any dangers of filtering every /24 on full internet table to preserve FIB space ?

Jakob Heitz (jheitz) jheitz at
Thu Oct 13 02:05:34 UTC 2022

Here is a reason you might want to keep that /24.

Suppose you are a small ISP and I am your customer.
I also have another larger provider.
That larger provider is also your provider.
I own a /21 and advertise it to my larger provider.
You get that /21 from my larger provider.
I advertise a /24 subset of the /21 to you.
If you ignore my /24, then traffic for it goes
to the larger provider and I pay him for the traffic, not you.


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