AD is a numeric value that specifies the preference of a particular route source# which range from 0 to 255. The lower the value, the more trust the Router will be on the source. The following table shows the AD value for each route source.
| Router Source | Default AD |
|---|---|
| Directly connected interface | 0 |
| Static route | 1 |
| EIGRP summary route | 5 |
| eBGP | 20 |
| EIGRP (internal) | 90 |
| IGRP | 100 |
| #Open Shortest Path First (OSPF) | 110 |
| #Intermediate System to Intermediate System (IS-IS) | 115 |
| #Routing Information Protocol (RIP) | 120 |
| EIGRP (external) | 170 |
| iBGP | 200 |
| Unknown | 255 |
In #Cisco Internetwork Operating System (IOS), it could be shown using the command show ip route and inspect the routing table. It is typically in the format of:
D 192.168.6.0/24 [120/1] via ...There first value in the square bracket shows the AD for the route, which is RIP. The second value in the bracket indicates the metric of the route.
A much robust way to show the AD value for each protocol is to run the command show ip protocols.