can be used as a way to provide next hop redundancy.

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Spanning-Tree Note:

When trying to manipulate the path when there are multiple connections to multiple switches, "Cost" is evaluated before Priority. Just remember that "Priority" is used on the Root Switch and "Cost" is used on the Non-Root Switch.

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BGP Note:

When you are configuring BGP and using Advertise Maps / Non-Exist Maps, you must use an ACL (Do not use Prefix-List) to match your routes.

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OSPF Note:

If you have multiple ABR routers and these routers connect to NSSA's, then the router with the highest router-id will do the Type7-5 translations.

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IPv6 Redistribution:

Redistribution for IPv6 is different that IPv4 because you have to specifically redistribute connected, even if there part of the IGP.

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Split Horizon for IPv6 is enabled / disabled under the ipv6 router command:

#ipv6 router rip oscar

#no split-horizon

Keep in mind that when you are working with IPv6 that you will be leaving off the "ip" portion as that is considered IPv4.


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BVI - Bridged Virtual Interfaces

If you are using the same BVI on "one" interface, remember there might be an issue with split-horizon. Keep that in mind if only one router on the subnet is getting routes and the other is not.

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