[c-nsp] IOS-XR accepted duplicate subnet configurations for interface

[adamv0025 at netconsultings.com]

> Christoffer Hansen
> Sent: Wednesday, September 26, 2018 10:47 PM
> 
> Dear c-nsp fellows,
> 
> I am not sure if any one of you would have an answer the the below
> example...
> 
> I have recently run into a case with an ASR9k router running IOS-XR v5.3.4.
> Were I by accident put an identical secondary subnet on a 2nd interface
> located inside the same VRF as the first one. It is even a 2nd sub-interface to
> another sub-interface on the same main interface.
> 
> Case-in-point: The router accepted the configuration commit without
> complaints and of course traffic then stops flowing.
> 
> Normally I would not expect this to be possible to do. And would expect the
> router to output a warning telling me I am trying to commit an IPv4
> address|subnet already configured on another interface in the same VRF.
> 
Hi,

Yes this is an unfortunate default in XR,
Hence you might want to configure the correct behaviour using:
ipv4 conflict-policy static
ipv6 conflict-policy static

adam

netconsultings.com
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