filter default route

[mzouggagh]

I have static default route configured in L3out-01

I have multiple OSPF L3outs with  0.0.0.0/0 and both “Export Route Control Subnet” and “Aggregate Export” are enabled 

I need to filter default route when exporting route from one of the OSPF L3out.

what is the best option ? and how ?

[Remi-Astruc · Accepted solution]

Hi @mzouggagh ,

Nice to meet you there.

To filter out 0.0.0.0/0 you need to use 2 subnets 0.0.0.0/1 + 128.0.0.0/1 instead of a single 0.0.0.0/0, then create and associate 2 route-maps, 1 matching 0.0.0.0/1 with Aggregate, 1 matching 128.0.0.0/1 with Aggregate. Resulting match will be mask between 1 and 32.

Regards

[mzouggagh]

Hi @Remi-Astruc ,

Nice to meet you too.

so from l3out where I want to filter 0.0.0.0/0:
1) I delete 0.0.0.0/0 with “Export Route Control Subnet” and “Aggregate Export”  from L3out EPG
2) create default-export route map with  2 seq, 1 matching 0.0.0.0/1 with Aggregate, 1 matching 128.0.0.0/1 with Aggregate
correct ?

[Remi-Astruc]

Correct.

That assumes the other L3outs are set on different Border Leaves.

[mzouggagh]

Hi @Remi-Astruc 

Thanks, your recommendation is working. 
we tried an other method:
 1) 0.0.0.0/0 with “Export Route Control Subnet” and “Aggregate Export”  from L3out EPG
 2) created route control profile:
       - Match routing policy only
       - deny 0.0.0.0/0
       - permit all
Do you recommend this type of route map ? 

[Remi-Astruc]

Hi @mzouggagh ,

Could be.

Keep in mind that specific subnets definition is still a best practice with Export Route Control to avoid issues.

Regards