# BGP Extended Access-List Filtering

**URL:** https://forum.networklessons.com/t/bgp-extended-access-list-filtering/1294
**Category:** Lessons Discussion
**Created:** [December 29, 2016, 8:15pm UTC](https://forum.networklessons.com/t/bgp-extended-access-list-filtering/1294 "2016-12-29T20:15:27Z")
**Posts on this page:** 1
**Showing post:** 3

<div class="post-metadata">

### Author: ![ReneMolenaar](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/renemolenaar/32/488_2.png) [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [October 5, 2015, 12:49pm UTC](https://forum.networklessons.com/t/bgp-extended-access-list-filtering/1294/3 "2015-10-05T12:49:55Z")

</div>

Hi John,

Good question, it can’t be done…let’s look at an example:

`00000000 /24
10000000 /25
11000000 /26
11100000 /27
11110000 /28
11111000 /29
11111100 /30
11111110 /31
11111111 /32`

Let’s say you want to match /26 up to /29, the problem is that they don’t have a lot of bits in common…only the first two bits are the same:

`11000000 /26
11100000 /27
11110000 /28
11111000 /29`

Now if you would use wildcard 00111111 (63 in decimal) then it matches /26, /27, /28, /29 but also /30, /31 and /32.

It can’t be done in one statement but of course you can use multiple statements…just create one for /26, /27, /28 and /29 and you are done.

Rene

---

_[View the full topic](https://forum.networklessons.com/t/bgp-extended-access-list-filtering/1294)._