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Administrative Distance Cheat Sheet

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admin-distance-cheat

As a supplement to my video tutorial on Administrative Distance I have put together this AD Cheat Sheet to refer back to.

Remember, Admin Distance is a value attributed to a routing protocol to rank its trustworthiness. The more trustworthy a protocol is – lower AD is more ‘trusted’ – the more likely its routes will make it into the routing table. 

Please note, these are the default values. The administrative distance value can easily be amended by a network engineer at either the protocol level or at the route level. 

Route learned via:Admin Distance (Default)
Connected0
Static1
eBGP20
EIGRP90
OSPF110
IS-IS115
RIP120
EIGRP (External)170
iBGP200

This cheat sheet is for Cisco devices. Administrative Distance is not a “standard”, so each network vendor is completely free to use their own default values if they desire. For example, Juniper uses an AD of 170 for BGP routes, which can be confusing if you’re from a Cisco background; as you might think your Juniper router was running EIGRP!