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use of longer-prefixes in show ip route command

I'm baffled why the url

shows network for instance

as a result of the command

Router# show ip route longer-prefixes

Hall of Fame Super Silver

Re: use of longer-prefixes in show ip route command


the text says

The following is sample output using the longer-prefixes keyword. When the longer-prefixes keyword is included, the address and mask pair becomes the prefix, and any address that matches that prefix is displayed. Therefore, multiple addresses are displayed.

In the following example, the logical AND operation is performed on the source address and the mask, resulting in Each destination in the routing table is also logically ANDed with the mask and compared to that result of Any destinations that fall into that range are displayed in the output.

I tried on my router and actually it shows prefixes despite the first byte value

if I use I see nothing for example.

if I use I see some routes only a few in comparison with

This command in this way doesn't look like immediate.

Hope to help


New Member

Re: use of longer-prefixes in show ip route command

thanks for reply Giuseppe

I can understand the command in circumstances say where you have a number of routes of longer prefixes to the network and mask listed


sh ip ro lo giving say

However I can't see how results from sh ip ro lo

It is also possible to use non-contiguous masks such as

sh ip ro lo

and get routes listed

Can you make any sense of it?

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